08Outer hull, pressure hull & ring framesStructure
09Vertical payload modulesMission systems
10Sail — masts & sensorsStructure
11Autonomous command coreMission systems
12Weapons room & tubesMission systems
13Spherical bow sonarMission systems
14Main ballast tanksStructure
15Towed array & reelMission systems
II · Power & drivetrain
Room once reserved for people.
Without berthing, galley or life support, the hull wraps tightly around the reactor, turbines and mission systems. The reactor drives turbine-generators and a quiet electric motor turning a pump-jet.
Reactor, turbo-generators and quiet drive — rotating view
A 110 MWt pressurized-water reactor with two steam generators and coolant pumps feeds two turbo-generators; the switchboard drives one large permanent-magnet motor that turns the pump-jet rotor at right. The arrangement is generic.
05Main switchboard — 6.6 kV, electric drive, no reduction gear
06Propulsion motor — 30 MW permanent-magnet, 150 rpm
07Pump-jet rotor — 9 blades, in its duct
08Shaft — short, no gearbox, the quiet reason for electric drive
Pump-jet rotor
Power plantPressurized reactor, 110 MWt
Shaft output≈ 30 MW
FuelHighly enriched uranium, ≈ 93% U-235
Consumption≈ 4.8 g fissile / hr
Metal content≈ 93% high-yield steel
Naked drivetrain — energy to motion
III · Armament
Twenty-eight missiles aft of the sail, four tubes forward.
Four 87-inch payload tubes carry seven Tomahawks each in sealed canisters. Four 21-inch tubes fire heavyweight torpedoes from a torpedo room of about 25 weapons, reloaded from the racks at sea. Choose a system to watch it fire, or open the magazines to see how each weapon reaches its tube. Release stays with humans ashore.
All systems stowed; the boat is submerged
4 × 21-inch Mk 48 tubes · about 25 weapons in the torpedo room · 4 × 87-inch payload tubes, 28 Tomahawks · 14 external decoy launchers
Launchers and mounts
Launcher or mountCountCells or roundsRange classReload
87-inch vertical payload tubes (Block V-style module)47 Tomahawks per tube in a sealed canister (28); or 3 hypersonic rounds per tubeLongIn port only: canister craned in vertically
21-inch torpedo tubes4About 25 weapons in the torpedo room, four of them in the tubesShort to mediumFrom the racks at sea: tray and hydraulic rammer, minutes per tube; the room is filled in port through the loading hatch
6-inch external countermeasure launchers14 (7 each side)1 decoy eachVery shortIn port, outside the pressure hull
Tomahawk Block V, long-range land attackIn service
Tomahawk Block Vb, alternative payloadIn development
Conventional Prompt Strike, hypersonic, 3 per payload tube (Navy target 2029)In development
Nuclear sea-launched cruise missile SLCM-N (by law, no later than 2034)In development
Anti-ship
Maritime Strike Tomahawk, Block VaIn service
Encapsulated Harpoon UGM-84, from the torpedo tubes (limited, refurbished)In service
Mk 48 heavyweight torpedoIn service
Anti-sub and torpedo
Mk 48 Mod 7 heavyweight torpedoIn service
Mk 48 Mod 8In development
Low-cost heavyweight torpedo (offers sought 2025)In development
Mk 58 Compact Rapid Attack Weapon, anti-torpedo (multi-packed in a tube)In development
Mines and vehicles
Mk 67 submarine-launched mobile mineIn service
Mine-laying UUV, tube-launched (prototype 2026)In development
Tube-launched medium UUV, launch and recovery (demonstrated 2023)In service
Tube-launched mini-UAVIn service
Expendable acoustic decoys, ADC familyIn service
Systems are named by US Navy designation. Sequences follow public descriptions at animation pace; the booster is shown lighting at the surface, and the salvo spacing is illustrative. Sources and checks are listed in BUILD_NOTES.md.
IV · How it is put together
Cylinders outfitted on end, four sections joined.
Steel plate is rolled into pressure-hull cylinders, which are outfitted standing on end and slid full of deck packages before four super-sections are joined and closure-welded; the sail, planes and pump-jet go on last. Today one boat takes about seven years.
Thick steel plate is rolled and welded into short pressure-hull cylinders.
Standing on end, cylinders receive tanks, pipe and machinery from overhead cranes.
Bow, operations, reactor and engine-room sections are joined and closure-welded.
The sail with its masts, the control surfaces and the pump-jet go on.
The boat floats off the dock and makes its first dive at sea.
I
Plate rolled into hull cylinders
II
Cylinders outfitted standing on end
III
Four super-sections joined
IV
Sail, planes and pump-jet fitted
V
Float-off, first dive, sea trials
V · Specification
Concept specification.
Design specification for the autonomous attack submarine.
Length overall
115 m
Displacement (submerged)
≈ 7,800 t
Power plant
Pressurized reactor, 110 MWt
Consumption
≈ 4.8 g fissile / hr
Core life
Life of ship
Speed (submerged)
30+ kn
Propulsor
Pump-jet
Sonar
Spherical bow array
Payload
Weapons room + vertical modules
Endurance
Limited only by maintenance
Electric output
≈ 33 MWe, 30% steam cycle
Shaft output
≈ 30 MW, quiet electric drive
Reactor load at 30 kn
≈ 100%; 12% at 13 kn patrol
Battery buffer
4 MWh; 1 hr at 13 kn patrol
Metal content
≈ 93% high-yield steel
Crew aboard
0
Onboard compute
Four AI modules inside the pressure hull
Modules4 AI modules (navigation & mission; sonar classification; ship control & plant; verifier) + 2 certified safety controllers
AI throughput20,000 TOPS total (4 × 5,000, INT8 / FP4 sparse)
Memory4 × 128 GB LPDDR6, 600 GB/s per module
Power draw400 W compute; ≈ 0.7 kW with sonar processing front-ends and 4 mast cameras — 0.002% of the 33 MWe plant
Process node2 nm-class SoCs; safety controllers on a mature 16 nm node, 15-year supply
RedundancyEvery sensor is wired to both module pairs. Each module is primary for its own job and hot standby for its partner, and any one can bring the boat to a safe depth and speed. The verifier checks every manoeuvre independently. A software fault can never drive the submarine outside its certified safe envelope: two SIL 3 controllers hold reactor protection, depth and ballast on their own depth gauges, plane and rudder angle sensors, shaft encoder and reactor instruments.
SensorsSpherical bow array, flank and towed arrays, 4 mast cameras (visible and thermal) on an automotive Ethernet camera switch, navigation radar at the surface, inertial navigation, 2,000 plant sensors
LinkVery-low-frequency and satellite when at communication depth; the boat carries its mission plan and rules and follows them between contacts. Motor drives close their own current loop at 1 kHz; every safety loop closes aboard.
Service lifeThe boat serves 33 years on one core. Compute is a line-replaceable unit, swapped at mid-life.
A submarine spends most of its patrol out of contact, so it carries the whole mission plan and the rules that bound it, and an independent verifier module must agree before any manoeuvre. Weapons release is never an onboard software decision; it stays with humans ashore. Reactor protection and depth control sit on certified controllers that no software update can reach.
Today vs IC
Power and crew: today’s attack submarine beside the IC design
Today · nuclear attack submarineIC design
Layout115 m, ≈ 7,800 t submerged; torpedo room, berthing and control room forward of the reactor115 m, ≈ 7,800 t; no berthing, galley or control room; weapons room, vertical payload modules and autonomy core