Sailing and submarines: afloat, under sail, under the sea.

Floating

• A ship floats by her displacement: the blocks she is made of, plus the dry air they enclose below the waterline, weighed against her own weight. A wooden hull floats; a solid lead one sinks.
• The sea comes in wherever it can reach from outside below the waterline. It fills a layer of cells at a time, so a holed or overloaded ship settles, floods and goes down rather than sinking at once.
• A ship with more heavy material than she can float will sit lower in the water. Keel ballast brings her level, and a ship with trim ballast forward can be set straight.
• A ship that touches the ground runs up onto it and rests there. Wheels can roll up a step of about 1.1 m.

How a sea ship moves

Power	What drives her
Sails	A mast with sail blocks catches the wind. A wooden sailing ship needs no fuel at all.
Paddles	Paddle wheels at her sides, as on the Riverqueen steamer.
Screws	Propellers at her stern, turned by an engine.
Crew oars	With no sail, no paddle and no engine working, her crew can row her, slowly.

Engines run on fuel. Each engine has its own bunker, and a barrel of petrol or diesel fills about 45 units of it. Coal burns fastest, then steam, then petrol, then diesel. A steam engine also needs water in its boiler. When an engine runs dry she stops, while sails and paddles still drive her. Fill an engine's bunker by putting fuel in her tanks at a port or from the bag.

The helm steers her. Her rudder sits over her screws or at her stern, so she turns best with her screws turning. A ship with a bigger rudder and more engines turns faster and handles more easily.

Sea ships in use

• Small boats (the Wayfarer Skiff and the Kelp Runner Sloop) are for shallow water and crossing a bay.
• Pirate and sailing ships (the Black Gull Brigantine and Sovereign Galleon) carry cannons along their sides and have a hold below decks.
• Steamers and yachts are for comfort and speed on the open water.
• Warships (the Harrier destroyer and the Anvil battleship) have turrets that a Fire Control Director lays from the bridge. The battleship is a true-size 270 m ship and needs a wide sea to sail in.

To launch a ship from the Store, place her where you want her. The game looks for open water near you that is deep enough for her keel and clear above for her masts. It tries rings round you, starting in the direction you face.

The Deepwater Nautilus

The Nautilus is the game's submarine, a black hull on an iron keel. Her portholes let you see out, and her conning tower has a hatch on top.

• Diving: crouch to take water into her ballast tanks and go down.
• Surfacing: jump to blow the ballast and rise.
• Holding depth: let go of the controls and she holds her depth.
• Getting aboard: climb the rungs up her side from the sea to the top of her hull, then go down the hatch in the conning tower.

A submarine has a crush depth. Deeper than that, her hull groans, then cracks. A cracked part lets the sea in, and the sea keeps coming until she floods. Keep her shallow, or dive only as far as her hull will take.

Damage at sea

A ship that loses too much of her weight in blocks goes critical below 40 per cent of her integrity. A ship whose helm, engines or fuel are gone, and whose hull is well hurt, goes critical too. She burns for a few seconds, with sparks and failing controls, and then cooks off. A ship at sea breaks her back, and any magazines she carries go with her. A pirate ship that strikes her colours becomes a prize, and she takes much more punishment before she goes down.

If you get the helm, engines and hull back into shape before the fuse runs out, she recovers. Repair her at a port.

See the fleet for every sea design, and the Shipwright to build your own.

← Back to the wiki · Last updated 25 October 2026. Mantlenaut is in alpha, so things change.