Can't speak for the devs here but given that the engine exhaust comes out of the rear part of those tubes, it's safe to assume those are the actual engines/combustion chambers for the ship's drive.
That being the case: where physically would the torpedo tubes fit then?
[ sci·am·ach ]
/sīˈamək/
A simple, angry man casually working his way through life on a personal quest to acquire copious amounts of street cred.
