So this is actually the start of the submarine I was working on. I have currently given up until Gibbed updates the filelists again since most of the variables I was working with are not yet un-hashed.
This is a basic boat that dives underwater. The thrust and dive controls are binded to the same key due to a limitation, but its easy to get used to.
Try not to back up while above water as the boat will most likely flip (The thrust is so large since it has to be able to dive underwater).
You'll need a black market mod to spawn this as the AI boats will be underwater and you cannot get in underwater.
Just drop the .eez file inside you dropzone folder and then start the game. (Create the folder if you don't have one)