Remember that MS game, you were air Pirates in the 20's taking on mercenary jobs.
That's what we need for SHIV.
A mad captain gone rogue with a skalywag crew of misfits.
A secret Island base, and all the seven seas to plunder in your pirate sub. Instead of renown you get supplies ,
dry goods, fuel, weapons, maybe a safe port or two to do trade, shanghai new crew
new skins and uniforms for the crew, you could even have a mixed bag of crew, a renegade Uboat officer on an American pirate sub :rotfl: maybe even some German accent ogg. files for a couple of the crew.