I was thinking something similar to this earlier today.
SH5 needs an Intel O to brief you in an HQ Office....outside of the sub pen. Your office would be complete with a map of your kills, a Crew information, Boat information and a newspaper (kind of similar to B-17 the mighty Eight if you remember....but better
)
Have a separate Intel Vault with a guard and special access only to get inside. Inside have a mock up of the north Atlantic with active convoys reported positions ( know it doesn't matter to you and your boat since your in port). Intel O can brief you on new technologies and tactics, assessed enemy strength..ect.
I guess i want time in port to mean something.... but of course i'm dreaming