Anyone who's built a ship has likely used a gyroscope at some point as a means to both keep it upright and allow for steering via gyro yaw. Of course real ships don't (usually) do the same in real life.
The main method ships use in order to remain stable is via ballast tanks, which are explained in detail here But to put it simply it fills a tank at the very bottom of the ship (or keel) to lower the center of mass. Since the mass is so low, it keeps the bottom of the ship at the bottom and prevents capsizing.
This can be done in the game via the following method, while will require some careful tuning the result is worth it.
The Buoyancy blocks are placed at the ship's waterline (where the surface of the water will be while it's floating), a set of four will ensure lateral and longitudinal stability. The Ballast Block is made very heavy, and can also have its COM adjusted in Overload to ensure the vessel's overall COM sits well below the waterline.
This creates a counteracting function where buoyancy pulls from well above the COM. This will naturally keep the vessel upright, while also permitting a natural list (or tilt) in turns, which will correct itself upon the vessel running straight.
Speaking of turns, there is a way to make a ship turn naturally like it does in real life, and that involves using a rudder! As simple as putting a wing on a rotator and arranging it vertically. The problem with using just a rudder for ships though is that the hull itself won't direct you through the turn which results in turning without actually going in that direction.
There is a simple solution to that though. Make a copy of the rudder wing, increase its length (relative to the bow and stern) and put it in the middle of the hull (COM) at the bottom. This will naturally ensure your vessel moves straight and ensure it moves in the direction of turning.
Here's a simple diagram showing a side view of a ship with a complete Buoyancy and Rudder setup.
1-Buoyancy Blocks
2-Heavy Ballast Block
3-Rudder and Hull Wing
4-Propulsion Setup
Further note: If you want better rudder control you can increase the (downward) length of the rudder and hull wings, then scale them down to fit. This should improve turning.
@MintLynx Thanks
Nice guide. Surprisingly small amounts of people actually know how to properly do this.
@Chancey21 Well it's simple! Adjusting buoyancy in overload can give you any amount of buoyancy in any size of fuselage block. It's also dependent on mass so the overall mass of a fuselage block will affect buoyancy.
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Fun little fact, hollow fuselage blocks have buoyancy stats in their overload menus so you can adjust it for them too.
Any idea how to get large buoyancy into small spaces?
@TheNightmareCompany There's a couple ways, one is to increase chordScale on a propeller engine. This stops working entirely at a certain depth though. More sure to work is a VTOL engine with the engine above the waterline and nozzles where the propellers are. The third is a Rotator-and-Wing type engine, which works at any depth making it optimal for use in Submarines.
@MintLynx So how do you get propulsion underwater?
My Kiev actually lists slightly opposite of the direction it’s turning, just like a real ship, which is very cool
I did this with my Screamer Powerboat, it makes a world of difference not using a gyro, much more realistic in terms of buoyancy physics.
Extremely helpful, thank you!
Im never going to build a ship but this is very useful to know, thanks.