Whose torpedoes were best?
The Japanese torpedoes were probably the best. That was certainly true at the beginning of the war. The Germans may have been the most creative. The British torpedoes were very reliable. Our torpedoes were the worst, at least until the three most serious problems were fixed. That wasn’t accomplished until late 1943.
The Japanese torpedoes were clearly the most effective at the beginning of the war. The Type 93, now known as the Long Lance, was a famous torpedo that was actually a surface-fired weapon, from destroyers and cruisers. It was used most effectively in the various actions in The Slot or Iron Bottom Sound during the battles for the Solomon Islands (such as Guadalcanal). Their submarines fired the Type 95, which was very similar and just as effective. The submarine version had a warhead of almost 900 pounds. It used oxygen or hydrogen peroxide instead of air for combustion, and that gave them much greater range and less of a wake.
The single most effective spread of the war was fired by CDR Kinashi Takaichi in command of the IJN submarine I-19. Our intelligence did not believe that the damage he had wrought could have been done by one submarine. Only after the war, when JANAC compared records of all attacks and losses, did we realize that one spread had done all that damage.
CDR Kinashi had fired a spread of six Type 95 torpedoes at the carrier Wasp from about 1,000 yards. The Wasp was very vulnerable since she was refueling and rearming her aircraft. Three of the Type 95s with their large warheads set the Wasp ablaze and quickly sank it. Unknown to the Wasp or to CDR Kinashi, one of the misses continued about 12 miles until it ran into the battleship USS North Carolina. The damage put the battleship out of service for a few months until it could be repaired. Another miss found the destroyer USS O’Brien in that same area and damaged it badly. The O’Brien did not sink immediately. However, while she was being towed to San Francisco for repairs, she broke up and sank. All of this from a single salvo of torpedoes.
Another note about Japanese torpedoes. When any torpedo was fired it generally descended about 30 feet in depth until it got up to speed and came back up to the desired depth. Torpedoes dropped from aircraft run even deeper initially. During the attack on Pearl Harbor in 1941, this was an issue for their Type 91 airborne torpedoes. If they had descended that far in the harbor during the attacks, they would have been stuck in the mud. However, the Japanese designed breakaway fins on their torpedoes to keep them from going that deep.
German torpedoes were perhaps the most creative. They developed an electric version that we were eventually able to reverse engineer as our Mark 18. Germany also developed a torpedo that would run straight for a while and then started on a curved path. The idea was that if it hadn’t hit the immediate target, it would wander through a convoy hoping it would eventually find something else. They also developed a homing torpedo before anyone else for use against our escorts and cargo ships.
British torpedoes were not fancy, but they were reliable. They were diesel powered and ran straight and true. Curiously, when the British submarine HMS Conqueror sank the Argentine cruiser ARA General Belgrano during the Falklands War in the early ‘80s, the captain chose the WW2 Mark 8 torpedoes. The British were having problems with their brand-new Mark 24 Tigerfish torpedoes, and the skipper decided to go with the reliable Mark 8s. This was somewhat fitting since the General Belgrano was originally the WW2 American cruiser USS Phoenix.