Naval simulation · in development
A naval simulator where every sailor has a job.
open-ship simulates the whole ship: every machine, every compartment and every member of the crew, each one an individual with a history, skills and work to do. The first ship is HMS Violet, a Flower-class corvette of the Battle of the Atlantic.

The crew are not scenery.
Most naval games are about gunnery and graphics. Their ships carry hundreds of sailors who do nothing; they exist to be killed.
In open-ship the crew run the ship. The watch on deck steers and keeps lookout, the engine-room watch answers the telegraph, the cook feeds the messes and the watch below sleeps. The aim is that everything that keeps a ship's company busy, from manning the guns to swabbing the deck, is simulated. You command as the captain, or take the place of anyone aboard.
Every sailor
Named individuals with a rate, a post, skills and a body. They keep watches, sleep, eat, tire, get cold and wet, feel fear and learn from drill.
Every machine
Boilers, the triple-expansion engine, shaft, propeller, pumps and rudder, modelled physically, with a watch standing by them.
Every compartment
The ship is a graph of spaces, doors and hatches. Water comes in through a hole, spreads, is stopped and pumped out, and changes how she floats.
Orders and reports
Orders pass by voice pipe, telegraph and messenger, and are repeated back. The captain knows only what he is told: late, and sometimes wrong.
The simulation today
The simulation runs in full today, driven from a live dashboard. Here, in the middle watch, she is holed in the engine room at twelve knots. The engine-room watch reports it, the officer of the watch calls the captain and closes up damage control, and the pumps start to win.
Working now
- Hull motion in wind and waves, calibrated against sea-trial data
- Steam propulsion, from boiler to propeller
- Turning and manoeuvring as the Flowers did on trial
- A full ship's company with watches, sleep, meals, fatigue, skills and stress
- Orders by voice pipe and engine-room telegraph, repeated back and reported
- Standing orders and night orders for the officer of the watch
- Flooding, watertight doors, damage control and pumping
- Cold, wet and seasickness
- Injury, first aid, triage and the sick list
- Weather that develops over hours
- Command as the captain, or as any member of the crew
- Deterministic replays and saves
Built from the sources
Every number in open-ship comes from a source or is marked as an assumption: builders' plans and lines, sea trials, wartime instructions and drill books, and the accounts of the men who served. The ship's physics are calibrated against her own class's trials.
The Flower-class corvette comes first because she is small and simple: one shaft, two boilers, a crew of under ninety.
One ship first, then the fleet
Ships are data in open-ship: the code models boilers, engines, compartments and people, and each class, ship and navy is a composition of them. Violet comes first and stays the only ship until the 3D client is ready. The plan after that:
- 1HMS Violet (K35)in development Flower-class corvette, Royal Navy, 1941
- 2HMS Arabis (K73) A second Flower: a sister ship with her own fit and history
- 3USS Saucy Arabis again, lent to the US Navy in 1942: the same hull under a second navy
- 4Other Flower-class corvettes Further ships of the class, their refits and their navies
- 5HMS Wanderer (D74) A V&W-class destroyer: two shafts, turbines, a larger ship's company
- …The Battle of the Atlantic, then beyond Other small warships of the Atlantic, then warships in general, then ships in general
Multiplayer
A long-term goal: join a friend's ship as one of her crew, or sail your own ship in the same world.
Support open-ship
open-ship is an independent, one-person project funded by its supporters. Donations go directly into development.
Support on Ko-fi