I like this one even better than "Silent Service" or "Das Boot"...
It's fun. The missions are diverse (intercept a convoy, rescue a parachuter, destroy a target, etc). The gameplay is easy enough to be fun without having to consult a 500 page manual every few seconds but has all the necessary elements to make it realistic. And your log - you save your log with a list of all of the Japanese ships you've sunk including their tonnage etc. I still enjoy this game today! The atmosphere was sooo cool for the time being.
Well, graphics and sound don't match up today. And the game will get repetitive - there's only one island chain and the same (although diverse) missions all over again. I would have really liked a storyline-based campaign mode or a mission- and scenario add on.
The Bottom Line
Good luck finding it anywhere, but if you do odds are you'll enjoy it. *I* did, and I usually *hate* simulators with a passion.