There were some fires but it wasn't on fire. More like left overs from the fight. To add smoke and some dramatic lighting. *pose*
Kitty would have suggested that Tony try welding the hole in the ship back together, I think. Enough so the ship wouldn't sink immediately anyway. She wouldn't be sure that was even possible but she'd suggest it.
Depending on location, the ship could sink either rapidly, or slowly. Occasionally it might even be able to limp into a port.
There's also the question of 'wtf did torpedo's come from' that ought to be investigated, but that's more of a longer term thing.