Welcome to Subsim, Brian.
This is the number one naval sim forum. If you can't get help here, you can't get it.
My fave modern sim (no longer modern) is FAST ATTACK. I have also played 688 but gave it up as there is very little to see. It would have been good to have a better internal sub, as SH does, and maybe crew. The state of programming and graphics of the time didn't allow it.
I am sure there is more for you on the threads dealing with those games you mention. Use the search feature too, searching for a game title like '688' to drill down to what you want.
Luck
