Everyone pretty much knows, or should know they can be modeled. Silent service has been around for 20 years or more. The problem as I see it would be as outlined above, the diving. The AHII model has had a lot of problems with GV's spawning in trees & falling into holes in the terrain etc. It was explained that they "drop" from above onto the terrain when they spawn, a sub would be an easy addition if it was to be a surface vessel only, but diving with the current structure of the game? Like I said, I'm no programmer but I see where that would be a problem with the current structure of this game.