Sea Wolf is the first submarine video game. It had large success mainly because of its excellent periscope feature. The player have to look through the periscope and move left and right to aim at ennemies and launch torpedoes.

Your torpedoes come from the bottom of the screen and must reach the top to sink as many ships as you can in a limited time period. But there are also many floating mines underwater which will stop your torpedoes...

Great game that inspired many others.