IJN Submarine RO-500 (Ex-U-511):
Tabular Record of Movement

(RO-500 (ex-U-511)

© 2001-2018 Bob Hackett & Sander Kingsepp
Revision 8

21 February 1941:
Hamburg, Germany. A 1,120-ton (surfaced) type IXC U-boat, is laid down at Deutsche Werft AG.

22 September 1941:
Launched and numbered U-511.

8 December 1941:
Completed and commissioned in the Kriegsmarine. Kapitänleutnant Friedrich Steinhoff is the Commanding Officer.

31 May-5 June 1942:
Peenemünde, Germany. Steinhoff and his brother Dr. Ernst Steinhoff, an engineer at the Peenemünde rocket development facility, discuss the feasibility of firing an artillery rocket from the deck of a submerged submarine. During the summer, U-511 is used for rocket tests on the Baltic coast of Germany. A rack for six 30-cm Wurfkörper 42 Sprengraketen rockets is installed. Tests are carried out, including a successful launch of the rockets from a depth of 12 meters.

Vizeadmiral Karl Dönitz, Befehlshaber der Unterseeboote (BdU) (CINC, U-boats), approves the concept of launching the rockets against New York City, but the plan is delayed for technical reasons and is eventually cancelled.

August 1942-July 1943:
U-511 sinks five ships for a total of 41, 373 tons and damages an 8,773-ton tanker. [1]

18 December 1942:
Kapitänleutnant Fritz Schneewind assumes command. Steinhoff later becomes the CO of U-873.

26 February 1943:
Vinnitsa, Ukraine. During a conference with Dönitz in Führer’s HQ, Hitler makes the final decision about the transfer of two Kriegsmarine U-boats to Japan in order to launch a full-scale campaign against Allied communications in the Indian Ocean. Dönitz opposes the idea, but is quickly overruled.

3 March 1943:
Vice Admiral Nomura Naokuni (35)(former CO of KAGA), Japan's representative to the Axis Tripartite Commission in Berlin since 1941, is ordered to return to Japan on the next outgoing submarine. Japanese naval attaché Rear Admiral Yokoi Tadao (former CO of CHIYODA) also authorizes the departure of Maj Sugita Tamotsu of the IJA Medical Service, who had been studying in Germany.

Late April 1943:
Vice Admiral Nomura and Maj Sugita are invited to a farewell party in Hitler’s Berlin residence. During that party Field Marshal Wilhelm Keitel, Chief of the German Wehrmacht, personally authorizes export of Daimler-Benz MB-518 diesel engines for use on Japanese torpedo boats. The first example is sent to Lorient, France, for embarkation on U-511.

10 May 1943:
Lorient, France. Early in the morning, Vice Admiral Nomura and Maj Sugita arrive by train from Berlin. After 1300, U-511 ("Marco Polo 1") departs for Penang, Malaya. U-511 also carries a full set of Messerschmitt Me-163 "Komet” rocket interceptor blueprints, samples of yellow fever vaccine, spare torpedoes and supplies for the German U-boat "Gruppe Monsun" (Monsoon) being organized at Penang. [2]

U-511 carries a crew of 49 and nine passengers - five Germans and four Japanese. Among the Japanese are Vice Admiral Nomura and Major Sugita. The Germans include Dr. Ernst Wörmann, ambassador to Wang Jing-we's pro-Japanese collaborationist government at Nanking, China and Franz-Joseph Spahn, en route to Japan as an "overseer" for the Jewish refugee policy in Manila and three engineers from U-boat builder Deschimag AG Weser at Bremen: Mssrs. Herberlein, an auxiliary engine specialist Hans Schmidt, a welding technician, and Müller of the Type IXC construction office.

During transit, U-511 is designated by the Japanese as "Satsuki (Month of First Buds) No. 1."

22 May 1943:
W of Freetown, Liberia, Africa. U-511 makes a planned rendezvous with Kapitänleutnant Ebe Schnoor's U-460, a Type XIV "Milchkuh" (Milk Cow) tanker. U-511 takes on fuel and provisions. After refueling U-511, U-460 departs for France arriving on 25 June. U-511 heads for the Indian Ocean.

27 May 1943:
U-511, travelling at an average submerged speed of 3 knots, crosses the equator.

10 June 1943:
U-511 enters the Indian Ocean.

27 June 1943:
Indian Ocean. U-511 torpedoes 7,194-ton American "Liberty" ship SEBASTIAN CERMENO en route from Mombasa, Kenya to Bahia, Brazil. She sinks at 28-50S, 50-20E. Schneewind surfaces to question survivors, then submerges and retires from the area.

9 July 1943:
Indian Ocean. U-511 torpedoes 7,176-ton American Liberty ship SAMUEL HEINTZELMAN en route from Fremantle, Australia via Colombo, Ceylon to Calcutta, India, loaded with 5,644-tons of ammunition. When the torpedoes hit the ship, she disintegrates in a massive explosion! The entire crew of 75 perishes. She sinks at 09-00S, 81-00E.

15 July 1943:
Andaman Sea. At the appointed time, U-511 makes a rendezvous with minelayer HATSUTAKA attached to the First Southern Expeditionary Fleet. Vice Admiral Nomura and Major Sugita briefly visit HATSUTAKA for a bath and then return to the U-boat.

16 July 1943:
Penang, Malaya. U-511 is the first German U-boat to arrive at the base. It subsequently becomes home for the "Monsun" Group. Admiral Nomura disembarks and he and the other Japanese continue on to Japan by air. Schneewind embarks a group of IJN officers including Lt Honda Yoshikuni (former navigating officer of I-17 and future CO of RO-41). [3]

24 July 1943:
At 1600, U-511 departs Penang for Kure. [4]

29 July 1943:
At 1650, the surfaced U-511 encounters Singapore-bound convoy HI-03 consisting of ARIMASAN, ASAMA, AWA and NANKAI MARUs and tanker OMUROSAN MARU. The convoy is escorted by kaibokan ETOROFU. The sighting of a strange-looking submarine causes confusion aboard OMUROSAN MARU and her gunners fire three shells at U-511, before the mistake is cleared up. The skipper of ETOROFU inspects U-511 and personally apologizes for the attack. [5]

5 August 1943:
Off the Bungo Suido (Strait). At 0800 U-55 rendezvouses with minelayer NUWAJIMA appointed to escort her for the remainder of voyage. Soon thereafter, a Japanese patrol aircraft reports the sighting of a submarine en route of U-511. NUWAJIMA conducts a depth-charge attack, while Schneewind continues the voyage independently. U-511 and NUWAJIMA stop at Agenosho Bay off Yashiro Jima for the night.

7 August 1943:
Kure. U-511 arrives. Kapitänleutnant Schneewind and his crew are hosted by the CO of the Kure Naval Base, Vice Admiral (Admiral, posthumously) Nagumo Chuichi (36)(former CO of YAMASHIRO). Schneewind and several officers later travel to Tokyo, where they receive decorations from Navy Minister Admiral Shimada Shigetaro (32)(former CO of HIEI) and Chief of the NGS, Fleet Admiral Nagano Osami (28)(former CO of HIRADO).

16 September 1943:
Kure. U-511 is formally handed over, commissioned in the IJN as RO-500 and attached to Kure Naval District. LtCdr Taoka Kiyoshi (55)(former CO of I-54) is the Commanding Officer. [5]

Kure. RO-500 is put through trials and evaluated by a team of IJN engineers led by Constructor Vice Admiral Fukuda Keiji, one of the designers of the YAMATO class battleships. The IJN team is assisted by three German engineers attached to the Naval Technical Institute in Tokyo. After careful study, the engineers point out several shortcomings of the IXC design, such as low underwater speed, unreliable diesel engines, inadequate ventilation and cooling equipment and limited range.

Earlier, a proposition was put forward to launch serial production of Type IXC submarines equipped with Japanese powerplants and weapons (tentatively designated as IXK by the Germans). Vice Admiral Fukuda rejects the proposition and instead recommends that all available resources be devoted to construction of the new I-201-class ("Sen Taka") high underwater speed submarines. Several features of U-511 are used in this design, including the electric welded pressure hull, prefabricated hull section, and re-designed engine mountings to reduce vibration and engine noise.

Late September 1943:
Kure. After teaching handling of the U-boat to the Japanese, U-511's German crew departs aboard the Italian freighter OSORNO bound for Singapore. Later, the crewmen make their way to Penang. [6]

1 November 1943:
RO-500 is attached to the Otake Submarine School for testing and training purposes.

3 December 1943:
LtCdr Taoka is attached to Headquarters, Sixth Fleet. RO-500's torpedo officer Lt Uesugi Sadao (65)(former torpedo officer of I-20) is appointed the acting CO of RO-500.

31 January 1944:
RO-500's torpedo officer Lt Yamazaki Toshio (67) is appointed the acting CO of RO-500.

30 April 1944:
Lt (later LtCdr) Shiizuka Mitsuo (66)(former torpedo officer of I-185) is appointed the CO.

2 May 1944:
Assigned to SubDiv 33 at Kure with RO-62, RO-63 and RO-64. Later that month, RO-500 commences joint exercises with Yokosuka D4Y2 Suisei ("Judy") dive-bombers of the 634th NAG, soon to be embarked on the hybrid carriers of the ISE class. RO-500 acts as the ASW target for the dive-bomber crews.

1 July 1944:
Reassigned to Kure Guard Unit.

5 July 1944:
Lt (later LtCdr) Yamamoto Yoshio (66)(former torpedo officer of I-361) is appointed the CO.

15 August 1944:
RO-500 is in the Kure Naval District with RO-62 and RO-68. Training duties.

15 September 1944:
Lt Yamamoto Yasuhisa (67)(former navigating officer of RO-114) is appointed the CO.

Late September 1944:
The staff of Saeki NAG requests two submarines from the Kure Naval Base HQ to simulate "intruders" for ASW aircraft crews. RO-500 is one of the candidates with RO-68, but cannot participate because of diesel repairs.

5 May 1945:
Reassigned to 51st Escort Squadron at Maizuru to simulate US submarines for subchaser/kaibokan crews.

Kure Navy Yard. I-155 through I-158 are repainted to test the efficiency of the German light grey camouflage scheme. Subsequent trials reveal no advantages over the scheme used on Japanese submarines.

12 August 1945:
Arrives at Maizuru following the Soviet invasion of Manchuria. Embarks fuel and ammunition.

15 August 1945: End of Hostilities with the Allies:
RO-500's crew joins the rebels and decides to continue fighting against the Soviets.

18 August 1945:
Early in the morning departs Maizuru for Sakhalin waters. Sixth Fleet HQ learns about the sortie and addresses the crew of RO-500 by radio. A floatplane manages to locate the submarine and on the evening of 18th she returns to Maizuru.

September 1945:
Maizuru Navy Base. RO-500 is surrendered to Allied Forces.

10 October 1945:
Removed from the Navy List.

13 October 1945:
At Maizuru with I-121, I-201, I-202, RO-18 and RO-68.

30 April 1946:
Off Kanmuri Jima, Wakasa Bay. RO-500 is scuttled by the U.S. Navy.

(I-121, RO-68 and RO-500's final day at Maizuru)

18-21 June 2018:
The Society La Plongée for Deep Sea Technology research team led by Research Professor Ura Tamaki from Kyushu Institute of Technology locates and photographes the wrecks of RO-500, I-121 and RO-68, using a multibeam echosounder and an ROV. The wreck of RO-500 is located at the depth of 290 ft and identified by its distinctive bow shape.

Authors' Notes:
[1] This total of ships sunk includes both ships sunk by U-511 while she was enroute to Japan.

[2] One of three sets of Me-163 blueprints carried to Japan by submarine; the others are later carried aboard I-29 and RO-501. Only the Me-163 blueprints carried on U-511 and I-29 made it to Japan. They were used to develop the Mitsubishi J8MI Shusui ("Sword Stroke").

[3] Nomura later becomes the CINC, Kure Naval Station and, as a full Admiral in 1944, Vice Minister of the Navy. Many authors confuse Admiral Nomura Naokuni (35) with Admiral Nomura Kichisaburo (26).

[4] Axis propaganda asserted U-511 was a "gift" from Hitler to Emperor Hirohito. Actually, the Germans treated U-511 as a partial payment for Japanese supplies (raw rubber and torpedoes in particular) already delivered by surface blockade runners. The Japanese and Germans always dealt on a strictly hard currency (or gold) basis.

[4] According to some German sources, Captain Okuda Masuzo had been appointed CO of U-511 by then. This is incorrect, since Okuda was the highest-ranking passenger aboard the submarine during her voyage to Kure. The first Japanese skipper of U-511/RO-500 was appointed on 16 September 1943.

[5] In some postwar German sources the "friendly fire" accident of 29 July has grown into a major naval battle between the U-511 and the surface units of the IJN. Moreover, they state that the "battle" could only be stopped after Vice Admiral Nomura challenged the attackers by radio. In reality, Nomura had already left the sub at Penang, after he developed heart trouble.

[6] U-511's crew later becomes a spare crew for the U-boats that operate from Penang. They also form the backbone of repair and maintenance capability of that small (five U-boat) base.

On 20 Nov '43, Schneewind is given command of U-183 at Penang. He was KIA 23 April 1945 in the Java Sea when U-183 was torpedoed and sunk by USS BESUGO (SS-321).

Thanks go to Dr. Higuchi Tatsuhiro of Japan. Special thanks for assistance in researching the IJN officers mentioned in this TROM go to Mr. Jean-François Masson of Canada.

-Bob Hackett and Sander Kingsepp.

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