[Hooston]

Onkel Karl would say "be more aggressive". Only in German. Probably.

You have three torpedo tubes, that's one each. They are all pretty helpless against submarines. I think historically Southampton class had a few depth charges for scare effect, and at a pinch could launch its Walrus to depth charge you; so that might be a threat, but I've never seen cruisers attack in game.

The liners and auxiliary cruisers more often than not go down with a single hit and heavy cruisers and large light cruisers seem to also sink very readily with a single hit (which is not really historically correct). In any case if you hit amidships you can always reload and finish them off later. Thanks to the dumb AI the liners and auxiliary cruisers are likely to start zigzagging and may slow down slightly after the first torpedo hits, but they will not use their full speed or change base course. Just shoot them one by one as they go past.
With the type II boat it's usual that I cripple a ship then have to sit there with no torpedoes left. I've waited DAYS in game for ships to sink and a few times have had to wait for the weather to clear so I could use up the flak ammo (to precious little effect). I understand some people like to ram, but I think that's pushing the game a little too far!
No doubt somebody will now chip in with a story about sinking a cruiser or a battleship with the flak gun.