© 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
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
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
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. 
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. 
("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
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
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
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
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”.
 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.
 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".
 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.
 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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