Barotrauma - Best Submarine
If you are looking for the best vessel to sail in Barotrauma, here are two suggestions.
Barotrauma offers a range of submarines that you can use. Below you will find two of the best. So if you are looking for a boat for yourself, I recommend considering these options.
Humpback
In case you are playing with a smaller crew, the best option is definitely the Humpback. Despite its relatively compact size, it has everything you need on board to function efficiently - including a fabricator. In addition, it has cannons that cover most of its immediate surroundings. You can additionally fill the remaining gap with another weapon.
The most significant downside of the Humpback is that the engine and reactor share one room. If somehow a fire breaks out in that section, you will be in big trouble.
Typhon 2
If, on the other hand, you are playing in a larger group then Typhon 2 will be a good choice. It has a very convenient room layout, in which each crew member has their own corner. In addition, like on the Humpback, the guns are spaced in such a way that as much of the ship's perimeter as possible is covered.
The problematic part of this ship, on the other hand, is its huge front, which cannot always be defended effectively. It covers the middle decks and creatures can easily break through it, almost immediately getting to the bridge. Speking from experience, however, the situation with enemies tearing through the ship does not happen here more often than on other ships.
The Iroh, the best that the mods offer.
If you want to use mods, you can find The Iroh in Steam Workshop. Personally, this is the best ship you can sail in Barotrauma. It has a very clear room layout and well-placed turrets.
The best ship is still largely a matter of preference. I personally consider the above ships to be the best that the game itself offers. However, if they do not appeal to you then you can always test other boats as well.