open-ship
Open source In development

A naval simulator where every sailor does his bit.

Begin in the Battle of the Atlantic aboard HMS Violet, a Flower-class corvette. Every sailor has a name, a rate and a duty.

Explore the simulation
Looking down from the crow's nest over HMS Kelvin's bridge and forecastle: officers at the compass, signalmen at the lamps on the bridge wings, and the crews of the two forward twin 4.7-inch guns
HMS Kelvin at sea, September 1940, seen from the crow's nest. Photograph: Imperial War Museums (A 659). Colours are interpretive.

The crew are not scenery.

You command as the captain and can take control of any man aboard. Each sailor has a job, and the ship depends on him doing it.

The helmsman follows orders from the bridge. Stokers tend the boilers, the artificer answers the telegraph, and the ASDIC operator listens. Off watch, men eat and sleep before their next turn on duty.

The aim is to simulate every part of life aboard, including gunnery and depth charges as development continues.

Six sailors in steel helmets loading a 4-inch gun on the forecastle of a corvette at sea
The gun's crew of HMS Vervain, a Flower-class corvette, loading her 4-inch gun, July 1942. Photograph: Imperial War Museums (A 10666). Colours are interpretive.

Every man

Every sailor has his own skills and duties. Watches, sleep, meals, cold and fear affect his work. Practice improves it.

Every machine

Boilers, engines, pumps and instruments follow their physical limits. A boiler short of water can burst. A flooded generator cuts the electrical supply.

Every compartment

Floodwater spreads through openings, loads the bulkheads and changes the ship's trim. The repair party closes doors, plugs holes, shores bulkheads and pumps water out.

Orders and reports

Orders travel by voice pipe, telegraph and messenger. Reports can be late or wrong. The captain acts on what he sees and what his crew tell him.

The simulation today

The simulation runs through a text dashboard on macOS and Linux. A graphical client with walkable decks comes next.

Shown here: Violet's engine room, four minutes after a breach during the middle watch. The bridge has called the captain, sent the repair party and put both pumps on the flooding.

The open-ship dashboard on its damage-control tab: the ship in profile with water in the engine room, the watertight openings, the repair party and the pumps, and the reports as the bridge received them

Working now

These systems run today and are visible on the dashboard.

The ship

  • Hull motion in wind and waves, calibrated to sea trials
  • Steam plant from boilers to propeller, including low-water boiler failure
  • Turning and manoeuvring calibrated to sea trials
  • Flooding, watertight doors and hatches, bulkhead failure and shoring
  • Steam pumps, suction lines and machinery lost to flooding
  • Capsizing and foundering

Her company

  • Individual watches, sleep, meals, fatigue, skills and stress
  • Cold, wet clothing, seasickness and scalds
  • Injury, first aid, triage and the sick list
  • Fear of flooding, with rare, brief panic
  • Damage-control and first-aid drills that build skill
  • Control of any crew member, with succession if the captain falls

Orders and knowledge

  • Voice-pipe and telegraph orders, readbacks and mistakes
  • Standing orders and the captain's night orders
  • Delayed or mistaken reports that shape the bridge's knowledge
  • Magnetic variation, gyro failures and steering by compass
  • Navigation plots from measured motion and contact reports
  • ASDIC with noise, reverberation and thermal layers, checked against wartime ranges

World and tools

  • Changing wind, sea, cloud and visibility
  • Sun, moon and natural light
  • Bit-exact saves and replays across macOS and Linux
  • Data-defined ships, navies and crews, with mods and ship packages

Built from the sources

Ship plans define the hull. Sea trials establish performance. Admiralty manuals describe watches, orders and drills. Crew lists supply names, and published research informs fatigue, seasickness and heat loss.

Data is labelled by origin: a source, calibration, standard physics or an assumption. Gaps stay visible so better evidence can replace them.

On a corvette's open bridge, a signalman sights along a telescope while two officers in duffel coats keep watch, one with binoculars
The captain, first lieutenant, and a signalman on the bridge of HMS Vervain, a Flower-class corvette. Photograph: Imperial War Museums (A 10667). Colours are interpretive.

  • Plans and trials

    Original drawings define the hull and internal spaces. A sister ship's 1940 trials provide speed, power, fuel use and turning performance.

  • The Admiralty's manuals

    The Manual of Seamanship covers watches, orders and damage control. Gunnery and stokers' manuals describe work at the guns and boilers.

  • Men who were there

    Corvette officers' memoirs record daily practice and emergencies, from a captain's night orders to a boiler explosion at sea.

  • Human physiology

    Published studies and standards underpin seasickness, sleep, alertness and the body's loss of heat.

One ship first, then the fleet

Violet comes first: one shaft, two boilers and fewer than ninety crew. Other ships will use the same systems, configured through data. Once the graphical client is ready, the fleet grows in this order.

  1. 1
    HMS Violet (K35)in development Flower-class corvette, Royal Navy, 1941
  2. 2
    HMS Arabis (K73) A sister ship with her own fittings and history
  3. 3
    USS Saucy Arabis in US Navy service from 1942
  4. 4
    Other Flower-class corvettes More Flowers, with different refits and navies
  5. 5
    HMS Wanderer (D74) A V&W-class destroyer, with two shafts, turbines, and a larger crew
  6. …
    The Battle of the Atlantic, then beyond Atlantic escorts, larger warships and eventually ships of every kind
Aerial view of the battleship HMS Nelson at anchor, with two Queen Elizabeth-class battleships and two London-class cruisers anchored beyond her
HMS Nelson off Spithead for the Fleet Review, May 1937. Photograph: Imperial War Museums (MH 4). Colours are interpretive.

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An independent, open-source project built by one developer. Your support will help fund its development.

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