I've been playing sims for years, usually WW1 and WW2 air simulators.
About submarine ones, I mostly play SHII, also a bit of SoF and I'm currently in progress of finishing the campaign that I started several years ago (5 or 6). I recently discovered a savegame of it...so I'm now again on deck.
Perhaps when I finish the campaigns I'll switch to more modern ones...but before that I must polish my style (probably more suited to torpedo boats than to subs
) and learn better manoeouvres.
Also, I like a lot Napoleon Total War's naval combats, but there aren't subs there, just powder, sails and swords
PS: Also, since I started playing, I've learnt German, at least the minimum to understand the crew. Hearing the order in OV and knowing what they are saying has been a great improvement in gameplay.