In Boat Simulator 2, you can learn how to drive 4 types of water vehicles including Submarine. Also 2 amazing landscapes are wating for you. Have fun!
How to play Boat Simulator 2:
Use WASD/Arrows - drive, V - change boat, C - change camera, RMB - move camera, Wheel MB - Zoom In/Out, H/J - hide control instruction / hide control sliders. For Submarine there is Slider to control depth.