Source: \Compute! – Issue Number 82 – March 1987
Sub Battle Simulator was released by Epyx for various home computer systems in 1987. This particular ad from the March 1987 issue of Compute! mentions the Commodore 64, Apple II, Apple IIgs, Atari ST, Macintosh and DOS. You could get a demo disk for any of those systems for $1.50 each. According to Wikipedia, it was also available for the Amiga and Tandy Color Computer 3.
Commodore 64
Sub Battle Simulator recieved somewhat mixed reviews. Most reviewers agreed that it was a fun game (despite some lengthy periods of inactivity) but there some complaints about lack of realism. In Sub Battle Simulator you can captain various types of submarines on a variety of missions for both the the Germans and the U.S. during World War II. If you were just looking for a submarine combat game you could just pick up and play then this one wasn’t a bad choice but if you were looking for a more accurate and detailed simulation then there were better options. I guess submarine games were more popular back in the 80s.
Apple IIgs
If you do want to give it a try, there are a number of versions to choose from. I’m not really sure what the best one is. My guess is that the Atari ST, Amiga and Apple IIgs versions are the best but Epyx usually did an excellent job with the Commodore 64 versions of its games so I wouldn’t count that one out. There aren’t any re-releases or sequels to this game. Whichever version you choose to try you’ll have to track down some original disks and the right equipment or use emulation.