Torpedo Run could hurt Oi slightly over cost though she already is) Torpedo Run would also pair well with Torpedo Survivor, since Shiranui will likely be in the middle of fighting (and within range of enemy Torps). Cruiser Slayer might be rather too powerful with Torpedo Run.
To take up Scheerluck's suggestion: Oyashio also torpedoed a cruiser and tried to torpedo USS Washington, which could give the ability Valiant Stand
A version of Night Fighter that affected torpedoes could also be interesting and a novel alternative.
Night Barfighter: Once per game, if it's turn 4 or later, this unit may reroll one Torpedo attack.
University Student— Lover of Plato, Aristotle, War At Sea, Palestrina, and Mozart
Another interesting name alternative for a potential night fighter torp ability could be Night Brawl(er) or similar. Thinking about the 'bar room brawl' tag some of these close in night battles were given as well.
Otherwise valiant stand could be an option.
"That's right son, join the navy. Get behind a bloody big gun and knock the hell out of somebody"
"We went out, got our arses kicked, then came back again"