ORIGINAL: Lokasenna
The SSX torpedoes don't do a lot of damage. I think "critical damage" is more of a multiplier on the damage done (which starts lower for the 45cm midget torps) than damage relative to the ship itself.
The SSX torpedo device has an effect of 772. The regular IJN submarine torpedoes, 53cm, have an effect of either 893 (type 95) or 661 (type 89, some of the early-war smaller submarines). That you didn't see "heavy damage" on Alabama despite 2 critical damage torpedo hits speaks to this difference in effect, I think.
That's encouraging!















