Ghost Boat: captain’s manual

Issued with every registered vessel. Read it before the hull is breached, not after.

Reading this at the console: press ? (or F1) at any time. The trainer pauses while you read. ↑/↓ scroll a line; PgUp/PgDn, Shift+↑/Shift+↓, or b/space scroll a page; g/G jump to the start and end; ←/→ jump between sections, and ? or Esc closes the manual and puts the exercise back as it was.

You command a ship by its instruments. You will never see a map of where the enemy is. You will see bearings, signal strengths and estimates, and you will decide what they mean. This manual explains every instrument, every control and every rule the trainer uses. The spec sheets near the end come straight from the fleet’s own data, so they are always current.

[!IMPORTANT] The one rule. Everything you know about other ships comes from your sensors. Everything they know about you comes from theirs. That goes for the enemy too, at every difficulty. If they found you, you gave yourself away.

Your orders

The flotilla commander, on the dock, to a skipper with the ink still wet.

Okay, green skipper. Here is your boat. Seventy crew who know their jobs better than you know yours, four tubes, and a long way from home.

The job is tonnage. Every ton you sink is a ton the other side doesn’t have, and that is how this war gets settled. So stay quiet. Hear them before they hear you. A ghost picks its own fights, and if a fight looks bad, you were never there. When it looks good, sink them, get clear, and come back for more torpedoes. Dead skippers sink nothing.

Nobody out there is a villain. They have orders too, and somebody like me on their dock, telling them to find you. Who was right is for the politicians.

Nobody is coming for you, either. No backup, no rescue, no second boat. Once the hatch shuts it’s you, your crew and the dark.

Sink ‘em all, skipper. Then bring my boat back.

Contents

1. How the trainer works
2. The console
3. Controls
4. Setting up the console
5. Reading the instruments
6. Drills
7. Flying a Newtonian ship
8. Passive array
9. Range from bearings: TMA
10. Active array
11. Gravity wells
12. Nebulas
13. Torpedoes
14. Electronic warfare: jamming and ECCM
15. Power, heat and signatures
16. Life support
17. Damage
18. How the enemy thinks
19. Tactics
20. Goals and scoring
21. The war campaign
22. Scenarios
23. Ship registry and specifications
24. Glossary
25. Enclosures

1. How the trainer works

You command a ghost: a submarine in space. Nobody out here can see anyone. Every ship knows only what reaches its sensors: the energy other ships give off, and the echoes of its own pings. Everything you know about the enemy, it gave away. Everything it knows about you, you gave away.

The hunt

Every engagement is the same loop, on both sides. The side that gets round it first, quietly, usually wins.

%% The hunt, from first contact to getting home
flowchart LR
  L["Listen<br/>drift, quiet"] --> H["Hear<br/>a bearing"]
  H --> T["Track<br/>heard again and again"]
  T --> S["Solve<br/>leg change: range, course, speed"]
  S --> F["Fire<br/>a torpedo or a gun"]
  F --> C["Get clear<br/>break contact"]
  C --> L
  F -. "the launch is heard" .-> E["The enemy hunts<br/>down your bearing"]
  E -. "you are tracked" .-> X["Found"]
  style X fill:#ffdce0,stroke:#cf222e,color:#1a1a1a

1. Listen. Drift with the drive off. A drifting ship is quiet and its own array is at its best.
2. Hear. A contact appears as a bearing: a line on the rose and a streak on the waterfall. A bearing gives direction, never distance.
3. Track. Keep hearing it. Each new bearing goes into the contacts table.
4. Solve. Range comes from geometry. Change course (a leg change), and the bearings from your two legs cross. The solution grows from POOR to FAIR to GOOD. See Range from bearings.
5. Fire. A torpedo on a FAIR solution may miss; on a GOOD one it should hit. A spread covers the error.
6. Get clear. Inside about 600 km the enemy hears the launch: expect it to come down your bearing. Go quiet and slip away.

The enemy runs the same loop against you, with the same sensors and the same mathematics. It never knows where you really are; it knows only what you gave away.

What gives you away

The two numbers to remember: drifting, you are heard at a few hundred km; burning, at tens of thousands. Most of the job lives between them.

What new captains get wrong

[!IMPORTANT] “Speed is loud.” It isn’t. There is no water in space. A ship coasting at any speed makes only its reactor’s hum. The drive is loud, and only while it burns. Burn hard, then coast in silence.

[!IMPORTANT] “Turning changes where I’m going.” It doesn’t. Turning points the nose; only burning changes your course. Watch HDG and CSE part in the own-ship panel. See Flying a Newtonian ship.

[!IMPORTANT] “A ping only gives me away if it finds them.” It gives you away to everyone who hears it, which is everyone, far beyond its echo’s reach.

[!IMPORTANT] “Jamming hides me.” It hides what is behind your jammer from the ships inside its cone, and tells every ship in the sky exactly where you are. It is a defence against guided weapons, not a cloak.

[!IMPORTANT] “A contact on the rose is a target.” It is a direction. Until you have a solution you don’t know how far it is, which way it’s going or how fast.

[!IMPORTANT] “Once I’ve fired, it’s over.” Firing is the loudest thing a ghost does. Escorts hunt the firing point, and many goals ask you to get clear afterwards.

Two ways to fly

How you fly depends on your hull.

• A civilian hull flies on autopilot. A small generalist crew leans on automation. The arrow keys act at once: ←/→ steer, and ↑/↓ set the speed the autopilot holds along your nose (AUTOPILOT in the header). Press c to take manual control (MANUAL): then ↑/↓ step the throttle, still at once. Easy and forgiving, but a ship that holds a steady speed is easy to predict, and easy to hit, and the autopilot radiates EF the whole time it is on. To hide, switch it off.
• A warship flies by orders. The navy has no autopilot. The arrow keys dial a heading, a pitch or an engine order (ORDER in the header), and Enter gives it. A specialist crew carries it out: the helm in about 3 seconds and the engine room in about 4, slower when tired or short of air (ANSWERING while they work). Plan a moment ahead: a stop ordered late is a stop overshot. In return, the navy has the better weapons, sensors and manoeuvres.

The civilian tutorials teach the autopilot; the naval ones teach orders. See Controls.

2. The console

┌ header: ship · XPDR · zone · drive state · PING · ASSIST · clock · scenario ┐
│ bearing rose            │ passive waterfall (bearing across, time down)    │
├ status                  │ contacts: bearing, elevation, signal, TMA        │
├ log ─────────────────────────────────────────────────────────────────────── ┤
└ key bar ─────────────────────────────────────────────────────────────────── ┘

Instruments follow one rule: labels are dim, values carry the color, and color means something is wrong. A quiet, green board is a good board. Look for the one reading that has changed color.

You are the captain

You give orders; the crew carries them out and answers. Every order on the conn is acknowledged by the station that does it (HELM, SENSORS, WEAPONS, COUNTERMEASURES, ENGINEERING, COB, DAMAGE CONTROL), and the crew reports on its own: damage control on what it is fixing and how long it will take, the chief of the boat on the air, engineering when the plant acts by itself.

The windows that run a department, engineering and damage control, open on a captain’s summary: what you can do and for how long, in words with gauges for the battery, fuel and heat (“Battery 100%, about 35 min left at this draw”). Press i on the focused window for the detail: every gauge and number. Leave everything on AUTO and the crew runs it sensibly; reach into the detail when you want to run it yourself.

Windows

The console is a frame that never moves (the header, the goals and the key bar) around six windows: one large main window and five smaller ones. Any window can show any instrument, so you can set the console up the way you like to fight.

The bottom strip holds the log by default. Your windows and layout carry from one engagement to the next.

Two dynamic windows open over the main window by themselves, then close:

• TORPEDO, top right, while you can hear an enemy torpedo: its bearing, its signal, and CLOSING when it is getting louder.
• DAMAGE, bottom right, while the master alarm is unacknowledged and the damage report isn’t on screen: what is hurt.
• NOTICE, bottom left, for a few seconds after an alert, but only when the log is not on screen to show it.

Header

Goals

When a mission has goals, a GOALS line sits under the header: ○ still to do, ● done, ✕ failed, with (optional) on goals that don’t decide the result. A goal that means going somewhere shows its bearing and range, ⊕ 045° 1,200 km, and the same ⊕ appears on the rose’s ring and on the nav plot, with a circle showing how close you need to get. When the mission has advice for the current goal, it appears in a second line underneath.

Stay undetected means no hostile ship may track you: hear you several times within a minute. One lucky faint detection doesn’t count, but the hunter may come looking. Civilian ships hearing you don’t count.

What each kind of goal asks, and how a patrol is scored: Goals and scoring.

When the mission ends, a box says MISSION COMPLETE or MISSION FAILED, with the reason and the time taken. l reviews the log; q returns to the trainer.

Bearing rose

A compass card centred on you, with its own scale, shown in its title (±2,000 km): the wheel over it, or [ and ] when it’s focused, step the ring in or out, and the inner ring is half that, labelled. Anything you have a position for gets a • at its range, and its line stops there; a contact with only a bearing stays a line to the ring, and one off the scale keeps its range in its tag. Bodies and waypoints sit at their range too, and a dotted red ring shows how far off you can be heard (HEARD AT). Mark a bearing: click inside the focused rose to set your own mark, and hold the button to drag it round the card; the tag reads it as it moves (MARK 045). mark 045 on the conn does the same, and mark off clears it. It stays on that true bearing as you turn, and it’s yours alone: leave it on a contact, and if the contact stays on your mark while it gets louder, it is on a collision course. Click the title bar to swap the rose into the main window. It has two settings. o switches every bearing display together; to set the roses alone, type rose relative or rose true (which sets every rose on screen):

• True (the default): 000 is up. The fleet’s 000, its “north”, points toward the galactic centre, so N on the card is coreward. Bearings match the waterfall and the contacts table, which are always true.
• Relative: your bow is up, and the card turns as you turn. Ticks read relative bearings (0 dead ahead, 90 starboard beam, 180 astern), and the contact and waypoint tags read from the bow the way the contacts table does (S045, P135); a ✦ on the ring marks the galactic centre. Use it to see at a glance what is ahead, abeam or in your baffles. The helm dial, ordered heading and course tags show both figures in either mode, relative first here as P050 027°, and true first on the true card as 027° P050.

The galactic centre is a fixed direction, but where an engagement lies against it is not: each time you start one (the training lessons aside), its layout is turned a different way. Bearings in the briefing and the goals are the bearings for this patrol.

The waterfall has the same two settings (o with the others, or waterfall relative / waterfall true on their own); see Passive waterfall. The contacts table can show relative bearings too (o with the others, or contacts relative / contacts true). Each window keeps its own setting, so one waterfall can be true and another relative. Console setups save them.

• Solid line from the centre: your heading, where the nose points, with its number at the tip (045°).
• Your own torpedoes have their own lines, in the threat color, tagged with tube, time to impact and range (T1 02:32 ~180 km). They come from fire control, not your sensors: ~ marks dead reckoning from the launch, and a torpedo on a guidance link shows where it really is. Everything else on the rose is what your sensors hold.
• Dotted line, in its own color (lime in the default theme): your velocity, where you are actually going. Its length shows your speed, and its tag gives your course and speed (012° 0.60 km/s). Under the centre, z +0 km is your own height in the fleet’s frame. When it parts from the heading line, you are sliding.
• Short amber tick outside the ring: the heading you have ordered, with its number, while the helm is still turning.
• Lines toward the ring, labelled S1, S2…: contacts, drawn at their last bearing. They all stop at the ring, because the passive array gives no range. Each line carries a tag: the ID, bearing and elevation (S1 321° +04°). Once you know the range, from a FAIR or GOOD solution or a ping echo in the last minute, the tag adds it with its error, how far above (↑) or below (↓) you it is, and whether it is closing or opening and how fast in km/s: S1 321° +04° 550 km ±53 ↑38 km closing 0.40. Ranges are straight lines in 3-D. Without a solution, a held contact’s tag says louder or fainter when its signal has changed over the last half minute. A small rose shows only the ID and range. When many contacts lie in one direction, their tags spread out along their lines and step up or down a row, so none covers another; the most urgent (torpedoes, then anything closing, then GOOD solutions, then the nearest) keep their full tags, and the rest shorten to ID and range, or the bare ID. The contacts table always has every number. Held contacts pulse; lost ones are faint.
• Hatched wedge astern: your baffles, the arc your array cannot hear.
• Hatched sector with a short name: a charted body, such as a moon, covering that part of the sky.
• Shimmering band inside the ring: a nebula, across the bearings it covers, in its kind’s color. Inside one, the band runs all the way round.
• Bright ray that fades: a ping you just heard, pointing at the ship that sent it.
• Ring spreading from the centre: your own ping going out.
• HEARD AT ~ in the top corner: your own estimate of how far off you could be detected now, by channel (P 1,240 km · I 310 km · M 12 km). It takes what you are giving off against a typical hunter’s sensors (a destroyer’s if you are a warship, a pirate raider’s if you are a civilian), drifting quietly, as a boat’s own-emissions monitor would. It allows for the cloud you are in, as if the hunter shared your weather; a backdrop, or dust between you and a hunter in clear space, it cannot know. The real listener may be better or worse, so treat it as a guide. Burn, ping, transmit or run the autopilot and the numbers jump.
• Red-shaded sector: a contact whose known range is inside your heard-at range. It can probably hear you.

Bearing marks

A bearing mark is a ruler laid across the rose. It stays on its true bearing while everything else moves, so it is how you see a change that is too slow to notice by eye. You can lay three, A, B and C, and each shows both figures, first in the card’s own frame: MARK A 024° P053.

With the pointer, click a focused rose to lay a mark. Press within about 8° of one to take hold of it and sweep it round.

What it is for:

• A collision course. mark s1, then watch. If S1 stays on the line and its signal grows, it is coming straight at you. A bearing that holds steady is the oldest warning at sea, and it needs no solution.
• Which way a contact is drifting. If it walks off the mark, you see which way and how fast. Bearing rate is the first clue to range: a close contact walks quickly, a distant one hardly moves.
• Bracketing a convoy. Lay A and B on the two ends of the column. If the gap between them opens, you are closing, and if it narrows, you are falling behind.
• A danger sector. Lay marks either side of an escort and keep your bow out of the wedge, or either side of a tube’s arc to see what it can reach.
• Remembering a bearing. The last place you heard a contact, or the line your torpedo took. A hunter will come down that line, so mark it and leave it.
• Reading a figure. Sweep a mark onto anything on the card and read the bearing off its tag, then use it in an order.

Track symbols

Every display marks a contact the way a military plot does, after the MIL-STD-2525 and APP-6 standards. One shape and colour per affiliation, the same on the plot, the chart and the contacts table:

A contact the crew calls a fighter wears the top half of its frame, as air tracks do: ◠ friendly, ⋀ hostile, ⊓ neutral, ⌒ unknown. See Flight decks.

A mark’s label carries what is known: its range and error once a solution or an echo gives one, its course and speed from the solution (S1 780 km ±60 329°/0.10), and how long since it was lost. Zoomed out past 5,000 km, labels keep the range only. A lost contact stays on the plot at its dead-reckoned position, faded, with its uncertainty ellipse growing.

Nav plot

The nav plot can go in any window (see Windows); n steps a nav display from the rose to the plot, then its side view, then the 3-D view, then back. [ and ] zoom in and out; the title shows the scale (half the plot’s height).

The plotting overlay: think of a sheet of glass over the map, and a grease pencil. Click the focused plan to arm a course toward that point: a pulsing arm runs out from your boat with its bearing, as the helm dial’s does on the rose, and ORDER shows in the header. Click again to move it, Enter gives the order and Esc drops it. A clicked course lapses after 8 seconds, with the countdown in the ORDER pill, so a stray click can’t lie in wait for your next Enter; touch the arrows and it becomes a dialled order, which stays. Any movement of the mouse makes it a pan, not a click. If Enter gave a clicked course when you meant to open the conn, a letter in the next 2 seconds goes to the conn rather than to a hotkey. Only the bearing is used, and the order is a heading: as with any helm order, on a warship it turns the nose and your course changes when you burn. Press p to take up the pencil, and the plot’s title says PENCIL: then click to write a note, drag to draw a line (a track, a boundary, an intended course), and click a mark to rub it out. Press p again to put it down. With the pencil down, left-drag moves a note. The right button works as the pencil at any time, if your terminal passes it to the trainer; iTerm keeps it for its menu unless you change that in its settings. On the keyboard, note TEXT on the conn writes at the plot’s centre, overlay undo takes back the last mark, and overlay clear wipes the glass. Marks stay where you put them on the map, show on the plots and the chart, and the ship keeps them with the save, the bearing mark too. They are yours alone: they add nothing the boat doesn’t know, and nothing in the simulation reads them.

Move the plot: drag it with the mouse to look elsewhere. It stays where you put it, on the map, and its title says off centre. centre s1 on the conn follows a contact you have a position for, at the position your solution or fix gives, and holds its last place if you lose it; its title says on S1. centre alone comes back to your boat, and C goes home: the plots on your boat, and the plots and rose at the standard range, ±2,000 km. All the nav plots share one centre. Clicking a focused plot’s title bar swaps it into the main window.

• PLAN looks down from above: east right, north up. PROFILE looks from the side: ahead (along your heading) right, up up. Use PROFILE to see who is above or below you.
• 3-D is the same plot turned and tilted, so you can see the third dimension. < and > turn it 15° at a time; { and } tilt it 10° at a time, from edge-on (0°) to straight down (90°, the plan view again). The range rings lie flat at your level, with N marking north. Every contact you have a position for (a TMA estimate or a ping echo) stands on a dotted drop line to that level. A drop line going up means the contact is above you, and one going down means it is below; its length is the height difference. Lines of bearing are drawn in 3-D too, so after a turn of the view a bearing that climbs is easy to see. A contact you only have a bearing on has no position yet, so it has no drop line.
• You are the ◆ at the centre, with a solid heading line, a dotted vector showing where your velocity carries you, tagged with your course and speed, and a fading trail behind.
• Vectors run for a standard time, shown in the plot’s title (vectors 30 min): 1, 3, 6, 12, 30, 60 minutes and up, chosen by the zoom, as on a ship’s radar plot. Every vector on the plot runs for the same time, so a longer line is a faster ship.
• Charted bodies are drawn to scale, with their names.
• Nebulas are shimmering clouds, to scale, with a name and kind (the Veil · DUST).
• Lines of bearing run from where you were when you heard each bearing. If you fly straight they stay parallel and never meet. After a leg change they cross, and the crossing is the target. This is TMA, drawn.
• TMA estimates appear as an ellipse (2σ, so the target is very likely inside) with the contact’s ID, and a dotted vector showing where its estimated course takes it. Amber means FAIR; threat color means GOOD. The ellipse shrinks as the solution improves.
• Ping echoes appear as small amber circles.
• The red dotted ring is your heard-at range, the farthest of the HEARD AT estimates on the rose. Anything inside it can probably hear you.
• Labels step aside when they would cover one another; the most urgent (torpedoes, then held contacts, then the nearest) keep their full text.
• Your torpedoes are • in the threat color (orange in the default theme) with their tube and time to impact (T1 02:32), and a dotted line to the × where fire control expects them to meet the target. Your gauss gun slugs are grey dots. Enemy torpedoes are red contacts, with red lines of bearing.

• A thick amber band on a bearing is a range band: the near and far limits on a contact you hold on a bearing alone, tagged ?200-900. See The range band.
• ⊗ launch 12m is a loud mark, with its ring. See Loud marks.

The plot only shows what you know. Nothing is drawn where you haven’t heard anything.

What the plot draws

Each plot chooses its own layers, and a setup saves them. layer lob, layer ellipses, layer vectors, layer trail, layer rings, layer labels, layer bands, layer loud and layer craft (your own craft’s rings home, on a carrier) turn each off or back on; layer reach turns on the reach rings, which start off. layer reset puts them back. vectors 30 runs every vector for 30 minutes, and vectors auto lets the zoom choose. W, or w on a focused plot, opens the plotting menu: everything in this section, with a tick beside what is on, for pointing at.

Shadows

shadow s1 shades the part of the plot that S1 cannot see, behind charted bodies and, more softly, through thick dust. The title reads SHADOW S1 ±53 km. Use it to find the way out of a hunter’s sight, or to keep a moon between you and an escort.

A shadow is drawn from where your solution puts the contact, not from where it is. Its uncertainty blurs the edge: dense hatching is hidden from everywhere the contact may be, and thin hatching only from part of that. A poor solution gives a vague shadow, and a bad solution gives a shadow in the wrong place. It needs a FAIR solution or a recent echo; POOR gives none. As a solution ages its edge spreads, and if the estimate goes, the title says no estimate and the shading stops.

shadow own shows what you yourself cannot see. Up to three shadows show at once, each with its own hatching (one in a narrow window). shadow s1 again takes it off, and shadow off clears them. The shading lies on the plane through the plot’s centre.

The range band

A contact on a bearing alone has no range, but it does have a signal. If it is that faint, it can be no nearer than its quietest likely class would be, and no farther than its loudest. The plotter draws those two limits as a thick band on the bearing, and the contacts table reads ?200-900, in km. A far limit past 10,000 km says only that she may be far off, so it reads ?1.0k+. info s1 gives the same limits in full.

The ? matters. The band is a limit, never a firing solution. Fire control takes nothing from it, so it does not replace a leg change and TMA. It is wide because a ship may be drifting silent or burning hard, and the band has to allow for both. It rests on the classes the crew still allows, so it narrows as they make up their minds, and a wrong call gives a wrong band. It allows for jamming and masking in that beam, because your array measures those, but it knows of no dust on the path, which makes a near ship sound far. Use it to ask whether a contact can be a threat yet, and whether it deserves a leg change or a ping.

Reach rings

layer reach draws what your torpedoes can do: a ring at the longest run of what you carry (reach MK1 1,200 km, in still space) and the arming circle (arms 40 km). Inside the arming circle a hit is a dud.

A contact with a position and a class call gets a dashed ring for each weapon that class carries, tagged S2 torp ~1,200 km, crew's call. These are the crew’s estimate. The ring comes from the class they called, so a bad call gives a bad ring, and a contact they will not name gets none.

info s1 gives your reach on a solved contact, per torpedo: MK1 holds ~1,180 km / runs ~640 km. The first is the farthest you can catch it from if it holds its course. The second is the same if it turns and runs at once, by the class called; with no class call the crew can’t say. Shooting between the two means a warned target can outrun the shot.

Loud marks

The plotter marks each place you were loud: a launch, a ping, a gun burst, a beam shot, a burn (⊗ launch 12m). A salvo is one mark, and a long burn is renewed every ten minutes. Around each mark a dotted ring grows at your own speed, so it always reaches the boat. It shows where you might be, to anyone who might have heard you at that spot. The last twelve are kept, fading over an hour; a narrow window shows only the latest.

A mark says only what you did. It never says whether anyone heard. Someone might have, and a hunter races to a datum. Use the marks to choose which way to run after a shot, and to see how long a loud moment stays dangerous. layer loud hides them and loud clear wipes them.

Zones and tripwires

A zone is a line the crew watches for you. zone alpha 500 sets a box 1,000 km across at the plot’s centre. zone on its own takes up the pencil, and the next drag on the plan draws the box; the title says BOX ALPHA. A box is fixed to the map ([f]) and runs through every height. When a held contact’s estimate comes inside, the crew calls ZONE ALPHA: S2 inside, by the estimate. and time drops to x1, as for any alert. So set an ambush, compress time and wait.

guard port 270 330 sets a guard arc from 270 to 330 degrees clockwise off the bow. It turns with the boat ([r]), and needs only a bearing: the crew calls GUARD PORT: S2 on the arc.

A tripwire reads only the sensor picture. It will not call a ship you have not heard, or a box contact you hold on a bearing alone, and an estimate in the wrong place trips in the wrong place. A contact that leaves and comes back within five minutes is not called twice. Mines are not called.

zones lists them, zone off alpha takes one down, zones clear wipes them, and with the pencil up a click on a box’s edge rubs it out. Zones go with the save. overlay clear wipes them with your other marks.

Chart

The chart is the plotting table’s paper copy: north up, fixed to space, and it remembers. It is not on screen at first; put it in a window with v (it pairs well with the main window, z).

• Your whole track, and ◆ where you are now.
• The charted world: bodies, nebulas (outlined in their kind’s color) and waypoints ⊕ WPT. A waypoint is a place in your orders, with an exact bearing and range. Nothing is there to hear.
• A mark ✕ for every contact you have had a position for, from its latest FAIR or better solution or its latest ping echo, with a ring showing the 2σ uncertainty. The label gives its age in minutes (S1 12m), and marks fade as they age. A mark stays where you last knew the contact was, even after you lose it, until something newer moves it. That is how far old knowledge can be trusted.
• The frame grows to take in new marks but never scrolls or shrinks, so the marks stay put on screen while you move.
• Every label sits beside its mark, clear of the other labels, the symbols and your track. In a crowd a contact’s label shortens to its number (S4).

Passive waterfall

The output of your passive array, the newest second at the top, older seconds scrolling down. It has two settings (o with the other bearing displays, or waterfall true / waterfall relative on their own):

• True (the default): 000, toward the galactic centre, in the middle, with 270 left, 090 right and 180 at both edges, the same layout as relative with north in place of the bow. Turning doesn’t move a trace.

• Relative: the bow in the middle (000), port beam left (P90), starboard beam right (S90), and the baffles at both edges. A ✦ marks the galactic centre. This is what the hull array actually hears. Each row stays where it was when recorded, so when you turn, every trace shows a kink: old rows at the old heading, new rows at the new one. Real boats offer both; the true display is the array’s output corrected for your own heading.

• Background speckle is hiss. It is always there.
• A brighter vertical streak is a ship. Faint ones come and go; a steady trace is a contact you can follow. You may spot a trace before the tracker calls it a contact.
• A trace that slants is a bearing that is changing.
• A neutral grey band is your baffles, the arc astern where your own engine deafens the array. It is grey on every theme, so it never reads as a contact. It moves when you turn.
• Tinted hiss is a nebula’s bearing, in its kind’s color. Inside an ion cloud the speckle turns coarse: that is the static. A sharp white-hot crack that is gone in a second is a storm’s discharge.
• A white-hot mark is a ping. A whole row lighting up is your own ping: you are deaf for that second.
• Markers above the data (▼S1) show held contacts. Below the data, ▲ is your heading and △ your ordered heading.

Sensor waterfalls

Real heat. On engagements built on real physics (so far the Thermal Range), infrared is in real units. Your hull radiates whatever heat flows out of the heat sink, so an emptier sink means a colder, dimmer hull; engineering shows it as hull 191 K (-82 °C) radiating 91 kW. Radiators shed far more, but they are panels along your sides: from ahead, astern, above or below they are edge-on and hidden, so point your bow at the hunter. A burning drive’s plume is seen across a system. A telescope’s bearings are extraordinarily precise, thousandths of a degree.

Real EF. On the same engagements, the passive array is an EF array: it hears radio, in watts. A burning drive’s plasma is about 500 W on a warship, the reactor about a watt, a boat on its battery milliwatts, a datalink a kilowatt. Your own vessel is the loudest thing your array hears: light the drive and you go deaf, and the arc astern is deaf. Ion clouds add static; dust doesn’t block radio. In the contacts table the array’s letter is F, and engineering shows your EF in watts (EF 30 mW). Each sensor’s waterfall has its own colour: infrared warm, EM cyan, magnetic violet.

Why nobody looks. There is no lookout and no camera. Hulls are painted a non-reflective black, so a hull reflects almost no starlight, and what it does reflect is lost among every rock and grain of dust doing the same. A glint could be anything at any range, and light is the easiest thing to fake. So a ship is found by what it cannot help giving off: its heat, its EF and its magnetism. The telescopes see heat, not light.

Magnetism. Every engagement uses real magnetism. Warships carry magnetometers that feel a ship’s magnetic field (shown in magenta), and civilian hulls carry crude ones. A ship’s field comes from its reactor’s coils and its steel hull: with the reactor running, a destroyer feels an attack boat at about 14 km; with it shut down, the coils’ field all but goes, the hull’s own field stays, and the destroyer must come within about 6 to 7 km. A navigational shield adds its own coils, and every hard turn or pitch adds up to as much again. It is the point-blank channel, and silence does not hide you from it.

Searching the sky. A telescope sees far only where it is pointed. It points at what you already hold: the few contacts most recently heard on any channel (yours, or shared by the group), and any sector it has been set to watch. The rest of the sky is covered by a wide survey a tenth as far. So being heard, on any channel, brings the telescope onto you; and a ship nobody is looking for can pass where it would be seen easily. The survey window shows what your telescope is on.

Hiding in front of something bigger. A moon or planet between you and a hunter blocks everything. A planet behind you, as the hunter sees it, hides you too: its warm disk drowns the few watts of a hull. A magnetised planet’s field drowns magnetometers near it. Burning gives you away regardless.

Pings and mines, for real. On the same engagements a ping is a radar pulse. Its echo fades with the fourth power of range, so a destroyer’s radar finds an attack boat only out to about 10,000 to 20,000 km; the pulse itself is heard across the whole system. Echoes and pulses travel at light speed. Mines trip on real signatures: EF mines on a loud ship (an idling boat slips past). Magnetic mines trip on a hull’s field on every engagement (see Mines).

Transponders. Civilian ships carry a beacon. A trader broadcasts it, and it is a dead giveaway: a warship hears it from millions of km, and it gives your name, class, position, course and speed every 30 seconds. Yours starts off; transponder on or off on the conn. The header shows XPDR ON while it broadcasts. Going dark where a beacon was is suspicious in itself.

The rules of war. A transponder says two things: “I’m here”, and “I’m on this side”. In friendly space every merchant broadcasts, as the law of the lanes requires. In a war zone a merchant sailing under escort may lawfully run dark, and many do. An unescorted merchant is bound to broadcast, but many run dark anyway, against the rules, and a dark merchant alone in a war zone is a lawful target. A merchant’s beacon follows her situation: one that loses her escort may light up, and one that gains an escort may go dark. Your crew reports a change on any contact you hold (COMMS Beacon on S3., COMMS S3's beacon has gone dark.). An enemy merchant’s beacon names her side, so she reads as hostile (◇), and the crew remembers it after she goes dark. The debrief records whether each merchant you sank was broadcasting at the time. An enemy merchant is a lawful target whether she broadcasts or not. Sinking a friendly or neutral merchant who broadcasts honestly is a breach of the rules of war: the fleet reprimands you, your reputation suffers, and the breach costs you rank. A ship flying a false beacon has given up that protection, so sinking her is no breach. A pirate keeps no rules of war, so a captain sailing as one is never charged.

Collisions. Hitting a moon destroys you. Hitting another hull costs each ship by its mass: the lighter one takes the worse of it, in the ratio of their masses, so a ghost that touches a freighter comes off far the worse. Damage rises with the square of the closing speed. A ghost is wrecked by a closing speed around 100 m/s against a heavy hull, and at a km/s or more both ships are gone. The hits knock systems as a weapon’s do. A hull that survives a crash may still tear: a breach in a pressure hull can run along the frames until the ship snaps in two. Any real crash carries at least a one-in-four chance of that, rising to certain at about a 38% loss of hull, so ramming is a last resort. It also earns nothing: a hull lost in a crash counts as neither sunk nor tonnage, and computer captains burn clear of any hull their solutions show coming close. The helm looks ahead. It calls a charted body on your present course 30 minutes and 5 minutes out (HELM Collision course: Mere in about 28 min, at 1.0 km/s.), and a contact whose solution passes within 5 km of you. Each call drops time compression to x1. A call on a contact is only as good as your solution, and a ship you haven’t worked out gets no call. A burn in progress isn’t counted: the helm calls the course as it stands.

Weapon arcs. Every torpedo tube fires in a cone. An attack boat’s tubes are fixed, three in the bow and one in the stern, each 30° either side of its axis, and heading and pitch both count. A destroyer or cruiser has trainable mounts on each side, 120° either way, and a raider or hunter faces forward. The TUBES line marks each tube B, S, P or R. Fire control picks the ready tube that bears best. You may fire outside the arc, as a WWII gyro angle allowed: the torpedo turns at 1° a second before its motor lights, so each degree costs a second of time and of burn, and the launch is 6 dB louder. At long range that can put the target out of reach, so aim the boat when you have time. Close in, a snap shot off the arc often beats a two-minute turn. bear s1 turns the boat to bring the nearest tube on, which may be the lone stern tube, so use steer s1 when a salvo wants the bow. Computer captains keep to the same arcs: they swing up to two minutes, then fire off the arc anyway.

Warmth. The cabin must stay warm. While there is power the heaters hold it at 20 °C; without it the cabin cools, and below about 10 °C the crew starts to slip. A flat battery is not a quiet win.

Every window says what it shows. The title names the sensor and what it senses (PASSIVE ARRAY · EMISSIONS BY BEARING, INFRARED · HEAT BY BEARING), and a legend on the bottom border says how to read it: which way the bearings run, that the newest second is at the top and how much history the window holds, and that brighter means stronger. The rose, plot, chart and contacts table carry legends too. A small window shows a short form, so bigger windows (or a bigger terminal) show more: a waterfall holds two seconds per row, so a short window holds only seconds of history.

Layers (w on a focused waterfall, again for the next) lay more over the picture, as a ham radio’s panadapter sits over its waterfall:

1. Spectrum and guides. A strip on top shows the last few seconds as bars across bearing, with two reference lines: the floor (the background) and the threshold (the level at which the tracker can call a contact). A peak poking above the threshold is something you can hold. Guide lines run down the waterfall every 30°, your own heading is traced over time (a turn shows as a step), and time ticks run down the right edge.
2. The other sensors (warships): infrared, EM and magnetic returns tinted over the picture in their own colors, so one window shows which sensor sees what.
3. The tracker’s picks: a dot at every bearing the tracker measured, over the raw trace.

Estimated courses. With a FAIR or GOOD solution on a moving contact, a small arrow at the end of its line points along the estimated course: dim on FAIR, bright on GOOD, fading once the contact is lost. It shows direction only, and it is the boat’s estimate, so a wrong solution draws a wrong arrow.

On the rose, w hides or shows your own torpedoes in that window, for a crowded picture. filter held, filter weapons, filter solved (FAIR or better, or an echo) and filter hostile narrow what else that rose shows; give the order again to lift one, or filter off for them all. The title says only held. A filter hides a line and nothing more: the sensors keep working, the alarms still sound, and a contact called a torpedo stays on every rose. W opens the same choices as a menu. The title says when they are hidden, a setup remembers it, and enemy torpedoes always show.

Tuning: like tuning a receiver to one frequency and listening, put a cursor on one bearing and hear everything from that direction. Click inside a focused waterfall, nudge with , and . (2° a press), or type tune 045, tune s1 or tune off. Every waterfall draws the cursor, and the bottom border reads out each sensor’s level on that bearing and any contact within 4° of it, with its track symbol and its range once known: TUNED 034° · array +33 dB · IR — · EM — · ✣S1 at 034° 1082 km ±3. Bearings follow the window’s mode (S034 when relative). A narrow window trims the readout from the right.

What you get depends on the ship.

• A civilian ship has one display, SENSORS · FUSED: everything its sensors pick up, emissions and transmissions alike, in one waterfall. Its sensors are less sensitive, and it can’t tell you which sensor heard what.
• A warship has a separate, more sensitive waterfall for each sensor it carries, each in its own window:
  • PASSIVE: the passive array, as above.
  • INFRARED: heat. Sharp bearings (about 1°). A boat glows when its radiators are out or its drive burns.
  • EM INTERCEPT: transmissions: a group’s datalink, and the flash of guns and beams. Silent ships show nothing.
  • MAGNETIC: the magnetometer: hulls, powered or not, mines included. Broad, blurry bearings, and only at very short range.

  Each marks only the contacts its own sensor has heard in the last minute, so comparing them tells you how a contact gives itself away. The sensors station (F3) puts them side by side.

A station built for a warship, opened on a ship without those sensors, fills the spare windows with other instruments.

Comms

The comms station’s window: who can hear us, and who we are talking to.

• TRANSPONDER: off in hostile space; nothing announces you.
• DATALINK: your group, the link’s health, and whether you are TRANSMITTING this second. Sharing a contact with the group is an EM transmission, and EM intercept hears it.
• The group: each ship with its class, bearing and range, from the datalink.
• TRAFFIC: your orders, and every report about the group or the link, newest at the bottom.

Fire control

The weapons station’s window answers one question: can I shoot, and if not, what must change? setup weapons opens it, v reaches it in any window, and show fire puts it in the focused one.

The top line gives the exploder setting, the tubes and the magazine. Below that is a grid. Each row is a contact you hold, with the crew’s call and the solution’s quality. Each column is a weapon kind aboard. A cell reads OK, with the time to the meeting or the range, or it names what blocks the shot.

The chosen contact’s row opens below the grid: one line per weapon, saying what would clear the block, such as load 2 mk2h or Close 840 km. On a contact whose class the crew has called, a clear line also gives their count of good hits to sink it, as an estimate. , and . change the row while this window has the focus, and info s1 and check s1 choose it too. Enter puts the first clear shot on the conn line, and you still give the order. If nothing is clear, it offers the first order that would clear a block. Clicking a row in the focused window chooses it, and clicking a cell puts its order on the conn line: the shot, or the order that clears the block, such as load 2 mk2h or bear s1.

The grid uses the same checks as your orders, and only fire control’s own figures, so a cell can be wrong exactly when your solution is. A moon in the way. When you fire, fire control checks the run to the aim point against the chart. If it passes through a charted body, the launch line says so: The run crosses Mere: it will strike it. The grid does not show this, so read the log after a shot near a moon. A window too narrow for the grid shows the chosen contact alone, one line per weapon.

Survey

The science station’s window: how each thing gives itself away.

• Each contact, with what each sensor (passive array, infrared, EM, magnetic) last heard of it: the signal in dB and how long ago. Grey means more than a minute old; · means never.
• SURROUNDINGS: each cloud (inside it, or its bearing and the distance to its edge) and each body (bearing and distance to its surface). These are charted, so their true positions are fair to show.
• WE SHOW: your own signature on each channel: EF, infrared (amber when the radiators are out), your magnetic field (MAG 6.0 kA·m², with ×1.8 manoeuvring in amber while a turn adds to it), and whether you are transmitting.

Status (your vessel)

Naming your vessel. The title screen draws a name for your vessel from its class’s naming tradition: ghosts after night birds and spirits, haulers after small birds, freighters after virtues, warships after hawks and resolve. Press r for another, or n to type your own (Enter keeps it, Esc cancels). Choosing a different engagement draws a fresh name.

The window titled with your vessel’s own name (NIGHTJAR, MUDLARK).

A gauge can break. Damage, or a quirk of the hull, can break the instrument behind a gauge. A dead gauge says so: its label is struck through and the reading says × NO DATA. A stuck gauge keeps showing its last reading, and a wrong one drifts further from the truth. Neither gives any sign. Cross-check them against the crew and against the engineering window, which has its own meters. See Broken gauges.

Contacts

The fire-control computer keeps working after a contact goes quiet: range, and a lost contact’s bearing, come from its last solution carried forward to now. Their colour says how old that solution is: the track’s own colour within a minute, amber up to ten minutes, faint after that.

Your own torpedoes are listed below the contacts as T1, T2… (by tube), in your own color. Torpedoes are fire-and-forget: a guidance link is a transmitter, and a quiet boat will not run one. So these numbers are fire control’s dead reckoning from the launch (est in the HEAR column), not truth: a homing torpedo that turns on its own is not where they say. A linked torpedo (link, the cruiser’s Mk 3) reports its true position and takes course corrections, at the price of the launcher transmitting for the whole run, on a beam that points at the target. The columns: bearing, range in km, course, speed relative to you, BURN or COAST, SAFE or ARMD (armed), and in the last column the time to the meeting point fire control aimed it at.

Log

Timestamped reports in plain language: new contacts, transients, solutions, pings, and anything else the boat wants you to know. Time compression drops to x1 whenever something important happens.

Crew reports. The crew says what the gauges show, each station in its own voice, so you can run the boat from the console. Engineering calls the battery as it passes 50%, 30%, 15% and 5%, the heat sink at 50%, 70% and 90%, fuel at 50% and 25%, and a channel turning loud on the SIG bars. The helm calls propellant at 50%, 25% and 10%, Steady on 045° when a turn is done, the drive answering an order, and acceleration near or past the crew’s limit. Navigation calls your height as you sink into a well. Damage control calls the hull after a hit. The chief of the boat calls the cabin cooling. Weapons calls a tube loaded, the gauss and the beam ready, and a torpedo’s last minute and last ten seconds to run. Sonar calls a contact’s bearing once it has moved 10°, a torpedo’s bearing every 30 seconds while it runs, the pinger ready, and jamming. A reading is called once as it crosses a line, and again only once it has come well back, and no report repeats within 30 seconds. Choose how much you hear with reports: reports normal (the default) gives what needs a decision and what is urgent; reports quiet keeps only the urgent; reports all adds the routine. The choice is kept for the next exercise.

Every gauge also has an answer at the console. Type its name: battery, heat, fuel, prop, hull, air, cabin, crew, helm (heading, course, speed and drive), pos, alt, accel, tubes, guns, pinger, cm or sig. The station answers from its own instruments, not from the gauge.

The panel shows the newest entries, and the wheel scrolls it back. In a window at least 44 columns wide and 7 rows high, a row of toggles runs along its top: ORD orders, CON contacts, FC fire control, ENG engineering, DC damage, NAV navigation, COM comms and SYS the trainer’s own notes. Click one to hide or show that kind, or give the order filter eng. With filter s1, a wide log window gives S1 a column of its own beside all traffic. filter off takes the contact away.

Press l to review the whole log: it opens full screen and pauses the exercise.

The mouse works here too: click a toggle or a word along the foot, click a line to put the cursor on it, and click it again to open it. A line that names a contact counts as being about it, so Ping. Echoes: S1...; S2... shows under both.

Entries are colored by what they say: your orders, your own log lines (bold), contacts, pings, transients and system notes. Lines that night orders keep off the running log show here, faint.

After the fight. Press l in the replay for the same log over the whole encounter, and every filter works. It opens at the replay’s moment. p closes it and moves the replay to the moment of that line, so you can read what the boat knew and then see what was true. The filter stays for the next time you open it.

Night orders

Night orders say what wakes you. Press N, choose it from the menu, or give the order night. The page lists each kind of event with four levels:

The trainer starts on the Standing orders. If you never open this page, nothing changes. ↑ ↓ choose a row, ← → change it, and Enter steps round. A click on a level sets it. Keys 1 to 4 choose a preset, and the header shows it beside the time rate unless it is Standing:

Lower alarms save real time, and they delay your answer to a new contact. That is the trade.

Three kinds always reach you. A torpedo or detonation, a hit on your boat and the end of the engagement always drop to x1. You can raise them to pause, but you can’t lower them. Night orders change only what reaches you. Your crew’s work and your alarm bell stay the same.

Your own calls sit at the foot of the page. The crew calls you once when each comes due:

Standing orders

Standing orders say what the crew does before you can answer. Press S, choose it from the menu, or give the order standing. Every row starts on hold, and a boat on hold does nothing by itself. If you never open this page, nothing changes.

↑ ↓ choose a row, ← → change it, and Enter steps round. A click on a choice sets it. x puts every row back on hold. The order standing lure decoy sets a row, and standing off clears the sheet. The header shows STANDING 2 while two rows are off hold. A row reads not fitted if your boat lacks the gear.

The crew is a drill, not a tactician. It answers about 20 seconds after the call on an average crew, sooner at Red and later on a slow one. It answers one torpedo call or one ping in two minutes, so the second torpedo of a salvo is yours. It does not know how far off the torpedo is, or whether that ping found you. It can’t weigh any of that, and you can.

The captain’s own call

The TYPE column is the crew’s opinion, and the crew can be wrong. These orders record yours beside it. They change nothing the crew or fire control does.

Your view shows in a CAPT column when the contacts table is wide, and after the TYPE when it is not. The vessel window shows it too. An ignored contact’s alarms still sound. Setting something aside is a real risk, so a torpedo from it reaches you as any other does. A torpedo itself never dims.

Signing in

The trainer signs you in each time you power up the console. It opens a secure line, checks your clearance and greets you, with your hours on the trainer as an officer’s record. This takes under two seconds, and any key or click skips it. The sequence does not run for a replay. Over a metered link it is one still frame, held for a second.

Your first time. Type your last name, Enter, then your first name, Enter. The first name may be left blank. The record keeps both, as Hale, Anthony. The trainer and the crew address you by your last name alone: the first name appears only on the captains page and your signature. From then on the trainer greets you by the time on your own clock (good morning, good afternoon, good evening, and less formally in the small hours) and asks nothing. Esc on an empty name goes straight to the title screen, with nobody signed in, and the trainer asks again next time.

Form FP-1138. After the name, the Fleet Personnel Office offers its application. ↑/↓ move between fields, ←/→ change an answer, and Enter moves on. Any field may stay “Not stated”. Esc skips the rest of the form, and your name stands alone. Choose a career stream, then answer four questions. Page 2 is the declaration: Enter signs it with your name, and the form comes back stamped ACCEPTED, with a score slip.

The score slip. The Navy Aptitude Assessment Test (NAAT) gives a line score out of 99 for sensors, navigation, engineering and tactics, a percentile, and a recommended career path. The recommendation is advice: the career you stated stands, and c on the captains page changes it. Your answers lean the scores and chance moves them. The office then reports what you tested as, from those scores and more chance, so the result may surprise you. It is rolled once and stays on your record. A form you skipped can be filed later with f on the captains page. The form also leans the four attributes of a captain’s sheet: nerve, cunning, aggression and seamanship. All of this is a service record. None of it changes how a boat handles or how an exercise is scored.

Captains. Several captains can share one trainer. Each has a name, a career, a level of difficulty, hours, records and saved exercises of their own. With one captain on the roster, the trainer signs that captain in. With several, you choose. C on the title screen opens the captains page at any time:

The list and these keys can be clicked as well. To skip sign-in for one run, start the trainer with --no-signin: it keeps the last captain and asks nothing.

Rank. Every captain starts at the foot of their career’s ladder and is promoted for missions completed. Lessons don’t count. Each breach of the rules of war takes three missions off the count, so a captain can be reduced in rank, and the service record shows a reputation, from clean through noted and questioned to notorious. The navy runs from Ensign to Commodore, the merchant service from Third Mate to Commodore Master, and a privateer from Prize Crew to Commodore of the Free Company. Rank is a record of experience and conduct: it changes nothing in an exercise. The trainer shows it beside your name and announces a promotion when you next reach the console. The enemy wears the same ranks, and theirs say roughly how experienced they are.

Awards. The fleet also notices outstanding work, once for each award, and lists them on your service record. Like rank, an award changes nothing in an exercise. Some are plain about what earns them and some are not; you will find out.

Careers. Captains are listed by career: Military, Civilian or Pirate. A career is a label on your record for now, and every career sails the war campaign. Your progress through it is your own.

Time on the trainer. Hours count the time spent in exercises, by the clock on the wall, including time paused. Replays and the title screen do not count. Your first captain inherits everything the trainer held before it had captains: past records and saved exercises. Replays are shared by all captains. Your roster is kept in roster.ron, beside your records.

Title screen

The Fleet Tactical Trainer opens on its main menu when you power up the console, after the sign-in. ↑/↓ (or k/j) choose an item, Enter opens it, Esc comes back from any page to the menu, ? opens this manual and q quits. The menu holds, in order:

• New Game: a career in a generated galaxy. It is not built yet, so it is shown faint and does nothing.
• Continue: your newest saved exercise, paused where you left off. It is listed only when there is a save. Its details show beside it; x opens the saves and replays page at its delete question (below).
• Training: the lessons, under CIVILIAN, NAVAL and GHOST, in teaching order. See Tutorials.
• Scenarios: the challenges, under the kind of boat you sail: CIVILIAN, NAVAL or PRIVATEER.
• War Campaign: the war in order: nine engagements in three eras, each opened by winning the one before. See The war campaign.
• Saved Exercises: every save and kept replay (below).
• Options: the theme, colors (24-bit or 256), effects, sound, CRT scanlines, Nerd Font icons, how much the crew reports, and the captain and sign-in. ↑/↓ choose a row and Enter changes it. The keys t theme, c colors, e effects, m sound, s scanlines and f icons work on every page, and C opens the captains page. Settings carry into the exercise and back.
• Manual and Quit.

Started with --dev, the menu also has a Dev item, just above Quit, that lists the test bench (see Scenarios).

Training, Scenarios and War Campaign each list their exercises with the chosen one’s briefing and best result. ↑/↓ choose one, and Enter begins it (or, for an exercise that offers a choice of ships, opens its setup page). A locked campaign step says which win opens it. Under the list are the choices for the next launch: d difficulty, l the load to sail with, i iron mode, b the boat and w the war.

Saves and replays. Saved Exercises, or a on any page of the title screen, opens a page listing every saved exercise and kept replay together, newest first: its name, scenario, date (UTC), level, outcome and, for a replay, the verdict band. (m is the sound setting, so the page is on a.) ↑/↓ choose, Enter continues a save or watches a replay, and Esc goes back.

• r renames a save you named, or a replay. A replay keeps its date and outcome in its file name, so it still lists and plays; an autosave or the iron save can’t be renamed.
• k keeps a replay, so it is never pruned (the trainer keeps the newest 50 otherwise, and a kept one isn’t counted among them); k again lets it go.
• d deletes, and always asks first: only y does it. It removes only the trainer’s own save and replay files. An iron-mode save can’t be deleted while its engagement is still running: continue it and finish the fight. One that won’t read can’t be finished, so it can be deleted.
• / filters the list by scenario (Enter keeps the filter, Esc clears it).

• A save or replay file that won’t read (a corrupt file, half of a save, or a save from an older version) is listed as unreadable, and can still be deleted. Continuing one from the title says “Can’t read that save.”

• Without iron mode an exercise keeps several saves: an autosave for each engagement, written every 5 minutes and when you leave, and any number you name yourself with save or save before the attack on the conn.
• In iron mode there is one save, written only when you leave. There is no autosave and no save order, and continuing from the save uses it up. An exercise keeps the iron mode it was started in.

Choosing ships. Some engagements, such as Duel, let you pick your ship, the opponent’s ship and its captain. On the setup page, ↑/↓ move between the choices, ←/→ change one, Enter begins and Esc goes back. Under each ship is a one-line summary: acceleration, EF drifting and burning, how quiet its array is (“ears”, lower is better), whether it pings, and its tubes.

Themes live in data/themes.ron: thirteen come with the trainer (Deep Signal, Phosphor Plus, Neon Tactical, Solar Punk Solarized, Amber Terminal, Red Light, the red lighting of a control room at night, Polaris, the cool Nord palette on a darker ground, Graveyard Watch, the Dracula palette on a darker ground, Field Service, in the blue of an old PC, Boldly Go, orange and lilac panels on black, and Letter of Marque, a sea chart in tar and gold, which comes up by itself when a privateer signs in, and Cold Steel, gunmetal and frost for a flight deck, and Imperial Bridge, grey deck plate with red and green panel lights). Copy one, change its colors and restart to make your own. If the file has a mistake, the trainer says so and uses its built-in themes.

Scanlines (s) darken every other row a little, like an old CRT.

Difficulty (d) steps the level of your next launch through Standard, Hard and Nightmare, for free play and the campaign alike. It belongs to the signed-in captain, so it is kept between sessions and each captain has their own. With nobody signed in, it starts at Standard. The first time you choose Nightmare it shows a warning: y sails anyway, and any other key backs out. Once you’ve accepted, it doesn’t ask again on this machine; the yellow label under the list says what you’ve chosen. See Difficulty.

Iron mode (i on a list of exercises) takes the pause away, as a real watch would:

• off: pause whenever you like;
• limited: three pauses per engagement, each lasting at most 30 seconds, then the trainer resumes by itself. The header shows IRON 2 for the pauses left;
• iron: no pausing at all (IRON in the header). The manual and the log viewer open over an exercise that keeps running.

Records. Each finished engagement is saved: won or lost, the time, the mode, ships sunk, hull left, the level, the verdict band and the tons sunk. A Nightmare run is marked as one. The title screen shows each engagement’s best (a win in a stricter mode beats a faster one in a gentler mode, and at the same mode a harder level beats a faster easier one), and at its head your heaviest bag and your running total of tons. Records live in ~/.local/share/ghostboat/records.tsv (or under $XDG_DATA_HOME).

If the colors look garish or wrong, press c for 256-color mode. Terminals reached over SSH often can’t say whether they support 24-bit color, so the trainer may start in 256-color mode; press c to try 24-bit.

3. Controls

The key bar at the foot of the screen lists the keys used most in play. The rest (t, e, m, r, zoom) are in the table above.

Mouse, touch and menus

Every action has a key, and every action can also be reached by pointing, so the trainer works without function keys, and on a tablet or phone over SSH.

• ☰ menu (first on the key bar): every command, with its key beside it.
• s stations: every console setup, built in or saved. The function keys are shortcuts to the same list.
• The key bar is buttons. Click an entry to press its key. On a pair such as ←→, click the arrow you want.
• Windows: click a window to focus it; click the focused window’s title bar to swap it into the main window, and again to put it back. Inside a focused waterfall, a click tunes to that bearing.
• The rose: click inside it when focused to lay a bearing mark. Press near a mark to take hold of it, and sweep it round. See Bearing marks. Press on the bow’s arm or the helm’s order and sweep it to dial a heading, then Enter gives the order and Esc drops it.
• The plotting menu: the ☰ menu’s plotting entry, or W, lists every filter, layer, shadow and zone order for the window, to click.
• The overlay: press p for the pencil, then click a plot to write a note or rub out a mark, and drag to draw a line. With the pencil down, drag a note to move it. See Nav plot.
• Plots: drag a plan, profile or 3-D plot to pan it. It stays where you put it, and C brings it home at the standard range. See Nav plot.
• The wheel works on what the pointer is over: it zooms a nav plot or the bearing rose, moves a menu’s selection, and scrolls the manual and log, the log window included. Scrolled back, the log window’s title says how far (12 lines back).
• Menus take ↑/↓ and Enter, the number shown, or a click; Esc or a click outside closes them.
• The title screen: click a menu item, an option or an exercise to select it, and again to choose it. The launch choices and the key bar are buttons too.

Running remotely. Locally, or over mosh, run as normal: mosh sends only the newest screen and never falls behind. Over plain SSH, start with --metered. Plain SSH sends every frame, so a busy screen such as the waterfalls queues up behind the link and the console seems to crawl. Metered, the trainer keeps its output to 32 KB/s (or --metered 16, or GHOSTBOAT_METERED=16) by skipping frames, and starts with effects off. The simulation keeps real time either way; only the screen updates less often. Sensor waterfalls redraw at most twice a second in every mode, and at once after a key or click.

With the mouse on, most terminals need a modifier to select text (in iTerm, hold ⌥ Option). Start with --no-mouse to keep the terminal’s own selection.

The conn

Press Enter (or :) and the bottom line becomes CONN>. Type an order and press Enter; the boat answers in the log. Esc cancels, and ↑/↓ bring back earlier orders. The exercise keeps running while you type, but time compression drops to x1. Every important action also has a single key, so you never have to type a sentence while something is closing on you.

Orders are not case-sensitive. Contacts are named s1, s2, and so on.

Nerd Font icons. Ghost Boat needs no special font. If your terminal uses a Nerd Font, press f on the title screen for icons in the window titles, the goals, the bars (HULL, BATT, SINK, FUEL, PROP), the torpedo stopwatch, and on waypoints ( WPT), mines, notes and the plots’ countermeasures. The SIG bars become joined capsule gauges, and a small spinner turns on the TUBES line while a tube reloads and beside a system under repair, if effects are on. These need Nerd Fonts 3.0 or later. A symbol means the same either way, and contact symbols (○ ◇ □ ✣, and a fighter’s ◠ ⋀ ⊓ ⌒) always stay as they are: they follow the military standard. If icons show as boxes, your terminal isn’t using a Nerd Font: press f again, or choose one, preferably a Nerd Font Mono, in your terminal’s settings. iTerm can keep your usual font and use a Nerd Font just for symbols, under Profiles > Text > Non-ASCII Font. The replay viewer stays plain.

Sound. The trainer uses your terminal’s bell, once, when you are pinged or hear a torpedo. Every sound has an on-screen twin (the PING and TORPEDO pills, the rose flash, the log line), so you lose nothing with sound off. In iTerm you can choose the bell’s sound under Settings → Profiles → Terminal; a sonar ping works well.

4. Setting up the console

The console is yours to arrange, and different jobs want different arrangements. Set it up once for each job and switch with one key.

Windows, layouts and detail

There are six windows: a large main window and five smaller ones. Any window can show any instrument: waterfall, rose, nav plan, nav profile, 3-D, chart, engineering, damage control, contacts, status, log, comms or survey, and on a warship the infrared, EM and magnetic waterfalls.

The console is built for a big terminal (160×45 and up): every window gets more room, and the waterfalls more history. It works down to 80×24; a lean layout for small screens is planned.

Setups

A setup is a whole arrangement under a name: the layout, what every window shows, and each window’s view (summary or detail; true or relative bearings). Think of a working ship: each station has its own view of the same boat. Nine setups come built in, on the function keys: seven stations and two situations.

The trainer starts on a console like bridge but with true bearings: the rose large, the sensors beside it.

Make your own. Arrange the console the way you like it and type setup save NAME on the conn (for example setup save attack). setup attack brings it back; setups lists every setup with its key. Your own setups are recalled by name (setup attack); the function keys are all taken by the built-ins. Saving under a built-in’s name (setup save combat) replaces that built-in with yours. Setups are kept between sessions in ~/.config/ghostboat/setups.tsv (or under $XDG_CONFIG_HOME).

Some arrangements worth trying:

• TMA work: the nav plot in the main window, with contacts beside it: watch the lines of bearing cross as the TMA grade firms up.
• Torpedo attack: contacts in the main window (your torpedoes count down there) with the plot beside it.
• Escort or hunting group: the chart in the main window, to see your group’s ▲ marks and every contact’s last known position at once.
• Minefield: the chart for the charted field, the waterfall for captor torpedoes, engineering in the summary for the battery.

Look and feel

These are under Options on the main menu, and their keys work on every page of the title screen. In an exercise, t steps through the themes, and theme NAME on the conn picks one (theme red for Red Light; theme alone takes the next):

Your own theme. Themes are in data/themes.ron. Copy a block, give it a new name, change the colors (#rrggbb), and restart. Every role needs a color; keep the roles’ meanings (threats stand out, faint things recede, warnings are unmistakable), because color means the same thing in every theme. If the file has a mistake, the trainer says which theme and which color, and uses its built-in themes.

5. Reading the instruments

Section 1 says what each instrument shows. This section says how to read it: the patterns an operator learns to spot, and what they mean for you.

The waterfall: reading traces

The waterfall is signal strength by bearing (across) against time (down, newest at the top). On the true display, turning your own boat doesn’t move a trace; moving it does, slowly. On the relative display, a turn kinks every trace by the amount you turned, so a kink that every trace shares is you, and a bend in only one trace is the contact.

The bearing rose

Each line points along a contact’s latest bearing. All lines stop at the ring, because passive array gives no range: a long line is not a near ship. A line that pulses is held now; a faint one is lost. A line that stays put while you move is either far away or coming straight for you; one that swings is crossing or close. Your heading is the solid line from the centre, your actual course the dotted one, and when they part you are sliding. A shimmering band inside the ring is a nebula; a hatched sector, a moon.

Identifying a contact

Nothing comes with a name. A contact is unknown until your crew has heard enough of it, and the TYPE column gives their best guess so far: first civilian? or military?, then a class. The array reads the character of its machinery and, when it burns, its drive and how hard it pushes; a ping reads the size of its echo. A faint contact takes far longer than a loud one, a quiet ghost may never be called, and similar classes stay confused. Ships in your own group are known. Infrared, EF and magnetic readings don’t count yet.

Crews can be wrong. Each new call has a chance of naming the runner-up, higher with a green or tired crew, and it stands until the evidence is overwhelming. The call in the table is the crew’s opinion, not a fact.

A transponder is a claim. It gives a name, a class and a position at once, but only what the ship says of itself. A position report gives you a range and a solution without a sound, and the tracker treats it like an echo. If the signature doesn’t fit the class, or three reports running don’t fit the bearings your own array measures, the crew marks it suspect and it stops reading friendly. A false position also leaves the track, which goes on from your bearings alone. A lie along your line of sight doesn’t show on the bearing until one of you moves, so a solution from a beacon is only as good as the beacon. Some lessons use older beacons that give no position.

The vessel window (info s1, or info for the latest heard) shows the call, the classes it could be with their odds, the beacon’s claim and reported position (and when it was last heard, once it falls silent), how long you have listened, and, once a class is called, what that class carries.

Torpedoes are identified too. The contact is only a TORP, and the alarm only sounds, once it is called, and the enemy plays by the same rule. A burning torpedo is called as soon as it is heard, because nothing else pushes that hard, but its motor is small: you hear it only inside about 600 km. Once it coasts it is a faint hum: the array alone won’t hear it until about 20 km out, some five seconds away. To find one in time you must ping, which tells everyone where you are.

Reading a contact

The contacts table holds one row per contact. Read it left to right:

• HEAR: which sensors have it. P (passive array) is the usual, and it means you found the ship, not that it announced itself. X means it is broadcasting a transponder beacon, and clears a minute after it goes dark. A small x then marks a held contact whose beacon has gone silent in the last ten minutes: switched off, or out of hearing. I (infrared) on a quiet boat usually means its radiators are out or it is burning. E (EM) means it is transmitting: a hunting group sharing a contact, or a gun or beam firing. M (magnetic) means it is close: a magnetometer feels a running warship at about 15 to 20 km and a cold one at about 6 to 7 km.
• SIG: how far above your threshold the signal is, in dB. Near 0: faint, it will flicker. Rising SIG: it is closing, or getting louder (burning). Falling: opening, or going quiet. A sudden jump of 6 dB or more is a transient.

• TMA: how far to trust the range, course and speed:

  Grade	Range is good to	Use it for
  ---- or POOR	nothing shown: don’t trust it	keep listening; make a leg change
  FAIR	within about 30%	a spread of torpedoes; steering toward or away
  GOOD	within about 10%	a single torpedo, a gauss gun burst, the beam
  FIX	a ping echo in the last minute: range to within a few km (about 10 from a civilian active array)	guns; a quick solution

  A solution assumes the target flies straight. One that is turning or still burning can fool it, so fire control checks several things. If the fit misses the bearings by more than their usual scatter, it widens its doubt. If a new solution would mean the target changed speed faster than any ship can burn, it is graded POOR. A target that has made a transient is held at FAIR or below for five minutes, in case she is still burning, unless an echo gives her range. After a convoy scatters, expect solutions to drop back to POOR until the ships settle on their new courses.

• RANGE km: the estimate and its uncertainty, one standard deviation (720±212: likely between about 510 and 930, and almost certainly between 300 and 1,150). The plot’s ellipse is drawn at two.
• STAT: HELD (heard in the last minute), LOST, TORP (a torpedo, in red), MINE. SUNK? is the crew’s call after breaking-up noises on that bearing (see Torpedoes for what they are in space). They go by the bearing and can be wrong, and a contact heard again goes back to HELD. drop s1 takes a silent contact off the table and the plots until it is heard again. A right click on a contact’s row in the table offers these orders and more.
• AGE: how long since last heard. An old HELD contact is a guess about the past.
• DZ km: how far above (+) or below (-) you it is, once you know its range.

Your own torpedoes are listed below as T1, T2…: dead-reckoned estimates (est) unless linked (link), with the time to impact counting down in the last column.

The nav plot and the chart

On the nav plot, lines of bearing run from where you were when you heard each bearing. Parallel lines mean no range: you have been flying straight. Lines that cross mean a leg change worked, and the target is where they cross. The ellipse is where the target probably is (2σ); a long thin ellipse lying along the bearing means range is the doubt, not bearing. The dotted line from it is where its estimated course takes it in ten minutes. If that line points at you, it is closing; if it runs across your bow, it is crossing, and a torpedo needs to lead it.

On the chart, a ✕ is where a contact was, not where it is: read the age (S1 12m). A coasting ship has moved by its speed times that age. Marks fade over an hour; trust a fresh one, treat an old one as a place to start looking. ✱ marks mines, which don’t move.

The captain’s summaries

Engineering in words:

Damage control in words: the hull, what the parties are on and how long (“working again in about 4 min”), and what you can and can’t do by job: MOVE, POWER, HEAR, FIGHT, TALK. A job that says OK is fine; anything else names the system and how bad.

The pills, and what to do

6. Drills

Standard ways to do the common jobs. The keys are in brackets; any of it can also be ordered on the conn.

Get a solution (TMA).

1. Drift and listen until the contact is HELD with a steady SIG.
2. Turn about 90° to its bearing (beam s1), burn briefly (↑ and Enter, a few seconds to half a minute), then cut (x). The engine room takes a few seconds to answer, so cut a little early.
3. Drift and wait. Within a few minutes TMA goes FAIR, then GOOD. On the plot the lines of bearing start to cross.
4. Faster but loud: ping (P) for a FIX.

Attack with torpedoes.

1. Get a solution: GOOD for one torpedo, FAIR for a spread. A big hull wants several hits, whatever the solution.
2. Close to well inside a few hundred km, but stay beyond 40 km: inside that the warhead won’t arm.
3. Fire (f, or salvo 2 s1). Watch T1 count down in the contacts table and on the plot.
4. A detonation with breaking-up noises is a kill. A detonation on a hull with no breaking-up noises means she is hurt and still there, so fire again or leave her. “Run ended, no hit” means a miss: refine the solution and fire again.

Evade a torpedo.

1. TORPEDO IN THE BLACK: note its bearing.
2. Drop a static buoy (j) and slide off its line: turn so the torpedo is on your beam or astern and burn briefly.
3. Cut the drive and go quiet (b). A homing torpedo chases the loudest thing it hears; make that the static buoy.
4. A decoy (d) running on along your old course draws hunters off while you turn away.

Slip past a hunter.

1. Find it by ear while it is far off. Note its bearing drift.
2. Make any course change early and gently, while it can’t hear you (thr 1 or less).
3. As it passes, rig for silent running (b), or ultra-quiet (ultra) if the battery and air allow.
4. A PING or a transient means it suspects you. Stay quiet unless it is clearly coming for you.

Clear your baffles. Every few minutes, turn 60 to 90° (right 60), listen for a minute, and turn back. Anything that was hiding astern shows up.

Run a minefield. Rig for silent running before you enter (b): quiet beats acoustic and captor mines, and a cold reactor shrinks magnetic ones. Don’t burn inside. Drop a static buoy on any torpedo. Pinging finds mines, but tells everyone where you are.

Take damage. a to acknowledge, then read the damage summary. Damage control is already on the worst of it. Change its priority only for a reason (“I need the tubes before the drive”: repair tubes). Avoid relying on a system marked FAILED.

7. Flying a Newtonian ship

Your ship obeys Newton, not the sea.

Your crew answers your orders. You are the captain: you give orders, and the crew carry them out after a moment. An average crew answers the helm in about 3 seconds and the engine room answers the telegraph in about 4. A tired crew, or one short of air, is slower. The header shows ANSWERING HELM 2s ENGINES 3s while they work, and the rose shows the ordered heading at once. A small correction to a standing order (under 5°, or 5% of throttle) is taken at once, as a helmsman follows a corrected course. Enemy crews work the same way: a green crew is slower than yours, a seasoned one a little quicker. x (all stop) goes through the engine room too, so cut early.

Controlled burns. The telegraph sets the drive’s output, not a speed: “ahead full” burns until you order otherwise, and in space you keep speeding up. For a precise change, give a manoeuvre and the helm and engine room fly it together, easing off as they near the mark, then cut and coast:

• burn to 2.5: burn along the nose until you make 2.5 km/s that way.
• burn 30: burn at full for 30 seconds.
• full stop (or slow to 0.5): turn end for end, against your velocity, and burn until you stop (or slow to 0.5 km/s). Space has no brakes; this is how you slow down.
• burn off: stop the burn and cut the drive. Any engine order, x included, also takes over from a burn.

The header shows the burn as it runs (BURN TO 2.50 · 1.83 km/s), and the log says when it is done. Civilian hulls also have flight assist (c), which holds a speed for you; warships don’t, because a ship that holds one steady speed is easy to predict and easy to hit.

• You keep your velocity until you burn. Turning the nose does not change where you are going. Only thrust does. That is why the console shows heading and course separately.
• The main drive pushes along the nose. To change course, point the nose where you want the change to go and burn. To stop, turn around and burn against your motion.
• Everything is slow. Turns build up and ease off; the drive takes time to spool. Plan ahead.
• Speed is silent; the drive is loud. There is no water in space. A ship coasting at any speed makes only its reactor hum. Burning can be twenty decibels louder. Drifting is free and quiet.
• Propellant is limited. Every burn spends it. The registry lists each class’s total.

Flight assist. If your ship has a compensator, c engages flight assist: it fires thrusters to keep your velocity along the nose at a set speed, so the ship flies the way you point it. It is real thrust. It costs propellant, it can be heard, and near a moon it has to fight gravity the whole time. Use it to get somewhere; switch it off to hide.

8. Passive array

Your passive array listens. It gives you a bearing and a signal strength, and nothing else. It never tells you how far away something is.

What decides whether you hear a ship:

signal excess = target's emissions − loss over distance − your background − threshold

• The target’s emissions: louder ships are heard farther. Burning ships are much louder.
• Loss over distance: about 6 dB every time the range doubles.
• Your background: your array’s own floor, plus your own vessel’s emissions leaking in. Burning makes you deaf as well as loud.
• Threshold: how good your array is.

Near zero excess a contact fades in and out. Well above zero it is held steadily, with a sharper bearing.

Baffles. Every array is deaf in a cone astern, where its own drive is. A ship behind you can be close and silent. To check, turn: this is called clearing your baffles.

Transients. When a ship you can hear suddenly gets louder, the log calls a transient. Usually it is a drive lighting up, and often that means you have been heard and something is coming.

Moons block everything. No sensor works through a planet or moon.

9. Range from bearings: TMA

Target motion analysis turns a series of bearings into a range, course and speed. Each bearing says “it was somewhere on this line, at this moment”. If the target holds a steady velocity, only one track fits all the lines. In space a coasting ship really does hold a steady velocity, so TMA here is very good, if you give it what it needs.

[!IMPORTANT] You must maneuver. If you fly a straight line, range cannot be worked out, however long you listen. Change course (a leg change), burn briefly, drift again, and the solution firms up. Watch it happen on the nav plot: the lines of bearing start to cross.

Quality is the uncertainty compared with the range: GOOD under 10%, FAIR under 30%, otherwise POOR. POOR solutions show no numbers, because they mean nothing yet. If the target maneuvers (a transient), its solution starts over, and it cannot be GOOD again until she has run steady for five minutes (a ping echo skips the wait). Before it calls a solution GOOD, fire control also works the bearings again from a nearer and a farther start. If another track at a different range fits them about as well, the range is not known, and the grade drops to match.

A solution is an estimate, never the truth. Fire control works from bearings, and every bearing carries a little error, so even a GOOD solution can be off, and now and then badly off. That is how tracking by ear works, and the trainer keeps it so on purpose: the debrief’s true picture shows how far off you were. Another leg sharpens a solution. A straight runner trusts it completely, so it pays to wait for GOOD; a homing torpedo corrects its own aim on the way.

Better sensors make better solutions. Sharp bearings from a strong signal give a fast, tight solution. A civilian array on a faint warship may never get one.

Doppler

The passive array also reads the Doppler shift on a target’s narrowband lines: how fast it is opening or closing along the line of sight, relative to you. It is as sharp as the bearing in proportion, about 10 m/s for an attack boat’s array at the threshold, and sharper on a strong signal. What it does for you:

• It speeds up TMA. Bearings alone can’t give range from one straight leg; bearings with Doppler can (a test leg: 2,037 ± 34 km against a true 2,042). The solver allows for a target that may have changed course or speed: every bearing and Doppler reading counts for less the older it is, by how far a target could have strayed since, so fresh data leads and a manoeuvre doesn’t drag the solution off.
• It catches manoeuvres, even silent ones. Once a contact has a FAIR or better solution, every Doppler reading is checked against what the solution predicts. When they drift apart by more than 50 m/s, the log calls it (S1 manoeuvring, bearing 040°: its Doppler is off the solution. Starting over.) and TMA starts over from there, as it does after a transient. A target that turns on its thrusters without lighting its drive can no longer hide the turn.

10. Active array

A ping finds things. It sends out a pulse and listens for the echo, which gives range and bearing at once. Two echoes a few seconds apart give a GOOD solution almost immediately.

The catch. The echo has to travel out and back; the ping only has to travel out. So a ping is heard far beyond the range at which it finds anything. The registry’s active array table shows the gap: a destroyer’s ping finds a hauler at about 2,400 km, and that hauler hears the ping from more than 45,000 km.

• When you are pinged: the PING pill flashes, the rose shows the pinger’s bearing, and the log says so. The pinger now knows roughly where you are, if the echo reached it, and you can’t tell whether it did. Assume it did.
• When you ping: your own waterfall whites out for a second, and every ship within a very long range now knows exactly where you are.
• Recharge: after a ping, active array needs time to recharge (ACT on the own-ship panel).
• Target strength, by hull shape: a fat cargo hull returns a big echo; a lean warship less; a ghost’s long, skinny hull hardly any. That is why a ghost is built like an old WWII submarine. A destroyer’s ping finds a silent ghost at only about 150 km, inside the ghost’s torpedo reach, so a ghost can close on a convoy without being pinged out first.

11. Gravity wells

Moons and planets pull on every ship, by the real inverse-square law.

• Coasting near a moon puts you in an orbit. Holding a straight line means fighting gravity, which costs propellant and, with flight assist, emissions.
• Bodies block every sensor. A moon between you and a hunter is perfect cover, for both of you.
• Hitting one destroys the ship. Watch ALT.

12. Nebulas

Nebulas are charted clouds. They are on every chart, like moons. Each kind does one thing to your sensors, and its color tells you which:

• The rules are the same for every ship. A hunter in dust can’t hear you, and a hunter in an ion cloud is deaf.
• Entering a nebula drops time compression back to x1 and lights a pill in the header.
• The log reports storm discharges at most once every two minutes per storm. Each report gives a bearing; it is weather, not a ship.
• A burn heard outside the dust gives you away. The drive takes time to spool down, and the near half of a cloud hides you better than its far edge. Cut the drive well inside.
• A scenario may thicken a cloud, or make it glow. A cloud’s static, its dust and an infrared glow (a warm cloud is a bright backdrop, as a planet is) can each be set, so one cloud can blind the array, pings and heat together. HEARD AT allows for the cloud you are in.

Rock fields are asteroid fields and debris clouds, charted as one area because no one can chart every stone. They block signals as dust does, so a boat can hide in one or behind it. Anything moving inside gets struck. Strikes come more often the faster you go, and each one hurts with the square of your speed: at 0.1 km/s you can creep through, and at 3 km/s the field will break you. The enemy takes the same risk, and its captains read the chart: they keep off moons, go around a field at speed, and creep through only below about 0.3 km/s. To practise, the test bench’s The Asteroid Field (data/testbench/asteroid_field.ron, listed with --dev) puts three rows of rock across your way to a beacon, each with one gap.

Debris fields are finer than rocks. They hide you less, and strikes come three times as often at a third of the damage, so a fast pass bleeds you rather than breaks you. Wreck fields are graveyards of dead hulls: small, thick with cover, and full of old steel that swamps magnetic sensors around anything inside.

Belts. A field can be a ring, not a sphere. A belt is a wall from the side and thin from above, and it has a clear hole in the middle. The plot draws it as it lies: a ring from above, a thin line in profile, tilted in the 3-D view. The way past a belt is often over the rim, and a tilted belt stands high on one side and low on the other. Check the profile before you trust the plan.

Warm points. Debris and wreck fields hold still, warm sources about as bright as a boat at rest. They show on the infrared waterfall as straight lines, and nothing marks them. A hull inside the field keeps that clutter as cover while it holds still: up to 12 dB in a wreck field. All of it is gone at 0.3 km/s, because a hunter sorts the lines for the one that moves. This holds for you and for the enemy: if a line on your waterfall is creeping, it is not scrap.

The navigational shield. h, or shield up and shield down, stops strikes up to its rated speed, 0.6 km/s on a boat and 0.8 km/s on a warship. Above that they come through. It draws on the weapons load and shows: it radiates about as loud as the autopilot, and it adds a big field to your hull. So it is a trade. With it up you can cross a field at twice the safe speed and be heard doing it. With it down you creep, or you take the strikes. Enemy captains raise theirs to pass a field at speed, except silent captains, who would rather be struck than heard.

The helm calls fields too. If your course runs into a field faster than is safe, the helm calls a collision course, as for a moon. A tired crew takes more strikes, because nobody calls the big ones in time.

13. Torpedoes

Torpedoes are the main weapon, yours and the enemy’s. A torpedo is a small, fast ship with a warhead: it is heard like a ship, it hides in dust like a ship, and its seeker goes deaf in an ion cloud like any array.

Two kinds.

Fire control aims a shot at a contact from your TMA solution, the way a WWII attack team set up a torpedo data computer. It needs at least a FAIR solution. A GOOD one is usually a hit; a FAIR one wants a spread (salvo 3 s1). The log reports each shot’s course, run and time to impact, and the contacts table counts it down.

Arming distance. Like American WWII torpedoes, a warhead arms only after the torpedo is 40 km from the boat that fired it, so the blast can’t reach the launcher. Inside that distance a hit is a dud. Torpedoes are useless at close range; fire control warns you when the meeting point is too close. It also warns when the run to the meeting point passes through a charted moon or planet: “The run crosses Mere: it will strike it.”

• Boost, then coast. fire s1 burn 30 burns for 30 seconds and then coasts silently: a straight runner coasting is heard only from a few tens of km. Fire control allows for the shorter burn.
• A launch has an edge. A ghost launches cold, and a torpedo’s motor is small: both are heard to about 600 km, no farther than the boat itself. Fire from beyond that and nobody hears you shoot, but a straight runner reaches only about 1,200 km flat out and a homing torpedo about 1,000, so the band is narrow, and a solution is worse the farther off you are. Inside it, the launch is a transient anyone listening can hear, with its bearing. A warship’s tubes are far louder.
• Tubes reload from the magazine, with the same kind if any is left, or the kind you ordered. Reloading takes minutes. See Choosing what’s in the tubes.
• A hit is heard: a detonation, and breaking-up noises if it sank her. There is no sound in space: the crew keeps the old name for the burst of EF and heat as her reactor and power fail and her air vents. With none, the torpedo reached a hull that stayed afloat. See What a hit does. A torpedo that runs out its time without a hit scuttles itself, and the log says so.
• Gravity is not in fire control’s sums. Near a moon, a straight runner curves and misses.

What a hit does

A torpedo does damage in hull points, set by its warhead and how close it passed. Every hull has its own figure, listed in Hits to sink. The damage goes through the same path as a gauss slug, so it lands by direction, knocks systems, can start a fault, and can leave a captain crippled and running. See Damage and Breaking off.

• The pass decides. A warhead does the most at the hull and falls off across the kill zone. At the edge a proximity burst does a quarter of its best. A near miss hurts, and a direct hit hurts far more.
• Small hulls still die to one good hit. A ghost, a hauler, a raider or a freighter goes with one. A near miss can leave any of them afloat, hurt and angry.
• Big hulls do not. A destroyer takes one good hit and is usually crippled by it. A cruiser takes three or four, and a fleet tanker four or five. Bring the salvo the target needs, and count what is left in the racks before you start.
• A hull that lives knows. Its captain knows which way the torpedo came from and goes back down that line. Its mates go to the blast as they would to a sinking, and merchants run. Only a sinking counts for tonnage and goals, so a crippled ship left behind pays nothing.

Sizing a salvo. Fire control’s default spread covers your solution’s error, so that one torpedo in the fan reaches the hull. Against a ship you can sink in one, that is what you want. Against a cruiser or a tanker, a tight salvo on a GOOD solution puts more warheads on one hull: give the degrees yourself (salvo 4 s1 0.2). Once the crew has called a class, the fire control window’s chosen row and check s1 give the crew’s count of good hits to sink it. It is an estimate, and only as good as the call.

Torpedo flaws

Torpedoes fail, as WWII’s did. Each one is rolled at launch for one flaw, at most:

The log reports a dud, a premature and a circular run on your own torpedoes. Fire a spread when it matters, and never wait in the path of your own shot.

Carriers

A carrier is a cold shell with two homing torpedoes aboard. The attack boat carries two, in place of two Mk 1s. carrier s1 40m sends one at S1, to release its torpedoes in 40 minutes. It needs a FAIR solution. A carrier holds for 10 minutes to 6 hours.

A kick motor throws it from a tube, and then it coasts, about as quiet as a mine. When its time comes it lets its torpedoes go, 300 km short of where fire control reckons the target will be. The enemy hears torpedoes on a bearing that leads nowhere near you, and it may run down that bearing. By then you can be somewhere else.

• It knows only what it was told. It hears nothing, and no link reaches it. A target that turns or burns after launch is not where the carrier thinks. The seekers may still find it, and they may not.
• A longer hold is a longer gamble. The longer it coasts, the more an error in your solution grows.
• A short hold may be out of reach. The kick is small: about 2 km/s. If fire control can’t get it there in time, it says so.
• It takes a tube. The order takes the next ready tube. That tube’s torpedo goes back to the magazine, and the tube then reloads as usual.
• It is never a reload. A carrier leaves a tube only when you send it.
• It is not invisible. A pinger can find it, and a crew that hears it may call it a torpedo.

Computer captains don’t use carriers yet.

What a failure tells the enemy. Each one tells a different story. A premature is a blast on the way from your boat, heard for 1,500 km, and enemy captains go to it. A dud that strikes tells its target which way it came from, and the captain goes back along that line. A wide run tells nobody.

The war. Torpedoes improve as the war goes on. In the war campaign, early war’s dud, premature and wide odds are half as high again as this table, and late war’s are 0.6 of it, for both sides. A boat keeps the odds it sailed with.

The exploder setting

You choose how each salvo’s warheads go off.

fire s1 contact or salvo 3 s1 contact sets one salvo. exploder contact and exploder prox set fire control’s standing setting, and the FIRE CONTROL window shows it. Fire control sizes a spread for the setting, so a contact spread is tighter. The computer captains use proximity.

Choosing what’s in the tubes

A tube fires what is in it, and it reloads with the same kind. You can change either.

An order given while a tube is already reloading changes what arrives, at no cost. If the kind you ordered runs out, the tube takes whatever is left. The TUBES line and the fire control window mark an order as 1:MK1>MK2H, and >-- for a tube held empty.

The mine bay does not use the tubes, so an empty tube holds nothing back for a mine.

Choosing the load before sailing

On the title screen, l steps through the loads a boat may sail with, and shows what each one trades. The choice holds for every launch from that screen. Today the attack boat has four besides the standard. A hull without that load sails with its standard one.

External racks. load 2 rack brings a torpedo in from outside the hull. It takes three reloads’ time, it is 10 dB louder than a swap, and it can’t be done inside a cloud. A rack torpedo’s dud, premature and wide odds grow by a tenth for every hour since sailing. The racks never fill a tube by themselves.

Countermeasures

Two things to throw at a torpedo, or at a hunter:

• Static buoy (j, or buoy on the conn): drops astern and roars for 90 seconds, louder than any hull at rest. Anyone listening toward it hears its static on top of everything near its bearing, so targets there fade. A homing torpedo chases the loudest thing in its cone, so it goes for the static buoy.
• Decoy (d, or decoy, or decoy 090 for a course): a drone that sounds and echoes like your ship did at the moment you launched it, and runs on along your course (or the one you give it) for ten minutes. A tracker or a seeker can’t tell it from you.

The CM gauge shows what you have left and the launcher’s reload. Your countermeasures are on the nav plot as ○ (static buoy) and ◎ (decoy) with their seconds left.

Straight runners ignore both. A straight runner goes to a point in space, and its fuze answers only to a real hull. Countermeasures beat homing torpedoes and confuse hunters; against a straight runner, only moving off its point works.

Gauss guns and beams

Destroyers carry a gauss gun; cruisers carry a gauss gun and two beams; a ghost carries one weak beam, its deck gun. Both wear down a hull a little at a time: watch HULL.

Armour depends on the hull and what it is made of. A ghost’s hull is built to damp its emissions, the opposite of armour, so it takes every hit in full. Merchants carry commercial plate, raiders and hunters light steel, destroyers heavy steel, and cruisers ceramic laminate, which shrugs off a beam’s heat best. Armour stops slugs and beams. A torpedo or mine blast is too big for plate, and the hull’s frames answer for it: see What a hit does.

• Gauss gun (g, or gauss s1; rail s1 still works): a coilgun. A row of coils pulls an iron slug down the barrel and fires a burst at 10 km/s, aimed where the target will be and spread across its uncertainty. Slugs are silent in flight, but the coils leave them magnetised: a ship with a magnetometer feels a burst passing within a few tens of km. It gets a log line (MAG Gauss slugs passing, bearing 045°, 18 km), short marks on the rose’s ring and ∴ marks on the plot in the magnetic color. That is a second or two before they pass, too late to dodge, but it tells you someone has a solution on you and roughly where from. The burst itself thumps on sound and flashes on EM. Fire control needs a ping echo from the last 30 seconds or a FAIR solution, and won’t shoot beyond 60 km: very short range, but rapid fire with no long charge, and it chews through a ghost’s bare hull in a single burst. Ping, then fire.
• Beam (lase s1): one shot from a capacitor, which then takes a long time and a lot of power to charge: a cruiser’s two each take 60 s and between them the whole reactor; a ghost’s one takes 90 s and most of its reactor. Light arrives at once, so nothing dodges it. It hits if your aim is good, which takes a sharp bearing and a fresh echo: easy close in, hopeless at the limit of its reach (200 km for a cruiser, 60 km for a ghost). A miss wastes the charge. Its damage falls with the square of range. Every shot lights you up on every ESM receiver for thousands of km, and the BEAM pill shows while a capacitor charges. A hit also heats the target’s hull: a ship under a beam glows on infrared for minutes afterwards, which makes it easier to find again. A beam is light, so the ship it hits sees where it comes from: BEAM ON US from bearing 180, with a flash on the rose. Fire it again and again and the shooter’s bearings pile up.
• Beam against a torpedo: a beam can shoot down a torpedo, and any hit kills it. The sum is how late you find it against how long a shot takes to come round: hold your fire until it is close, because a shot at long range is usually wasted. A cruiser that does stops most single torpedoes, but it has two shots, so a spread of three gets through. A ghost’s deck gun is a lucky shot, no more. A torpedo that coasts in from far off may not be found in time at all.

Why a ghost uses torpedoes. Guns and beams give the shooter away: the thump, the EM flash and the beam’s own light all point back at you. A torpedo, used well, hides where it came from, is hard to see on its way, and does more damage at a stroke than either. Warships are big, loud and heavy; they rush in and use the beam at medium range and the gauss gun close in. That is why a destroyer that has found you wants to get close. A ghost should never let them get that close.

Overloading the guns (overload on, overload off): damage and charging power rise to 130%. Each burst or shot has a 10% chance that something gives. About a third of those hurt the guns. The rest trip the weapons breaker for a few seconds. Use it to finish something, not as a habit.

Mines

Mines wait. They are nearly silent, cold, small and still, and they never go off for their own side. A mine’s blast is in hull points, like a torpedo’s, but a mine has no aim to be true or wide: it does the same at any distance inside its zone.

Finding them is hard, but not impossible. Passive array and infrared won’t find a mine. A ping will, out to about 120 km from an attack boat, but a ping tells everyone where you are. A magnetometer feels one within about 2 km. Found mines show as ✱ in the contacts table (MINE), on the plot and on the chart, where they stay. Charted minefields are drawn as boxes.

Laying mines (lay, lay acoustic, lay magnetic, lay captor): an attack boat carries two of each. A mine stops dead where it is laid; yours are drawn as ✱ in your own color and never go off for you. The MINES line shows what is left.

When one is coming. The log calls TORPEDO IN THE BLACK with its bearing, the TORPEDO pill flashes, and time compression drops to x1. A homing torpedo follows emissions. Burning away makes you louder, so the classic answer is to drop a static buoy, slide off the torpedo’s line, then go quiet and let it take the static buoy. A seasoned captain does the same to you. Against a straight runner, any burn takes you off the point it is running to.

14. Electronic warfare: jamming and ECCM

A jammer is a transmitter that spams static on every band. Anyone inside its cone hears that static on top of everything near its bearing, so contacts there fade and new ones hide behind it.

[!NOTE] The misconception: that jamming hides the jammer. It does the opposite. A jammer is the loudest thing in the sky, on its true bearing. It hides what lies behind it from the ships inside its cone, and it breaks the lock of guided torpedoes. That is all it does.

Who a jammer affects

%% Does this jammer affect me?
flowchart TD
  A{"Am I inside<br/>its cone?"} -->|no| N["Nothing, but I can hear<br/>exactly where it is"]
  A -->|yes| B{"What is it<br/>jamming?"}
  B -->|"my ears"| C{"Do I have ECCM on?"}
  C -->|"no (civilians)"| D["Contacts near its bearing fade;<br/>close in, my displays break up"]
  C -->|yes| E["Most of it rejected:<br/>a narrow sector fades"]
  B -->|"a homing seeker"| F["The seeker loses its lock<br/>and runs on past"]
  B -->|"a straight runner"| G["Nothing: it is aimed at a point"]

Using a jammer

There are two kinds:

• A ship’s jammer (jam 045, jam s1 to follow a contact, jam off; add low, half or full): very directional. It jams only what is inside its cone (20° on a destroyer, 25° on a cruiser, 30° on a civilian set); outside the cone it does nothing. Warships run it at any setting; a civilian set runs at low only. A destroyer captain jams the ship it is attacking; an escort jams any raider it hears at once and moves between it and the traders it guards; and a trader jams the pirate it is running from: the common way for a merchant to break a pirate’s lock.
• A jammer drone (jammer, or jammer 090 for a course): runs off on a bearing and jams all round for five minutes. The ghost carries two.

It costs. A jammer draws power while it is on (10 MW on a destroyer: heat and battery), and a lower setting draws less and jams less (a quarter of the power is 6 dB less). It weakens with range, like any emission. It blinds you that way: its static floods your own array, so you can’t hear anything inside your own cone (the IR telescope still sees heat). And it is a confession: inside the cone it is the loudest thing in the sky, on its true bearing; EM intercept hears it from any side. Use it when you have been found anyway.

What it does to whom. Against pirates and traders, whose civilian arrays can’t fight it, jamming works. Against warships it is iffy: their arrays carry ECCM, which steers a null onto the jammer’s bearing, rejecting part of it and shrinking what it hides. Against a ghost it is weak: a ghost’s ECCM is the best in the fleet.

Choosing the power. The jammer and ECCM each take a share of their full power, not just on or off. jam s1 60% sets a share, low and half are a quarter and a half, and jam + and jam - move it a quarter at a time. The EW gauge shows both settings. The lowest setting is 10%. Less power jams less, draws less and shows less: half the power is 3 dB less. So you can jam just hard enough to beat a seeker, or keep the plant cool on a long run.

ECCM takes power too. At full it draws 0.1 MW for each dB it rejects: 2.5 MW on a ghost. eccm 60% rejects 60% of its rated dB for 60% of the power and EF, and eccm + and eccm - step it. ECCM shares the jammer’s breaker, so a board setting that sheds the jammer sheds ECCM as well. Computer captains run ECCM at full whenever they are jammed.

ECCM (eccm on, eccm off): if your array has it, switching it on rejects jamming (25 dB on a ghost, 12 to 15 on a warship) and narrows the masked sector. It isn’t free: nulling is active electronics, so with it on you radiate a little more EF. Computer captains switch it on only while jammed. On a ghost it is a real trade: see past the jammer, or stay quiet.

Torpedoes: jamming’s best use. Jamming is mostly a defence against guided weapons. The drill: torpedo in the black! Begin jamming! (J, or jam steady then jam s5). Jam it steady: in a look-through pause the seeker can reacquire. A homing seeker inside your cone is swamped, loses its lock and runs on past, so jam toward it and get off its line. That is why a ghost keeps its torpedoes quiet until the last moment. A linked torpedo’s datalink is cut when a jammer’s cone covers it and outshouts the launcher’s link (close to the launcher, the link burns through); it then runs on its last course. A straight runner, aimed by hand, has nothing to jam.

Look-through

A jammer deafens its own ship inside its cone. To listen, a jammer pauses: silent for 5 seconds in every 25, a practice called look-through. In the pause it jams nothing, and your array hears the cone again. Each ship’s cycle is offset, so a group of jammers never pauses together.

• jam look (the default): pause to listen. Use it when you are screening, or running from a ship that might shoot.
• jam steady: no pauses, and no hearing in the cone. Use it against an incoming homing torpedo: in a pause, its seeker can reacquire you. J always jams steady.

Computer captains follow the same doctrine: look-through while screening, steady at an incoming weapon. Jammer drones have no receiver and always run steady.

Being jammed

A jammer over your floor shows as a strobe: a flickering wedge on the rose across the sector it masks, a line out from you on the nav plot, and a wall of static on the waterfall. The EW gauge gives its bearing and how far it stands over your floor. Close in, past about 40 dB, your displays break up: false strobes jump about the rose and plot, and static covers the array’s windows. Jamming raises condition YELLOW. To see past a jammer, switch on ECCM if you have it, or move so the target and the jammer part, or slip out of its cone.

15. Power, heat and signatures

Every ship runs on a reactor and a battery, makes heat, and shows up on more than one sensor. AUTO runs all of it like a sensible engineer, so you can ignore this section and play as before. Or open the engineering window (v) and run the plant yourself: power against emissions, against speed, against sensors, against heat.

Power. The reactor’s output can only change slowly, and it gets louder as it works harder. A reactor that has gone cold must also run through a start before it makes any power: about 90 seconds on a warship, and longer on a merchant. The start can be heard. The battery covers what the reactor can’t yet supply and charges from any surplus. On AUTO the reactor tops the battery up whenever it is under 95%, but once the heat sink is over half full it charges only as fast as the hull sheds the heat, so a warm boat recharges slowly. reactor 100 charges faster and heats the boat. It hums a little while it discharges hard. The drive is by far the biggest load; if supply can’t meet demand, the drive browns out first (engineering shows how far).

The board. Every load has a breaker and a place on a priority list: life support, sensors, tubes, pinger, weapons, jammer, drive. When power runs short, the board feeds that list from the top. The drive and the weapon capacitors can run on part of what they ask for. Any other load gets all of it or trips, and a tripped breaker stays open for 10 seconds. A dark load’s work stands still: tubes stop reloading and the pinger stops recharging.

• board lists the board’s named settings, and board patrol sets one. You never need to touch them: a ship sails on Standard Running, and the crew minds it. A capped reactor also runs its pumps slower, so the hull hums a little quieter: the tighter the cap, the more. Long Patrol caps the reactor at 30% to save fuel, but has no pinger or jammer and answers slowly when the shooting starts. Rig for Quiet saves battery and EF but has no pinger, jammer or reloads, and the drive starves first. Battle Stations puts the weapons first with the plant at full, at a cost in fuel and EF. Engineering’s SETTING line names the one you’re on, and says By hand once you change something yourself.
• S shows what each setting would do on your boat, from her own plant figures at their rating. REACTOR is the most the setting lets the reactor make. DRIVE is the share of full drive it can hold with the battery flat. FUEL is fuel for each second of drive against Standard Running: a reactor burns less per MW at low output, so a gentle burn goes further. SHOWS is how much more the whole boat shows at this throttle. ANSWER is how long the reactor takes to reach full. Choose a row to read its cost, and Enter sets it. board preview patrol gives the same on the conn.
• The chief engineer may mention the board. He speaks in the log, when nothing is happening, and only to a captain still on Standard Running. He raises each subject once, and at most once an hour: tanks under a quarter, or a defect the crew has found that the board can answer. A word from him never slows the clock, and you can ignore it.
• shed tubes opens a breaker, and restore tubes closes it. restore all closes every breaker. Shedding life secures the scrubbers and electrolysis.
• priority tubes puts a load first, priority tubes 3 puts it third, and priority auto restores the list.
• What you power is what you show. Dark sensors make the boat a little quieter and cut its EF, and tubes, pinger and guns show while they draw, even on the battery.

Buses. Two buses carry the loads. Bus A carries the drive, tubes and weapons. Bus B carries the sensors, pinger, jammer and life support. A damaged bus carries less. A failed bus drops its loads until the crew cross-ties them to the other bus, about 30 seconds later. One bus then carries the whole boat at 60% of its rating, so the priority list decides what stays lit.

Generator. A small auxiliary generator (aux on, aux off, aux auto) starts in about 15 seconds. It carries the hotel load and charges the battery slowly, but it is loud and burns four times the fuel for the same energy. On AUTO it runs when the reactor is lost, or when the reactor is down and the battery is under 15%. Silent running turns it off.

Battery banks. The battery is two banks, A behind bus A and B behind bus B. They share the work. bank a off isolates a bank and holds its charge in reserve, at half the discharge rate. A bank that fails loses its charge, and a bank behind a dead bus can’t be reached until the buses are tied.

Fuel. The reactor and generator burn fuel, and tanks do not fill at sea. A reactor has an economical speed: it burns about twice as much per MW at full output as at idle, so a gentle burn reaches the same speed on less fuel, but takes longer. With none left, the reactor goes out and the battery is all you have. A friendly tanker or base fills your fuel and propellant together. Lie within 20 km of it, moving under 50 m/s against it, and order refuel. Drift off and the hoses part; refuel stop lets go. A tanker’s cargo is finite, and a sunk tanker’s fuel goes with it.

Outside the tutorials, a fight finds every ship part way through a patrol: each starts with 40% to 100% of its fuel and standard rations, drawn at launch, unless the scenario sets them.

Bases. A base is huge and doesn’t move. It has six sections, each with its own hull. A hit lands on one section, and twenty direct hits take a section. A lost section takes its share of the fuel store, and the rest of the base stands. Armour turns gauss slugs. A base falls only when its last section goes.

Silent running (b, or silent): shut the reactor down and live on the battery. The coolant pumps stop, so the hull hum drops: an attack boat goes from 110 to 102 dB, which cuts a destroyer’s hearing range on it by more than half. The reactor’s coils go cold too, and the boat’s magnetic field falls to about a tenth, the steel hull’s own: a magnetometer that felt it at 14 km must now come within about 6 to 7 km. The battery lasts about half an hour at hotel load, much less if you burn. Restarting the reactor is a rise in emissions a listener may call as a transient. normal puts everything back on automatic.

Pushing the drive (push, push off): the drive runs at 125% of its rating. You get a quarter more thrust for a quarter more power and propellant, and it is 3 dB louder. The battery covers what the reactor can’t, and the heat follows. Each second at full throttle has a 0.4% chance that something gives, so expect about four minutes. About a third of those failures damage the drive. The rest trip its breaker, and the drive is dead for a few seconds. Either way the push ends, and you must order it again. A boat that has pushed but is coasting risks nothing. Use it to outrun a torpedo, not to save time. Veteran enemy captains push too, when they run from a torpedo.

Heat. All the reactor’s power ends up as heat in a heat sink. The hull sheds some; drifting, that is enough. Burning or charging hard fills the sink. Radiators shed heat fast, but they glow: radiators out show in infrared from thousands of km. On AUTO they come out at 85% and go in below 60%. If the sink fills, the reactor scrams itself to save the ship.

The channels.

All sensors feed the same tracker, so a contact may be held on EF, refined by infrared, and found again by its magnetic field. The HEAR column says which.

EF is the electric field a ship gives off. Space carries no sound, so nothing here is sound. Crews say hear, loud and quiet out of submarine habit, and they mean EF.

What engineering shows: reactor mode and output; battery charge and flow, bank by bank; the generator; fuel and how long it lasts at this burn; heat and the radiators; the load (demand, supply, any brownout); what you are showing the world on every channel, including whether you are transmitting; and the board, when the window is tall enough. A short window lists only what is shed, cut or dark.

16. Life support

Your crew breathes. As on a real submarine, CO₂ is the clock on running quiet: the scrubbers that remove it are pumps and fans, and they radiate.

• Rig for ultra-quiet (ultra, or rig for ultra-quiet): silent running, and the scrubbers secured too. An attack boat drops another 3 dB, to about 99 dB. CO₂ starts to climb, about 0.08% an hour on an attack boat: a full point every 12 hours.
• Blue saves air. On condition Blue, the crew off watch lie still on personal air, and the boat uses 15% less: CO₂ builds more slowly and oxygen lasts longer. WWII crews did the same, sent to their bunks to save what they had. White and Yellow are normal stations, and at war nobody is resting.
• The crew feels it. Past 1% CO₂, or under 19% oxygen, they start to slip; by 4% they are badly impaired. A crew short of air makes worse sensor operators (faint contacts are missed), slower reloads, a slower helm and slower repairs.
• Oxygen comes from electrolysis (it needs power) or from candles (candle, a few carried). With no power at all, the chief burns candles to keep oxygen up, but nothing removes the CO₂.
• The chief of the boat runs the air on AUTO (air auto): scrubbers and electrolysis on. Only an order (scrubbers off, electrolysis off) or a dead plant changes that. normal puts everything back on automatic.
• The COB reports each step of CO₂ past 1% in the log (COB CO₂ at 2.1%: headaches, mistakes creeping in.). The ULTRA pill shows while the scrubbers are off, and AIR 2.1% once the crew is slipping.
• Bad air kills. At 10% CO₂, or 10% oxygen, the crew is lost and the ship with them, in every scenario, at every difficulty, on either side. With the scrubbers off that is about five days on a ghost, so it only reaches a boat that stays down by choice. The COB warns you 12 hours out and again at 2 hours, says what is off (or that the plant can’t keep up), and each warning drops time compression to x1; the air gauge shows it coming. With healthy scrubbers running it never comes.
• Two clocks. To hide you shut the reactor down and live on the battery. A ghost running silent has about 40 hours. Then you must bring the reactor back, and its EF and heat tell anyone listening where you went. Refuse, and the air gets you instead.
• Life support can be hit. It is a damage system like any other. Its health scales how well the scrubbers and the oxygen plant work, so a boat can be quiet, safe and slowly suffocating, and repairing it may mean making noise. See Damage.

Food. A ship carries rations for a set number of days: a ghost 60 standard and 15 emergency, a destroyer 30 and 7.5. Standard rations are sealed meals that keep indefinitely. Emergency rations feed the same in a quarter of the space, and crews hate them. The crew eats standard rations first. The engineering detail shows one bar with each kind in its own colour. For now these are only figures: they run down, and nothing happens when they reach zero.

17. Damage

A hit does more than wear the hull: it knocks one or more of your systems, more for a heavier hit. A damaged system works in proportion to its health; below 25% it fails and stops working altogether.

Facing matters. A hit reaches the systems nearest its side first. From astern it finds the drive, the generator and the reactor. From ahead it finds the array, the pinger and the tubes. On the beam it finds what lies amidships: the buses, life support and the batteries. The nearest system is up to four times as likely to be knocked as the farthest. The crew calls where each hit came from. So a boat running from a gun gives it the drive, and one that turns to fight gives it the ears. This applies to gauss, beams, mines, collisions and torpedoes, so a salvo from astern is the one that stops a ship.

Damage control repairs one system at a time, about 3% a minute, so a badly damaged system takes tens of minutes, and only back to 90%: a full repair needs a dockyard. On AUTO the parties take failed systems first, then damaged ones, most important first (drive, reactor, array, radiators, battery, tubes, pinger, sensors, guns, datalink). repair array puts them on the array instead; repair auto hands the choice back. The log reports each system brought back to working.

Faults that grow. A knock on the reactor, a battery bank, the radiators, life support or the drive may start a fault: a coolant leak, a cell going bad, a bearing running hot. About three knocks in ten do. A fault eats that system’s health, about 2% a minute, until a party has given it five minutes of work. That work stops the fault and mends nothing, so a mend comes after it. On AUTO the parties take faults first. The report marks them GROWING. A bad cell also fouls the air.

Parties show on EF. Repair is electronic work: a party runs test sets, arc welders, powered tools and the equipment it is mending, and all of it radiates EF; an arc welder is the worst, a broadband spark across the radio bands. On a running boat that is 3 dB under the plant’s own EF, which covers it. On a silent boat a party at work can be the strongest emitter aboard, and it can give you away. dc quiet stands them down, and dc work sends them back. Rigging for silent stands them down by itself. So the choice is yours: keep quiet and watch a fault grow, or stop it and be heard.

The damage report (put it in a window with v) opens on the captain’s summary: the hull, what damage control is doing and how long it will take (“On the array (AUTO): working again in about 40 s”), and what you can and can’t do, by job: MOVE, POWER, HEAR, FIGHT, TALK. Press i for the detail: every system with a bar, its health and its state (OK, DAMAGED, FAILED); ◀ marks the system being repaired and ★ your priority. Damage control also reports in the log each time it starts on a system, with its estimate.

The annunciator. A damaged system lights MASTER CAUTION; a failed one, or the hull below 30%, lights MASTER WARNING. It flashes until you acknowledge it with a, and the dynamic DAMAGE window shows what is hurt until you do.

Screens fail too. A window fed by a damaged system breaks up into static: the waterfall, rose, contacts and nav plot as the array fails, engineering as the reactor does. A failed system’s window reads NO SIGNAL. The chart is paper and never fails.

Enemy ships take damage the same way, and their crews repair the same way.

Broken gauges

A knock on a system can break a gauge it feeds. About four knocks in ten do. The gauges and the systems they hang on:

A gauge breaks in one of three ways:

• Dead. The label is struck through and the reading says × NO DATA. Damage control says so in the log. A pill the gauge lights, such as BATT or HEAT, stays dark.
• Stuck. The gauge keeps its last reading, colour and all. Nothing marks it.
• Wrong. The gauge reads live but drifts further off, up to about a third of its scale.

The crew reads its own instruments: the chief counts the battery’s cells and the helm reads the inertial platform. So a crew report, a gauge’s name at the console (battery, helm) and the engineering window’s own meters all read true. When a gauge and the crew disagree, believe the crew.

Damage control replaces a gauge as part of the work on its system, in about four minutes. The parties know of a dead gauge at once. They know of a stuck or wrong one only when you put them on its system: repair battery, and they look the system over and find it. gauges lists what they know, and the damage report shows it as GAUGES. The test bench’s Broken Gauges (data/testbench/broken_gauges.ron) starts with four broken.

Quirks and wear

No two hulls are quite alike. At the start every ship, yours and the enemy’s, rolls its quirks from data/quirks.ron. These include:

• an array that reads a couple of degrees off;
• a reactor that runs loud, or a sweet pump train that runs quiet;
• a drive or battery that never makes its rating;
• a pinger or datalink that drops out now and then;
• a gauge that sticks or drifts (see Broken gauges).

You don’t know your boat’s quirks at the start. The crew reports each one when it bites, or once its system has run long enough for someone to notice. Each report lands in the log as QUIRK, and damage control lists every quirk found so far. A worn system can’t be repaired past its quirk; that needs a dockyard. An enemy’s quirks are real too, and only its behaviour gives them away.

• a yard that did good work on the lagging, or rushed it: the hull sheds heat a quarter faster, or a fifth slower, than the book.

Damage control’s detail view also shows how long each system has been in use: its wear. On most hulls wear is a record only.

Breakdowns on an old boat

A hull from the last war breaks down by age: about once an hour of running, something in use fails for two minutes. You may wait, or jury rig it (u, or jury). A rig brings it back now, and every rig makes the next failure come sooner, for the rest of the exercise. So the question each time is whether you need that system in the next two minutes more than you need a quiet hour later.

18. How the enemy thinks

Computer captains play by your rules. Each has its own sensor picture, built from what its own ship hears; none of them knows where you really are. They fly with the same controls, through crews that take the same time to answer. What differs is doctrine: how a captain decides what to do with what it hears. Doctrine is in data/captains.ron, and the spec sheet lists every captain under Captains.

[!NOTE] The misconception: that the enemy knows where you are once it is coming for you. It knows a bearing, perhaps a rough range. A destroyer charging down your bearing is guessing, and a ghost that moves off that line, quietly, is often lost to it.

Alert states

Every captain is in one of three states. The state decides how it moves, how often it pings and whether it shoots.

%% A captain's alert states
stateDiagram-v2
  [*] --> Patrol
  Patrol --> Search: heard you enough to believe it,<br/>a ping, a sinking nearby,<br/>or a launch (counterattacking captains)
  Search --> Attack: your signal is strong
  Attack --> Search: lost you
  Search --> Patrol: nothing heard for its patience<br/>(5 to 20 minutes)

Sprint and drift. A ship burning its drive is half deaf, so a careful hunter alternates: sprint toward you, then drift and listen. A green captain sprints and never drifts. A seasoned one sprints 90 seconds and drifts 60. A silent attack boat creeps and drifts for minutes at a time. The drift is your chance to move: its ears are open, but it isn’t closing.

Pings. A captain in Search pings only while drifting: a ping sent with the drive burning comes back to a receiver deafened by its own drive’s EF. In Attack it pings freely; close in, the echo is strong enough.

Lying in wait

Every captain knows space has an up and a down. A contact it had solved close by, or had loud and then lost, is near and quiet, and whoever moves first loses. So it comes up on a lost contact slowly, because a ship at speed coasts out of the fight, and when it is close it makes a short burn out of that contact’s plane, up or down as its own coin falls, cuts the drive, puts its nose on the track and listens: for a minute (a green crew) to ten (an attack-boat captain), from the moment it is cold. Only green crews ping while they wait. Hearing the contact again, it attacks; its patience run out, it searches on. It never hides from a contact it still holds, however faint: that one it fights. Expect it: the ship that came down your bearing and went quiet may be coasting cold fifty kilometres off it, waiting for you to show yourself.

After a sinking: the datum

When a ship is sunk, or takes a torpedo and lives, every captain on its side nearby races to the spot, the flaming datum, and searches there. A green captain stops at the wreck. The torpedo came from hundreds of km away, so a green escort searching the wreck is searching the wrong water.

The counterattack

Seasoned and escort captains have learned better. When one hears a launch, a transient together with a torpedo in the water, it:

1. wakes at once, even from Patrol;
2. takes the bearing of the launch, from where it heard it;
3. leaves its station, even an escort’s, and sweeps outward along that bearing line, pinging as it drifts, for up to 15 minutes.

%% The counterattack: hunting the firing point
flowchart LR
  A["Hears a launch:<br/>transient + torpedo"] --> B["Bearing line<br/>from where it heard it"]
  B --> C["Sweeps out along the line,<br/>pinging while drifting"]
  C -->|"echo"| D["Attack"]
  C -->|"nothing for 15 min"| E["Back to the convoy"]
  style D fill:#ffdce0,stroke:#cf222e,color:#1a1a1a

What it means for you: after you fire, your firing point is on a line the escort knows. Don’t stay on it. Move off the bearing, quietly, before she arrives; a ping finds a drifting ghost only within about 150 km.

Shooting back. A drilled captain may answer a launch at once, before she turns. If she hears the transient and the torpedo, and the launch lies within about 10° to 15° of her own level, she fires one or two straight runners back down its bearing from the tubes that bear on it. A boat that came to her height to line up a straight shot sits on that line. Green, silent, pirate and hunter captains never answer this way. Fire from well above or below her, or get off the line as soon as the torpedoes are away.

Torpedo defence

A captain who hears a torpedo first asks whether it is coming at it: a steady bearing and a rising signal mean a collision course. A torpedo aimed at someone else is ignored. For one coming at it:

• Most captains turn away and burn. All but green ones drop a static buoy and a decoy, and jam the torpedo if they have a jammer.
• Counterattacking captains comb the tracks: they turn toward the torpedo, the narrowest target, which is also toward you, and keep pinging.

Escorts and convoys

An escort captain guards the merchants near it:

• On station. With nothing heard, it stays within about 200 km of its convoy.
• Screening. When it holds a threat, it jams it at once and moves between the threat and the merchants, up to 120 km out, so the convoy sits inside its jamming cone from the threat’s side. It may go up to 600 km from the convoy, and 900 while attacking.
• The leash breaks for a counterattack. Hunting a launch bearing, it may go as far as an attack takes it.

Merchants listen too. A convoy that hears a warship or a torpedo makes an emergency turn away and runs. When one of them goes up, the rest scatter flat out from the blast: loud, fast, and hard to catch.

Merchants run; they don’t weave. At condition green they sail straight and true. Evasive patterns were built and tried, five of them, over 60 convoys each. None beat turning directly away and running flat out, which cuts a straight runner’s hits from about 41 in 100 to about 20. A weave is worse, or at best a tie. So a skipper who hears you puts their stern to you and goes, and a stern chase is what you must plan for. A towed hulk or a tanker in orbit can’t run, and stands fast.

In late war, convoys sail with an escort group: two escorts sharing every bearing. See The war campaign.

Flight decks: carriers and their craft

A carrier is the heart of a battle group: the biggest, loudest hull in the fleet, with a flight deck and a hangar of craft, small fast ships flown by two pilots. It can hardly fight on its own. Its craft are its eyes and its reach, and its escorts are its safety. It is the best prize a ghost can take.

Launches. A deck launches one craft at a time, under a minute apart. The catapult and a small drive lighting off beside the hull make a loud transient, and the crew calls it: Launch transients on S1, bearing 312°. Craft leaving a flight deck. A launch tells you where the deck is, and that craft are coming.

Three missions.

• Pickets fly far out, often more than 1,000 km, coast on station and listen. What a picket hears goes over the group’s datalink, so the destroyers have it at once. A carrier keeps a standing patrol of pickets up, and sends more once it is alerted.
• Strikes carry two homing torpedoes out along the carrier’s track on a target, fire from stand-off range and turn for home.
• Screens stay close to the carrier and shoot at torpedoes and enemy craft that come in.

What a craft is like. It burns nearly all the time, so you hear it a very long way off. The same burn deafens it: its small array sits beside its drive. Burning, it hears a quiet boat only alongside. Coasting on station, it hears a drifting ghost at about 50 km, and one running silent at about 20. A destroyer hears the same drifting ghost at over 200 km. A craft’s gauss gun is deadly to a boat it catches close. It is almost impossible to torpedo: it out-accelerates and out-turns a torpedo, and a proximity fuze sees its small hull only at a tenth of the usual distance. A homing torpedo chases the loudest thing in its cone, and a craft is loud, so a carrier’s craft can draw off a homing spread. Straight runners take no notice of them.

Short legs. A craft must keep the Δv to get back to its deck, and its pilots last about two hours. It ranges only within a radius of its carrier, and the radius moves with the carrier. A craft that chases hard burns its reserve and turns for home soon after. A boat outside the radius is safe from craft: know where the deck is, and you know where they can reach.

How they show. The crew calls a craft fighter?, then by class, Fighter or Strike fighter. On the plot, the chart, the rose and the contacts table, a craft wears the top half of its affiliation’s frame, as air tracks do on a military plot: ⋀ hostile, ◠ friendly, ⊓ neutral, ⌒ unknown. The carrier’s own signature is unmistakable once the crew has it: they call it Carrier, and the vessel window lists its flight deck.

How to live through them. When craft come near, go dark: rig for silent running (b), keep radio silence (radio silence), and drift. A craft that passes far off goes on by, and one that passes close may hear you. The real danger is not the craft but the destroyers they call in. A craft finds what is loud; a destroyer finds what is careless. A boat that hunts loud under air cover is found.

When the deck is gone. Sink the carrier and its craft have nowhere to land. They fight on until their fuel or their pilots give out.

In the record. The end screen counts craft shot down (Craft down). Craft are not hulls: they count for neither the ships sunk nor the tonnage. The replay draws them as ⋀, and the debrief says how many flew, how many heard you and how close the nearest came. A craft that lands, or runs out of fuel far from its deck, is nobody’s kill.

Commanding a carrier

A carrier’s captain fights with the deck. Her own hull is the loudest in the fleet and hears a quiet boat only a few hundred km off, so her craft are her ears and her reach. Choose a carrier in the Duel, learn the deck in the guided exercise The Flight Deck, and take a carrier group against a ghost in Flight Quarters. The console takes on the carrier’s colours, Cold Steel, when you sail one; t changes them, and your own come back afterwards.

The deck. deck gives the hangar: each kind of craft, what it flies, how many are ready, and how many are being refuelled and rearmed with the time to the next. It also gives what is waiting to launch and how many are aloft. The DECK row in your status window says the same in short, where a torpedo boat shows its tubes.

Launching. launch picket, launch screen and launch strike s3 put craft in the launch queue. Add a number for more: launch picket 2. A strike flies two unless you say, and it needs a contact with a solution: its pilots are handed your track on it. The deck launches one craft every 45 seconds, from those ready that fly the mission. Every launch is loud, and anyone listening hears where the deck is.

• Pickets fly about 1,500 km out ahead of you, or toward the loudest threat you hold, then coast on station and listen. What a picket hears comes home over the datalink, so you and your escorts have it at once, and two bearings from two places make a cross-fix. When one finds something new, the deck says so: Picket 1, picket, reports a new contact, S4: the craft is 1,480 km out on 012°.
• Screens stay within a few tens of km and fly at any torpedo they hear coming for you, with their gauss guns. Launch one when you hear TORPEDO IN THE BLACK, or before, if you expect one.
• Strikes fly out along your track on the target, fire their torpedoes from stand-off range and turn for home.

Reading the craft. sorties (or craft) lists each craft aloft: its mission, its range and bearing from you, its Δv and the share of its propellant left, its pilots’ time left, and whether it is coming home and why. show deck opens the flight deck window: the bays, the launch queue, and every craft with a Δv bar and an endurance bar, green, then amber under a quarter, red under a tenth. Your craft fly on the rose and the plot in the friendly air frame, ◠, by their short names. On the plot each has a faint ring round you, tagged Picket 1 home 6,200 km: how far out that craft can be and still make the deck in time, on the Δv and endurance it has left. A craft near its own ring is near bingo. layer craft hides the rings.

Bringing them home. A craft turns for home by itself on bingo fuel, when its pilots near the end of their two hours, or when a strike has fired everything. recall calls them all home now; recall picket only the pickets. Launches still waiting are struck off. Craft wait 12 km off the deck and land one a minute; one that came back empty takes 15 minutes to refuel and rearm. A craft still out 25% past its pilots’ endurance is posted lost.

What the deck says. The deck reports through the crew’s reports (reports all, normal or quiet). Launches, landings and craft you recalled are routine, said only at all. A craft turning home on bingo fuel or with empty racks, and a picket’s new contact, are said at normal. A craft lost, shot down or overdue, is said even at quiet.

Tactics. Pickets first: a strike needs a solution, and your own array will rarely give one on a quiet boat. Pickets that burn are half deaf, and one that rushes what it hears empties its tanks within minutes, so keep a reserve in the hangar to replace them. Keep a screen ready, since a ghost that has you will fire from far off. Watch the rings: a craft caught outside its reach is lost. And a carrier that runs from a torpedo pulls her craft’s radius with her.

Breaking off

A captain badly hurt gives up the fight for good. At a hull figure that depends on its crew (about 55% for a green crew, 30% for a veteran one, and nerve moves it), it turns away, stops pinging and shooting, and runs. It leaves its station, its convoy and its friends. A hunter with nothing left to fire and no mates does the same. A captain who sailed already hurt breaks only at a new wound.

You won’t be told. What you have is what the crew hears: the pings stop, the bearing steadies and the contact opens. They may say it looks like a break-off, and they may be wrong. A ship that has broken off no longer counts as tracking you. Some engagements, such as the Duel, count it as finishing the fight. It is still out there, and you can still sink it.

Reading the escort

A hunter’s quality is hidden. It shows in how the hunter behaves, and the crew reports what they notice. These lines appear in the log as SONAR, and in the vessel window as READS AS. Every one is an estimate.

• Habits. After a few pings they call its style. A fast beat with no stopping to listen reads as a green crew. Sprint and drift reads as a drilled one. A slow beat reads as a careful one. A good crew in a hurry can look like a green one.
• Counting. The crew counts the torpedoes they hear and the gauss bursts they feel. Once they have called a class, they set that count against what the book says it carries. A hunter that has fired most of its load may be running short.
• Magazines are counted. Every shot comes out of a real magazine. Early in the war escorts sail short. A hunter that runs dry with no friends breaks off. One with friends stays and keeps the contact for them, so sitting it out can bring them down on you.

Pirates and traders

Pirates prey on traders. A raider hunts what it hears, civilian or not, fires on a FAIR solution from too far, and runs a long way from a torpedo.

Traders run. A trader that hears a pirate or a torpedo turns away at full burn. A civilian trader with a jammer jams the pirate it is fleeing, at the low setting civilian sets allow, pausing every 25 seconds to listen (look-through). A wartime merchant sails dark and jams only a torpedo coming at it, steadily. See Electronic warfare.

Crews

Every ship’s crew takes time to answer: about 3 seconds at the helm and 4 in the engine room for an average navy crew. Merchant crews take half again as long (your own civilian hull is the exception: its autopilot answers at once), pirates a fifth longer; a civilian hunter’s hand-picked crew is a little quicker than the navy’s. A green captain’s crew is as slow as a merchant’s; a seasoned, escort or silent captain’s is a fifth quicker. A slow crew turns late: lead a green escort, and it overshoots.

Captains at a glance

These are the templates. regular and veteran fill out the navy’s ladder between and above green and seasoned, and their figures are in the spec sheet. Who actually turns up is rolled.

Who is in the chair

Every computer-flown captain, and every merchant skipper, is a person, rolled fresh each play. The scenario says what sort of captain to expect; the dice say who you get. A captain of a grade is as strong as any other of that grade by points, but built differently: one is patient and slow to answer, another quick and reckless. You don’t get to see any of this during the fight. You feel it in how they hunt, and find out who it was afterwards.

A sheet holds:

• Attributes, 1 to 10, who they are. Nerve: patience, closing the range before firing, how long they wait in ambush and how long before they give you up. Cunning: leading a target, and how far and from how far they step off the plane. Aggression: speed and burn. Shiphandling: how fast the crew answers.
• Skills, 0 to 5, what they trained. Hunting: coming after a fainter signal. Gunnery: the reach of guns and beams. Countermeasures: how long they keep evading a torpedo. Stealth: pinging less often.
• A speciality, for a warship captain. Ambusher: waits half as long again. Comber: works a torpedo track half as long again. Gunner: a fifth more reach on guns and beams. Listener: acts on less, sooner.
• A flaw, one captain in four. Hothead: shoots on a poorer solution. Glory Hound: chases twice as long, and breaks off from a torpedo too soon. Timid: runs from a torpedo twice as long, and comes on slower. A flawed captain has two more attribute points to make up for it.
• A name, a rank and a line of record. They come from every culture and every gender, because in this war everyone serves.

A sheet leans on the captain’s template; it never changes what the captain is for. Role is doctrine: Line, Silent, Escort, Pirate or Hunter. Grade is how good: Green, Regular, Seasoned or Veteran. A Silent boat that rolls well is a better Silent boat. It doesn’t start pinging.

Most captains are what the scenario says, and a few aren’t. A die moves each one along the grades, and the odds get worse as the war goes on:

Now and then you will meet a really good one. Late in the war, the good ones are the rule.

Reading a captain afterwards. Once the outcome is decided, open the replay (r). WHO YOU FOUGHT lists every computer-flown ship on the other side, with its sheet, and a merchant skipper as one line; WITH YOU lists your own side’s the same way. A captain the scenario fixes, the same in every play, is listed as a standard captain. It was a good fight, or a bad one, and now you know who it was with. A skipper’s sheet is only who they were: it changes nothing a merchant does.

Difficulty

Chosen on the title screen before you sail, and kept with the save.

Nightmare is the bad day every sub skipper dreads: every destroyer and cruiser in the sector, working together, the best crews in the navy, on their best day. It is not for a new captain. It breaks none of the rules in this manual: nobody knows where you are unless they heard you, the dice are the same dice, and when you die you can see why on the replay and the sheets. They are simply better people with better equipment. The trainer says so wherever it counts, in these words: NIGHTMARE: elite crews (reaction ×0.5), finer arrays (ears −6 dB), coordinated, fully loaded.

This reaches the enemy’s navy only. Pirates and civilian hunters come at Veteran and keep their own scale and doctrine. Every enemy warship is:

• Coordinated. All of them are one hunting group, with one shared picture, one pinger and spread search lanes. The datalink’s radio silence is lifted, and you can hear the price of that.
• Veteran, on a full budget, with no flaw.
• Fully loaded. Full magazines, full tubes, undamaged, whatever the scenario says.
• Quick. Crews answer in half the time of the quickest crew otherwise afloat.
• Sharp of ear. Arrays 6 dB finer, and merchants share the ears.
• On their best day. No equipment quirks, no wear, a rested crew and no dud torpedoes.
• Hunting you to exhaustion. No enemy warship gives up. Having lost you, it holds the area of your last fix, the group spread in lanes through it, and waits for your battery and your air. A launch heard pulls them off to counterattack. An escort with merchants to guard keeps its leash.

There is a way out, but you have to earn it. The hold is only as good as the fix. Slip off it unheard and you are out of it: they stay where they last had you. Stay under the fix, cold, and the battery runs out in about 40 hours, the reactor comes back, and they hear it.

Risk against reward. At Nightmare a ghost can usually get away, but the prize means taking the big risk. Measured with a careful scripted skipper over 100 rolls each: against a hunting group, slipping away and never shooting got clear in every one of 100 rolls of Gauntlet and of Escorted Convoy, and even a boat that fought got clear about three times in four. Fighting won 2 times in 100 in Gauntlet and 7 in Escorted Convoy. A lone destroyer is another matter: the script won most of those, by shooting first from far off. The survival and escape figures are a machine’s upper bound, not what a person will get. The script sees everything and answers in the same second, and its judgement never slips. The wins are less tidy: in Gauntlet the same skipper looking up only every 30 seconds won 35 times in 100, because there the outcome swings on the moment of the first shot, not on being quick.

Your crew tires on anything but White, and so does theirs. In a long hold that is a third clock, for the hunters as well as the hunted.

A win at Nightmare stands apart in the records: on the title screen it counts above a win at an easier level in the same iron mode, however quick, and the best says Nightmare.

19. Tactics

The ghost. If you are the weaker ship, and as a civilian you always are, being identified and located is close to death. Stay quiet, stay far away, and let them give themselves away.

• Drift. Burn only when you must, and briefly.
• Never ping unless you are willing to be found.
• Keep a moon between you and danger when you can, or a dust cloud.
• Clear your baffles now and then.
• Listen for transients and pings: they tell you what the hunter is doing.

The destroyer. A warship hunts by finding you, closing in and killing you up close. It pings freely, because it can afford to be heard. A good captain sprints and then drifts to listen. Expect it to come down your bearing when it hears you.

Hunting groups. Warships that hunt together share every bearing over a datalink. Two of them hearing you is a cross-fix: they have your range at once, with no leg change. A group staggers its sprints, so one ship is always listening, and only its lead pings while the others listen in silence. If it loses you, the ships spread out and search their own lanes. The ship with the strongest active array is the group’s flagship and does all the pinging; a cruiser always takes that job. Group-mates know where each other are over the datalink, so they are never contacts: your own group shows on the nav plot and the chart as ▲ with each ship’s name. Against a group, stay far beyond its hearing while you manoeuvre, and slip through the gaps between ships rather than past any one of them. A lone ship’s faint blip is easy to doubt; the same blip from three ships is not.

Captains differ. A green captain charges, pings constantly and fires on a FAIR solution; a seasoned one sprints, drifts, listens, plans an intercept, and waits for a GOOD solution inside 300 km before it shoots. A silent captain flies an attack boat the way you should: it never pings, creeps at low throttle with long drifts to listen, and shoots from up to 500 km on a GOOD solution. Same hull, different danger.

The cruiser. The quietest ears in the fleet (a towed array, though with a wide deaf arc astern), the loudest active array, six tubes, and a big, loud hull that turns slowly. It can’t hide like an attack boat or sprint like a destroyer. It wins by hearing first, shooting from range, and leading a group whose ears feed its tracker.

The attack. Hear first, get a solution by leg changes while you are still quiet, and fire from between the arming distance and a few hundred km. Decide before you shoot what the target will take: one good hit sinks a merchant of ordinary size and only cripples a destroyer, and a cruiser or tanker is a whole salvo. Fire too far out and the target has time to change course; too close and the warhead never arms.

Think in three dimensions. Every display is flat and every habit is too, yours and the enemy’s. A ship that has your bearing comes down it, on the plane it last saw you on. Pitch out of that plane, cut the drive and let it pass: it arrives in your array before you arrive in its, and it leaves with you in its baffles. The enemy knows the move: a captain that had you and lost you close in steps out of your plane and waits, so a bearing that has gone quiet is a place not to be, not a place to go. Clear your baffles up and down as well as round. In a cloud, where nothing hears far and homing seekers are deaf, a straight runner from below is the quiet kill. Crews call the drop itself a Quirk’s Standoff: you hang under the other ship’s plane, cold and silent, and whoever speaks first loses. Naval 2 teaches it.

20. Goals and scoring

Every engagement has goals. Required goals decide the result; optional ones ((optional) on the goals line) earn credit but never fail you. The engagement is won when every required goal is done, and lost the moment one fails or your vessel is.

[!NOTE] The misconception: that sinking the target wins. In many engagements it is only half the patrol. A patrol is what it sank and whether it got home.

Tracked means heard at least 5 times within a minute: one lucky faint detection doesn’t count, though the hunter may come looking. Civilian ships and weapons hearing you never count. A captor mine is the exception. One that hears your boat and fires has detected you, and the end-of-mission box says detected, by a captor mine. One that fires at a static buoy has not.

%% A convoy patrol, goal by goal
flowchart LR
  A["Approach<br/>undetected"] -->|"first shot"| B["Attack<br/>sink three"]
  B -->|"third sinking"| C["Get clear<br/>20 minutes unheld"]
  C --> W["Patrol complete"]
  A -->|"tracked before firing"| L["Patrol failed"]
  style L fill:#ffdce0,stroke:#cf222e,color:#1a1a1a

The replay

When an engagement is over, press r on the end-of-mission box. The replay shows the whole encounter as it really was: every ship’s and torpedo’s true track, which the console could never show you while you fought. It is the after-action report: where you were found, how close the hunters came, why a torpedo missed.

• The map is flat, but its viewpoint moves in three dimensions: a/d turn it, w/s tilt it from overhead to edge-on, [/] zoom, o looks straight down with north up, and c centres on your ship. Every ship stands on a drop line to a gridded reference plane, so height reads at any angle: the third dimension the rose and plot can only give as numbers.
• Lines show who hears whom: amber from a hostile ship that heard you, red from one tracking you, faint from you to the ships you held.
• The timeline runs along the foot: Space plays, ←/→ step, +/- change speed, and n/p jump to the next or previous key moment, marked on the timeline. The strip above it shows detection pressure: the taller the bar, the closer a hunter came to tracking you, and a full bar means one did.

• The debrief beside the map: for each hunter, the most times it heard you in a minute against the 5 it needed to track you, when, and how far off; who heard whom first, and by how long; your closest approach to each ship; your loudest moment and why; how long you burned and drifted. Below it, every key moment: first contacts, launches, each torpedo’s hit or miss distance, what each hit cost the hull and whether it sank her, sinkings and pings. The moments keep their own part of the panel, so a long fight never scrolls the captains’ sheets away; when the sheets are too long to fit, PgUp and PgDn scroll them.

• The ledger in the debrief: what you spent, your tanks and battery at the start and the end, and HIT, MISS and DUD totals. One line per torpedo gives its time, tube, weapon and solution grade at launch (GOOD, FAIR, or BRG for a shot down a bearing), then how it ended: hit (with the share of the hull it cost, and sunk if it finished her), a dud, went off early, decoyed, target turned, no solution, ran wide, circled back, shot down or ran out. The score follows, part by part: goals, tonnage and escape. Last comes the peak detection pressure, with its time.
• The log under the debrief: the lines the boat logged, up to the moment on the timeline, newest at the foot. Step back and you read what it said as it happened; lines from later stay hidden until the timeline reaches them. A short terminal drops the log to leave room for the debrief.

q or r closes the replay.

Watching one later. A finished engagement’s replay is kept automatically, in ghostboat/replays/ beside the saved exercises ($XDG_DATA_HOME, or ~/.local/share), as <date>-<scenario>-<outcome>.ron (date and time in UTC, outcome won or lost). The newest 50 are kept, and older ones are deleted unless you kept them. Saved Exercises on the main menu lists them among the saves, newest first, and Enter opens one. From a shell:

ghostboat --replay ~/.local/share/ghostboat/replays/2026-11-04-125919-duel-won.ron

opens the viewer alone and quits when you close it. A replay holds where everyone really was, so it only exists once an engagement is decided: nothing is saved, or can be opened, while one is running. If the file can’t be written (a full disk, a folder you can’t write to), the log says so in one line and the exercise carries on.

Verdict bands

Every engagement at every difficulty gets a verdict as well as a result: Defeat, Draw, Marginal, Substantial or Decisive. It is scored out of 100 from the goals you met, how much of the enemy’s tonnage you sank and whether you got out. With something to sink, that is 30 for the goals, 50 for tonnage and 20 for getting out; on a run with nothing to sink, 70 for the goals and 30 for getting out. Tonnage counts every ship not on your side, traders included, except one your orders say to spare.

The instructor’s note. After a failed exercise, at every level, the end-of-mission box may carry an INSTRUCTOR'S NOTE: one blunder, and what to try next time. The instructor finds the point the fight turned against you, usually the first time a hunter tracked you, and names your last action that could answer for it: a burn near a hunter, an early ping, holding course on the firing bearing, a shot without a good solution, a straight runner fired on less than GOOD, emptied tubes, a contact held on one leg, or speed through a rock field. A note says no more than the debrief does, and if nothing clear stands out there is no note. A won exercise gets a note for one thing only: a straight runner fired on less than a GOOD solution that missed, so a miss is blamed on the solution, not the weapon. Press i on the box, or point at i the moment, to open the replay at the moment it blames. In the replay, i or a click on the note goes back there, and a ◆ marks it on the timeline. The note stays in a kept replay.

A band doesn’t change whether you won or what unlocks next. It says how well it went: sinking two destroyers and dying is not a Defeat. The verdict shows on the end-of-mission box and in the replay, and goes into your records. At Nightmare, the band is the point.

Tonnage. The end-of-mission box and the replay also show the tons you sank and the tons there to sink: each ship’s dry mass, not counting your own side or a ship you were told to spare. A ship counts as yours if your weapons sank her, or if she was lost to rock, a body or a mate’s torpedo while hunting you: you led her there, and the box lists those apart (2 wrecked chasing you). A ship that wrecks herself on patrol is nobody’s. Tons are raw, as WWII aces were ranked. The level and iron mode are shown beside them and never multiplied in, and a boat that was lost keeps what it sank.

Records. Each finished engagement is recorded: won or lost, the time, the iron mode, ships sunk, hull left, the level, the band and the tons sunk. The title screen shows each engagement’s best, and your heaviest bag and running total of tons; a win in a stricter iron mode beats a faster one in a gentler mode, and at the same mode a harder level beats an easier one. See Title screen.

21. The war campaign

The war is an arms race in three eras, after the Battle of the Atlantic. Every technique arrives with its counter, in the same era or the next: pings against dark running, homing torpedoes against static buoys and jamming, jamming against ECCM, convoy masking against an escort outside the convoy.

The campaign has its own page, War Campaign on the main menu: nine engagements in order. Each opens once you have won the one before it; the first is always open.

%% Who the enemy captains are, era by era
flowchart LR
  E["Early war<br/>green escorts<br/>wreck-searchers"] --> M["Mid war<br/>seasoned and escort captains<br/>counterattack"]
  M --> L["Late war<br/>escort groups<br/>sharper ears"]

Magazines. Early-war destroyers sail with 60% of their load and cruisers with 70%, gauss slugs and torpedoes alike.

War news. The enemy’s guns grow more lethal in 3130, in the middle of the mid war. From then on destroyer and cruiser guns do 20% more damage. An engagement dated 3129 opens with a warning on the wireless, and one dated 3130 with the news. Plan your hull margins by the date.

The era’s changes apply only when you play an engagement from the campaign; the same engagement in free play is the mid-war version. The campaign lives in data/campaign.ron, so you can write your own.

Choosing a boat

The boat setting on the title screen (b) puts you in a different hull wherever an engagement gives you the standard attack boat. All of them do the same job. They differ in how much room for error they give you, and the sheet for each is in the ship registry.

The leaky boat is a self-set challenge: a boat from the last war in place of a modern ghost. The Mk 0 torpedo has no duds, prematures or wide runs, and the hull turns half again as fast as the standard boat. Against that it has three bow tubes and no stern tube, seven torpedoes, under half the velocity change, a louder hull, duller ears, no shield, no mines, no jammers and no ECCM. It is slow to go cold, and something breaks about every hour.

Pick the war to suit. In the early war the old boat fights a matched fight: green hunters with straight runners and no jammers, and merchants that still broadcast. In the late war it is simply a harder boat than the one the hunters were built to catch.

22. Scenarios

Lessons live in data/tutorials/, one folder per track (civilian/, naval/, ghost/), and challenges in data/scenarios/. The title screen lists the lessons under Training and the challenges under Scenarios. Choose one there, or start one directly with cargo run --release -- data/tutorials/<track>/<file> or cargo run --release -- data/scenarios/<file>. A third folder, data/testbench/, holds physics and sensor checks. They are not exercises for a captain: start the trainer with --dev and a Dev item on the main menu lists them, or load one by path (see the development guide).

Tutorials

Challenges

The Scenarios page shows each challenge’s rating, from Routine through Testing, Demanding and Hard to Severe, and lists each kind of boat’s challenges easiest first. The ratings are a first draft.

23. Ship registry and specifications

Generated from data/classes.ron, data/captains.ron and data/tuning.ron by cargo run -p sim --example manual_specs -- docs/manual.md. Do not edit by hand.

Fleet depot (base-depot)

A fuel store with a dock and a beacon, parked where the fleet can find it. It does not move, it does not fight, and every ship in the war needs one sooner or later.

Freighter, bulk (civ-freighter)

A big, slow merchant hull carrying the cargo the war is really about. It has no weapons and poor ears, and it is loud enough to be heard across a sector. Its one defence is to turn directly away from danger and run flat out, which spoils a torpedo shot more often than you would hope.

Hauler, civilian (civ-hauler)

A small civilian cargo ship with a small, hard-pressed crew and an autopilot that does the flying. It is easy to fly and forgiving, and it has no business in a fight. It is loud and half deaf, so anything with a warship’s ears hears it long before it hears them.

Hunter, civilian (civ-hunter)

A bounty crew’s ship, built to run pirates down on the civilian scale. It is quiet for a civilian hull, its crew is hand-picked, and it is patient and hard to bluff. It is still a civilian hull: slow, thin-skinned and far below a warship’s ears.

Freighter, war standard (civ-liberty)

A mass-built wartime freighter: a third of a bulk carrier, welded fast and sent out in numbers. It is slow, has no jammer and carries a green crew, so it is the easiest tonnage in a convoy, and there are always more of them.

Tanker, fleet (civ-tanker)

A vast hull full of propellant, the fuel the whole war burns. It is the heaviest merchant in the black and the slowest to turn, and it is worth a convoy’s worth of tonnage to anyone who can reach it. Escorts put it in the middle for that reason.

Carrier, military (mil-carrier)

The heart of a battle group: a huge, loud hull that carries fighters and strike craft and can hardly fight on its own. Its craft find what its escorts then hunt, and their launches give its position away. Get to it past the escorts, and its craft have nowhere left to land.

Cruiser, military (mil-cruiser)

The flagship of a battle group: the best ears in the fleet, the loudest ping, six tubes, guns and beams. It rarely misses what it holds, and it takes a lot of sinking. It turns slowly and is heard a long way off, so a quiet boat can choose its moment, and its escorts are the real problem.

Destroyer, military (mil-destroyer)

The navy’s hunter of ghosts: fast, loud, nimble and well armed, with torpedoes, gauss guns and the patience to search by sprint and drift. Its strength is that it comes for you, and it rarely comes alone. You beat it by hearing it far off, staying out of its ping, and shooting from outside what it can hear.

Fighter, military (mil-fighter)

A small, fast craft from a carrier’s deck, flown by pilots who take far more g than any warship’s crew, with a gauss gun deadly to a boat it catches near and a drive no torpedo can outfly. It burns nearly all the time, so it is heard from far off, and the same burn leaves it half deaf: it hears what is loud or close and little else. Go dark when you hear one coming, because the destroyers it calls in are the real danger.

Strike fighter, military (mil-fighter-strike)

A fighter carrying two homing torpedoes, which it fires from a range the carrier could never reach unheard. It flies out along its carrier’s track on a target and turns for home once they are gone. It is heard long before its torpedoes are.

Attack boat, military (mil-ghost)

The ghost, a submarine in space: small, cold and very quiet, with sharp ears, four tubes and a thin hull. It fires first, from a solution nobody heard it build, and it decides whether there is a fight at all. Once found it is fragile, and a boat that is heard and then pinged has very little left but to run.

Attack boat, cold hull (mil-ghost-cold)

The attack boat rebuilt to lose heat: a lagged reactor space and a hull that sheds half as much again as the standard build. It goes cold fast, so it can shoot closer and still get away. The price is the magazine, four torpedoes fewer, and no mines.

Attack boat, heavy hull (mil-ghost-heavy)

The attack boat with a thicker pressure hull and a bigger heat sink. It carries the standard load and takes a hit the standard build would not, so it has more room for a mistake under fire. It answers the helm slowly and sheds heat slowly, so it needs a long lead to go cold.

Attack boat, last war (mil-ghost-old)

A boat from the last war, kept in service because the yards are full: worn, short-legged and short of everything. Age left it a nimble hull and an old torpedo that always runs true, and took its stern tube, its shield and its reserves. Something aboard fails every hour or so, and the crew spend the patrol keeping it alive.

Raider, pirate (pir-raider)

A pirate’s converted trader, a little quieter than the ships it preys on and armed to take them. It is dangerous to merchants, and it shoots too soon and from too far. Against a navy ship it is outheard and outgunned, so hear it first and let it waste its torpedoes.

Torpedoes

Torpedo, captor mine. The torpedo a captor mine launches, which arms almost at once and goes straight for what the mine heard. It is short ranged, and it homes on EF. Go quiet and drop a static buoy.

Carrier, torpedo. A cold shell that coasts silently for up to six hours, then lets two homing torpedoes go. The enemy hears them on a bearing that leads nowhere near you. It hears nothing and takes no orders after launch, so it is only as good as your solution.

Torpedo Mk 0, old pattern. The old straight runner from the last war: a simple contact fuze, a plain gyro and nothing to go wrong. It is slower and shorter-legged than the Mk 1 and it hits when it is aimed right. Nobody in the fleet misses the Mk 1’s bad days, and nobody on an old boat has any.

Torpedo Mk 1, straight-running. The straight runner goes to the point fire control aimed at and nowhere else. It is exact against a ship that keeps coasting, hard to hear once its motor stops, and takes no notice of decoys. Any ship that burns after the launch simply isn’t there when it arrives.

Torpedo Mk 2, homing. The homing torpedo chases the loudest enemy its seeker hears, once it has armed. It follows a ship that burns and forgives a rough solution. A quiet target is hard for it to hear, and a static buoy or a decoy can draw it off.

Torpedo Mk 3, linked homing. A homing torpedo its launcher steers until it arms and tracks all the way, carried by ships that don’t mind being heard, which means cruisers. It starts on the right target and the launcher always knows where it is. The link is a transmitter, so the launcher lights up for the whole run and points the way back to itself.

Torpedo Mk 4, fast. The fast runner closes in three-quarters of the time, so a target has less warning and less room to turn. Its hot motor is heard far beyond the boat that fired it, and the line of it points home. It is beaten by anyone who hears it early and moves.

Torpedo Mk 5, cold. The cold runner is barely louder than a drifting boat, so a shot from inside the screen can arrive unannounced. It is slow and short-legged. A target that burns away is gone, and a long shot gives a poor solution time to go stale.

Torpedo Mk 6, defensive. The defensive homer arms at 15 km, where every other torpedo is still a dud, and it runs barely 300 km. It exists for the hunter already on top of the boat. Firing it ends the hunt or tells the hunter exactly where to look.

Hits to sink

Good hits to sink each hull, by the warhead figure in the torpedo table: proximity then contact, or one figure where they agree. A near miss does far less.

Countermeasures

Mines

Mine, acoustic. A mine that goes off when something loud passes close. Ships that burn through a field find it the hard way, and a drifting boat can pass close and live. A static buoy nearby sets it off harmlessly.

Mine, captor. A mine that listens from a long way off and launches a homing torpedo at what it hears. It covers far more space than a plain mine. Silent running gets you very close before it hears anything, and a static buoy deals with its torpedo.

Mine, magnetic. A mine that feels a hull’s field and goes off close by, however quiet that hull is. Silence won’t save you, but a shut-down reactor shrinks the danger a great deal. Keep clear: a ping can find one, at the price of telling everyone where you are.

Passive detection ranges, target drifting

Range in km at which the listener (row), drifting, has an even chance each second of hearing the target (column). Baffles and moons ignored.

Passive detection ranges, target burning

Range in km at which the listener (row), drifting, has an even chance each second of hearing the target (column). Baffles and moons ignored.

Hearing a torpedo

Range in km at which the listener, drifting, has an even chance each second of hearing the torpedo.

Active array ranges

Finds is the range at which the pinger, drifting, has an even chance of an echo from that target. Heard by is the range at which that ship, drifting, hears the ping itself. The gap between the two is why pinging is dangerous.

Ranges on the physical model

These apply in engagements with the physical channels on (Thermal Range, Shadow of the Giant). Each is the range at which the signal reaches the sensor’s detection threshold, in open space, with the listener drifting.

EF array hears a ship, reactor running, drifting.