i guess u can make a underwater athmosphere (u have it in ure athmosphere folder in V5I) and make a lots of small/big spheres with some edited glass textures. i think that would look good. lots of items tho. maybe make a alpha plane? hmm. you will come up with somethng. =)

bout the sub. its a bit ugly for now lol. got a cylinder and sphere and a subdivided rectangle, and some stuff for now.. i dont know exactly where the propellars are going to be yet, but the models are nice (took time).. ill try to hurry up finishing it.