Welcome aboard and enjoy SUBSIM!
If you have a Facebook account, you can join us!
https://www.facebook.com/groups/25990473292/
If you like Uboats and the Battle of Atlantic, I recommend you SH5 (not Steam version), patched with 1.2 update, and the mod The Wolfes of Steel. Easy install, great and realistic gameplay, constant updates and support, and hardcore in high realism seetings.
For Cold War and actual sub warfare, I recommend Dangerous Waters (similar in gameplay to 688i) or Cold Waters (more arcadish but not easy gameplay). For Dangerous Waters you will need the W8/W10 patch, for high resolution settings. Cold Waters works fine via Steam with W10, same with SH5 (not Steam).
Fitzcarraldo