IJN
Sentoku Type
I-400 Class Submarine
August 27, 1945
Length
400' (122m)
Tons
3,530 (surfaced)
5,223 (submerged)
Range
37,500 nautical miles
Armament
8 x torpedo tubes
5.5" deck gun
bridge 25mm AA gun
3 x 3x25mm AA gun
Hanger
3 x Seiran Float
Planes
Crew
21 officers
174 enlisted men
Captain Tosho Kusaka
Ship History
Construction began on January 18, 1943 at Kure Dock Yards under heavy security. Completed on December 30, 1944. It included radar and radar detectors. The main feature of the sub was its watertight hanger for three Serian seaplanes.
Wartime History
It was planned to use the I-400 along with the I-401, I-13 and I-14 to participate in a daring plan to attack the Panama Canal and disable its locks. In June 1945 the decision was made to switch targets to hit USN anchorage at Ulithi Atoll. The plan was code-named Arashi (storm) for the I-400 and I-401 to use its Serians on Kamikaze attacks on any carriers based there. The two subs departed Ominato on July 23, 1945. At sea, the sub suffered an electrical fire on August 5th that forced it to surface to repair the damage, but successfully reached their rendezvous point, 100 miles miles south of Ulithi on August 14th, but the I-401 was not there. The strike date was set for August 17th, but Japan surrendered on the 15th.
Surrender
After hearing of the surrender, the Captain elected to return to Kure, to surrender in Japanese home waters. They jettisoned their Serain aircraft. Spotted on August 27th off northern Honshu by Avengers from the USS Bennington. Destroyers USS Blue DD-744 and Mansfield DD-728 pursued the sub and boarded it to accept its surrender. The following day, the USS Weaver DE-741 arrived to again accept its surrender. After surrender, the sub was sailed to Hawaii, and evaluated
by the US Navy.
Sinking History
Sunk by USS Trumpetfish SS-425 on June 4, 1946 during a tests of the Mark 10-3 exploder. After being hit by three Mark 18-2 electric torpedoes, the sub sank in deep water at 12:10, sinking by the stern. Over the course of several days four captured subs were sunk: I-201, I-14, and I-401.
References
The definitive account of the I-400's history, crew, mission, capture, evaluation and sinking is told in the book I-400: Japan's Secret Aircraft-Carrying Strike Submarine: Objective Panama Canal. Air & Space Magazine "All and Nothing" covers the Seiran and I-400 November 2001 Issue, pages 22 - 31.
21 13 N
158 07 W
Google Earth
Tabular Movements
