I had the original Silent Service on C64. It was my first home computer subsim experience but I got hooked on submarines when I used to play the old electro-mechanical coin op sub games in the arcades such as Sea Devil, U-Boat and Sea Raider etc.
Those were the ones where the machine had a periscope which you used to aim your torps at model ships sailing by inside. This was the days before video games. Great times!!
For those too young to remember these machines, here is a link to an article about one of them:
http://www.pinrepair.com/arcade/seadevi.htm