Ships that break in half
A destroyer taking a torpedo used to do the same thing a destroyer taking anything else did: slide under on an even keel. That's not how ships die. Now a torpedoed hull folds in half at the hit — and the way she goes down tells you what killed her.
The jackknife
Put a fish into a destroyer and the hull splits at midships. The bow half rears up out of the water — nav lights pointing at the sky — while the stern folds down and goes under first; the two halves pull apart at the break, secondary explosions rip down the deck over the first few seconds, and a gout of white steam boils up where the break meets the water. It plays out over about ten seconds, so a torpedo kill is a spectacle, not a status change. A ship killed by gunfire still settles and lists the old way — which means you can read the weapon off the death from across the map.
The death tells you the weapon
Watch a fleet go under and you know what killed it before the splash settles. A hull that jackknifes and breaks its back took a fish. A hull that settles low and rolls onto its beam ends was pounded under by gunfire. From the far side of the map, the way a ship dies is now the after-action report — who's carrying torpedoes, and who's trading broadsides.
For now it's the anchored fleet that folds this way; the ships you crew yourself still settle when they go. Paired with the oil slick a sinking leaves spreading across the water, a torpedo run finally looks like what it is: the most violent thing that happens on the Brick Sea.