Human torpedo attack at Ulithi

Throughout the month of November in 1944, my dad's repair ship, USS Hector, continued its extensive repair work on USS Houston for combat damage received earlier in October. So far the work had been hampered by bad weather, the most serious of which was a typhoon that hit the area from November 6th to the 8th.

Back on the repair job early on today's date in 1944, Hector's crew heard a huge explosion and saw fire and billowing black smoke from another ship anchored in the lagoon. It was the fleet oiler, USS Mississinewa, just attacked by a human torpedo, a Japanese suicide mini-submarine called a "Kaiten."

Earlier that morning 2 enemy tender submarines near Ulithi, I-36 an I-47, launched 4 mini-subs toward the anchored fleet.* After the attack on the Mississinewa, U.S. destroyers began dropping depth charges throughout the anchorage. The Case rammed 1 in the early morning hours. At 6:25 the cruiser Mobile reported that a torpedo had passed under its bow. The destroyer escorts Rall, Halloran, and Weaver attacked and sank a mini-sub.

Source: Naval History and Heritage Command

The Hector's Log reported that it was in "Condition One" from the time of the attack until after 2 PM. The crew manned its guns, and boats were launched to patrol the water around the vessels. No contact was made, but sailors witnessed 2 underwater explosions in the atoll, which indicated the presence of additional torpedoes.

The sinking Mississinewa, November 20, 1944
She was the first ever victim of a Japanese human torpedo attack.
Source: National Archives

The explosion on the Mississinewa had ignited thousands of gallons of diesel and aviation fuel. Flames spread forward to the magazine, which caused a heavier explosion than the first. Nearby ships sent boats to rescue many of the men who escaped into the flaming waters, but after burning for several hours, the ship rolled over and sank to the bottom of the lagoon, taking 60 crewmen with her to her grave.

Kaiten Type 1
Source: Wikimedia Commons

* The Kaiten Type 1, was essentially a modified, 48-foot long torpedo, loaded with explosives, and controlled by a single man sealed inside. Once ensconced within, the pilot could not unlock the hatches. It was a 1-way mission.

Five of these suicide torpedoes were launched on Ulithi that morning from 2 subs lurking outside the lagoon. The I-47 launched her Kaitens, but none was successful in hitting a target. Three of the manned torpedoes on I-36 were unable to launch due to mechanical problems, but the remaining one successfully struck the Mississinewa with catastrophic results. This won't be the last time that the I-36 will launch a similar attack on Ulithi.

Sources: USS Hector AR7- Ship’s Log (WWII); USS Hector War Diary Nov 1944; Pacific Wrecks