When one of my multiplayer sessions degenerated into a 'screw it, let's surface and blast them' affair (we nailed four destroyers BTW), I actually rammed a destroyer and while my boat was riding over the mid section of the destroyer, I launched a bow torpedo for a laugh, it just pooped out and then sank.
What a disappointment, I thought I was in for a ringside seat on the mother of all explosions.
I demand that the devs fix this at once! - That's a joke by the way, before the flames arrive.