In World War II, the Mark XIV torpedo was the bane of the U.S. Pacific naval fleet. And it was an American torpedo.
(Bear with me; I have a point.)
This torpedo had a high dud-rate, or rate of non-exploding explosives. The most significant example I know of happened in July 1943. The American submarine Tinosa had spotted a Japanese oil tanker, and having lined her up perfectly, fired a salvo of four Mark XIV torpedoes. Through the periscope, the crew observed two direct hits by the telltale splashes on the tanker's hull, but there was no explosion. At that point the tanker sped up and turned to flee, realizing that she was under attack. Tinosa fired two more torpedoes at the tanker's stern and they made contact and hit, successfully exploding. This crippled the massive tanker but did not sink her, so the Tinosa maneuvered to a new angle of attack and fired a single torpedo at the enemy ship. Again, however, the torpedo was a dud and produced only a splash on the tanker's side.
Seven more torpedoes were fired with the same lack of effect.
Cutting his losses, the skipper of the Tinosa, Lt. Cmdr L. R. Dapsit, ordered his ship back to port, saving his last torpedo for a thorough inspection. He used his tale to begin a lengthy process to convince his superiors that the Mark XIV torpedo was unreliable, and the full tale of the red tape involved can be found here.
The reason I'm referring to this historical anecdote is to announce that my own self-inflicted torpedo, as referenced a few days back, was a dud - and I got the promotion I was so eagerly hoping for.
I hope I didn't bore you before you got to the announcement. :)