© 2011 Bob Hackett

The Final Destruction of Japan’s Submarine Fleet

(I-402 colorized photo by Irootoko Jr)

By Bob Hackett and Derek Waller

On 26 July 1945, the United States, United Kingdom and the Republic of China announced their proposed terms for Japan's surrender, which included the statement that: "The Japanese military forces shall be completely disarmed".

On 21 September 1945, after the Japanese surrender, and to implement this policy, the US Government issued a document entitled “US Initial Post-Surrender Policy for Japan” which included statements that: “Japan’s ground, air and naval forces shall be disarmed and disbanded” and “Naval vessels shall be surrendered and shall be disposed of as required by the Supreme Commander” (General of the Army Douglas MacArthur). As a result, all surrendered Japanese submarines were to be demolished, scuttled, or otherwise destroyed.

At the end of the war, 49 former Imperial Japanese Navy (IJN) submarines surrendered afloat in the Far East. The majority of these boats, including three ex-U-Boats (U-511 in Maizuru and UIT-24 and UIT-25 at Kobe, surrendered to US forces in Japan. The total also included four other ex-U-Boats that had surrendered to the Royal Navy in Singapore (2) and Java (2). All four of these ex-U-Boats were sunk/scuttled in February 1946 in accordance with the recommendations of the Tripartite Naval Commission (TNC) set up following the Potsdam Declaration in Europe to dispose of the remnants of the Nazi fleet.

The 49 IJN submarines that surrendered afloat were:
I-14, I-36, I-47, I-53, I-58, I-121, I-155, I-156, I-157, I-158, I-159, I-162, I-201, I-202, I-203, I-363, I-366, I-367, I-369, I-400, I-401, I-402, I-501 (U-181), I-502 (U-862), I-503 (UIT-24), I-504 (UIT-25), I-505 (U-219) and I-506 (U-195)
RO-50, RO-62, RO-63, RO-68 and RO-500 (U-511)
HA-103, HA-105, HA-106, HA-107, HA-108, HA-109, HA-111, HA-201, HA-202, HA-203, HA-204, HA-205, HA-207, HA-208, HA-209 and HA-210

In October 1945, five IJN ‘super” submarines (I-14, 1-201, I-203, I-400 and I-401) were moved from Japan to Pearl Harbor, Hawaii for test and evaluation by the USN. These were to be destroyed at the discretion of the C-in-C Pacific Fleet.

A number IJN submarines were surrendered at the IJN base at Sasebo, near Nagasaki, in the far west of Kyushu. In late 1945, most other IJN submarines were moved from the ports where they had surrendered to Sasebo, especially those from Kure.

On 26 March 1946, at a Submarine Officers’ Conference in Washington DC, it was decided that all remaining captured Japanese submarines (including those which had been captured incomplete or which has already been decommissioned at the time of their capture) were to be sunk by the US Navy, including the five at Pearl Harbor. [1]

This decision included the three ex-U-Boats that had surrendered in Japan, but had not been destroyed in accordance with the TNC’s recommendations because the US Navy’s CNO successfully argued that they were Japanese submarines when they surrendered and therefore outside the TNC’s jurisdiction.

There were five main disposal areas for the Japanese submarines that were to be sunk at sea. These were Maizuru Bay, Kii Suido, Iyo Nada (The Inland Sea), off Sasebo Bay, and at “Point Deep Six” off the island of Goto-Retto about 40 miles west of Nagasaki.

(Final Sortie from Sasebo)

On 1 April 1946, the main disposal event, Operation “Road’s End”, took place. Twenty-four IJN submarines capable of sailing under their own power and manned by skeleton Japanese crews left Sasebo and were assembled at “Point Deep Six”. There, they were sunk near the 100 fathom line, either by demolition charges or by gunfire from the US Navy’s submarine tender USS NEREUS (AS-17) and destroyer EVERETT F. LARSON (DD-830).

The 24 IJN submarines sunk off Sasebo in Operation “Road’s End” on 1 Apr 1946 were: I-36, I-47, I-53, I-58, I-156, I-157, I-158, I-159, I-162, I-366, I-367, I-402, RO-50, HA-103, HA-105, HA-106, HA-107, HA-108, HA-109, HA-111, HA-201, HA-202, HA-203 and HA-208. [2]

("Roads End" subs underway)

Off Sasebo Bay. On 5 April 1946, in the next action, Operation “Dead Duck”, four disabled former IJN submarines were towed to sea and sunk by explosive charges. These were I-202, HA-207, HA-210 and HA-216.

On 16 April 1946, I-503 (former Italian COMANDANTE ALFREDO CAPPELLINI, later German UIT-24) was sunk by the USN in the Kii Suido (Strait) between the islands of Honshu and Shikolu. She had been captured in the Mitsubishi Shipyard at Kobe, on the south coast of Honshu.

That same day, I-504 (former Italian LUIGI TORELLI, later German UIT-25 was also sunk by the USN in the Kii Suido. She had been captured in Kawasaki’s Shipyard at Kobe.

On 30 April 1946, RO-500 (ex-German U-511 was sunk by the USN in the Sea of Japan in Wakasa Bay near Maizuru on the north coast of Honshu Island where she had been surrendered.

The exact circumstances of the three ex-U-boats final disposal are unclear, although it seems probable that they may have been towed to sea and scuttled with internal demolition charges.

IJN submarines I-121 and RO-68 were also scuttled off Maizuru on 30 April 1946.

Beginning in May 1946, the last operations were conducted by the USN to destroy the five IJN submarines that had undergone test and evaluation at Pearl Harbor. All were sunk off Hawaii by United States submarines:

I-203 was sunk on 21 May 46 by USS CAIMAN (SS-323), I-201 on 23 May by USS USS QUEENFISH (SS-393), I-14 on 28 May USS BUGARA (SS-331), I-401 on 31 May by USS CABEZON ((SS-334), and finally I-400 sunk on 4 Jun 46 by USS TRUMPETFISH (SS-425). [3]

It has been possible to detail where and when the 49 former IJN submarines shown above met their final end; but details are less precise concerning the 100 or so other (unseaworthy) submarines captured in Japan at the end of the war. Further, the Imperial Japanese Army (IJA) had operated a number of transport submarines and seven of these were surrendered at the end of the war.

On 3 February 1946, I-505 (ex-U-219) was sunk south of Sunda Strait, Indonesia by Royal Netherlands Navy destroyer Hr.Ms. KORTENAER (ex-British HMS SCORPION). Then on 15 February 1946, three more ex-U-boats, I-501 (ex-U-181) and I-502 (ex-U-862) were sunk by Royal Navy frigates HMS LOCH LOMOND and HMS LOCH GLENDHU in the Straits of Malacca, off Singapore, while I-506 (ex-U-195) was sunk the Royal Navy’s cruiser HMS SUSSEX in the Bali Sea, east of Kangean Island.

Only a few former IJN submarines were left afloat and these were scuttled in the Iyo Nada (Inland Sea) in May 1946. They were I-155, RO-62, RO-63 and HA-205.

In 1946, two submarines were scrapped in their yards in 1946. They were I-369 at Yokosuka Navy Yard and HA-209 at Mitsubishi's Shipyard at Shimonoseki. HA-204, that had grounded in Aburatsu Bay in October 1945, was the last submarine to go. Her hulk was scrapped in 1948.

General MacArthur’s Report records that, by October 1946, all submarines (a total of 151) had been disposed of. The Report quotes a June 1949 in the Tokyo “Pacific Stars and Stripes” newspaper article dated that when the IJN disposal task was complete, “42 submarines had been scrapped and a further 104 had been sunk”.

Authors' Notes:
[1] Reportedly, I-400, I-401, I-14 and the I-200 class submarines were sunk to prevent their technology from being surrendered to the Russians.

[2] In 2004, co-author Bob Hackett worked with Parallax Film productions of Canada which produced "Sen Toku: The Search for Japan's Ghost Fleet" that aired as a Discovery Channel special that year. This search located several of the 24 former IJN submarines scuttled off Goto Retto in "Operation Road's End".

[3] On 17 March 2005, off Oahu, Hawaii, the Hawaii Undersea Research Laboratory's (HURL) deep-diving submersibles Pisces IV and V located I-401 off the coast of Kalaeloa. I-401 lies in about 870 meters (2827 feet) off the coast of Barbers Point.

[4] On 15 February 2009, off Barber's Point, Hawaii, HURL’s deep-diving submersibles Pisces IV and Pisces V located I-14 ; The wreck’s portions lies at a depth of about 800 meters. The next day, Pisces IV located I-201 nearby.

Co-author Derek Waller, Air Commodore, RAF (Ret), authored many fine articles concerning the post war surrender and destruction of German U-boats that are posted on the excellent uboat.net website.

Thanks go to Sander Kingsepp of Estonia for providing some Japanese language source data.

-Bob Hackett and Derek Waller

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