indeed, it's virtual sailor 7.0. A nice little homemade game of "questionnable" interest once you've played it for some hours lol. More or so, some kind of naval flight simulator counterpart.
I've once made a rather simple nautilus model for training purpose using 3dsmax. Guess i could add some texture to it and import it into SH4 as a standing still NPC unit if you like (after all, we already have the flying dutchman easter egg :rotfl

.But converting the whole thing to a playable unit would involve far too much time for what it would worth