Raise all a sunken ships from the bottom of the sea to the surface. Before you can raise them, however, you must release them. They are chained to the bottom of the ocean. You've got to shoot mini cannon balls to break the chains and release all the ships. Do it before time runs out and you level up. If not, you fail! Shoot at the question mark to get extra points or ammo. How many levels can you shoot your way through? Have a good time manning the Green Submarine!