 One of the few known photos ofU-1224: Japanese officers on itsconning tower at the hand-over ceremony to the Imperial Japanese Navy | |
| History | |
|---|---|
 Nazi Germany | |
| Name | U-1224 |
| Ordered | 25 August 1941 |
| Builder | Deutsche Werft,Hamburg |
| Yard number | 387 |
| Laid down | 30 November 1942 |
| Launched | 7 July 1943 |
| Commissioned | 20 October 1943 |
| Decommissioned | 15 February 1944 |
| Fate | Transferred to Japanese service |
 Empire of Japan | |
| Name | Ro-501 |
| Acquired | 15 February 1944 |
| In service | 15 February 1944 |
| Fate | Sunk on 13 May 1944 |
| Notes | Used as a training ship |
| General characteristics | |
| Class and type | Type IXC/40submarine |
| Displacement | |
| Length |
|
| Beam |
|
| Height | 9.60 m (31 ft 6 in) |
| Draught | 4.67 m (15 ft 4 in) |
| Installed power |
|
| Propulsion |
|
| Speed |
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| Range |
|
| Test depth | 230 m (750 ft) |
| Complement | 4 officers, 44 enlisted |
| Armament |
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| Service record (Kriegsmarine)[1] | |
| Part of: |
|
| Identification codes: | M 53 122 |
| Commanders: |
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| Operations: | None |
| Victories: | None |
| Service record (IJN)[2] | |
| Part of: |
|
| Commanders: |
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| Operations: | Marco Polo II |
| Victories: | None |
German submarineU-1224 was aType IXC/40U-boat ofNazi Germany'sKriegsmarine built for service duringWorld War II. She was constructed byDeutsche Werft ofHamburg, and was commissioned on 20 October 1943, withKapitänleutnant Georg Preuss in command. She was assigned to the31st U-boat Flotilla, a submarine training unit.
In late 1943 and early 1944, she was used as a training ship for Japanese sailors. In the summer of 1943 a full crew of Japanese submariners arrived in Germany to be trained on the operations of German U-boats, on the initiative of the German naval attaché in Japan,Paul Wenneker, who wanted to share German submarine knowledge and technology with the Japanese.U-1224 was transferred into Japanese service on 15 February 1944, after the Japanese crew spent several months training in the Baltic Sea. While inKiel, she was commissioned in theImperial Japanese Navy asRo-501, and shortly afterwards departed for Japan, along with a cargo of war materials and four Japanese naval engineers who had been studying in Germany.
Ro-501 was sunk on 13 May 1944 on her way to Japan by aU.S. Navy anti-submarinehunter-killer group, about 500 nautical miles offCape Verde in the Atlantic, after spending two days trying to evade the pursuers.
German Type IXC/40 submarines were slightly larger than the originalType IXCs.U-1224 had a displacement of 1,144 tonnes (1,126 long tons) when at the surface and 1,257 tonnes (1,237 long tons) while submerged.[3] The U-boat had a total length of 76.76 m (251 ft 10 in), apressure hull length of 58.75 m (192 ft 9 in), abeam of 6.86 m (22 ft 6 in), a height of 9.60 m (31 ft 6 in), and adraught of 4.67 m (15 ft 4 in). The submarine was powered by twoMAN M 9 V 40/46supercharged four-stroke, nine-cylinderdiesel engines producing a total of 4,400 metric horsepower (3,240 kW; 4,340 shp) for use while surfaced, twoSiemens-Schuckert 2 GU 345/34double-acting electric motors producing a total of 1,000 shaft horsepower (1,010 PS; 750 kW) for use while submerged. She had two shafts and two 1.92 m (6 ft)propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).[3]
The submarine had a maximum surface speed of 18.3 knots (33.9 km/h; 21.1 mph) and a maximum submerged speed of 7.3 knots (13.5 km/h; 8.4 mph).[3] When submerged, the boat could operate for 63 nautical miles (117 km; 72 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 13,850 nautical miles (25,650 km; 15,940 mi) at 10 knots (19 km/h; 12 mph).U-1224 was fitted with six 53.3 cm (21 in)torpedo tubes (four fitted at the bow and two at the stern), 22torpedoes, one10.5 cm (4.13 in) SK C/32 naval gun, 180 rounds, and a3.7 cm (1.5 in) Flak M42 as well as two twin2 cm (0.79 in) C/30 anti-aircraft guns. The boat had acomplement of forty-eight.[3]
U-1224/Ro-501 was mounted with a single3.7 cm Flakzwilling M43U gun on the LM 42U mount. The LM 42U mount was the most common mount used with the 3.7 cm Flak M42U. The 3.7 cm Flak M42U was the marine version of the 3.7 cm Flak used by theKriegsmarine onType VII andType IX U-boats.[3]
The submarine's keel waslaid down on 30 November 1942 byBlohm & Voss of Hamburg. She wascommissioned on 20 October 1943, withKapitänleutnant Georg Preuss as its commanding officer.U-1224 was assigned to the31st U-boat Flotilla for training purposes,[4] and was selected to be used as a training ship for Japanese sailors before she was even commissioned.[5]
U-1224 became part of thetransfer of technology and knowledge missions that existed between Japan and Germany duringWorld War II. A full crew of Japanese personnel was to be trained by the Germans to operate a U-boat, after which the boat would be gifted to Japan. This training mission was arranged by the German naval attaché in Tokyo,VizeadmiralPaul Wenneker, who wanted to share German submarine technology and tactics with the Japanese. He advocated for giving German submarines to Japan and to train Japanese submariners in Germany.[6] In August 1943, Lieutenant Commander Sadatoshi Norita and a 48-man Japanese crew arrived inFrance aboardsubmarineI-8, and proceeded to Germany by train, where they began working with a small crew ofKriegsmarine sailors in the Baltic from October 1943 until February 1944 in German submarine handling.[1][4]
U-1224 was to become the second submarine to be transferred to Japan by the Germans, afterAdolf Hitler made the decision in February 1943 to send twoKriegsmarine U-boats to Japan as part of a campaign against Alliedsea lines of communication in the Indian Ocean.[7] The head of the navy,GroßadmiralKarl Dönitz, was against giving German submarines to the Japanese as he believed that Germany needed all of its U-boats in the Atlantic, and thought that Japanese and German crews would not get along well, but he was overruled by Hitler.[5][7] The first,U-511, was code-named "Marco Polo I" and departed Germany in May 1943, carrying along with its German crew several passengers that included engineering officers, the Japanese naval attachéNaokuni Nomura, and the diplomatErnst Woermann, who was going to take up his post as German ambassador to the pro-Japanese collaborationistWang Jingwei regime inChina. She also had some supplies for the Indian Ocean-based GermanMonsun Gruppe.U-511 successfully arrived inPenang,Japanese-occupied Malaysia, in July 1943, where the supplies were offloaded, and then arrived inKure, Japan, in August 1943. She was then commissioned into the Imperial Japanese Navy asRo-500.[7] ThereforeU-1224 was code-named "Marco Polo II" by the Germans.[4]
After the crew underwent three months of training,U-1224 was recommissioned into theImperial Japanese Navy asRo-501, on 15 February 1944. Lieutenant Commander Sadatoshi Norita was formally appointed her commanding officer, andRo-501 was nicknamed "Satsuki No. 2" by its new Japanese crew, who then spent several weeks from late February to late March 1944 doing further training at the U-boat anti-aircraft school inSwinemunde.[4]Ro-501 was to be assigned to the8th Submarine Squadron, which was based in Malaysia.[2]
Germany and Japan were separated by great distance, and by 1944 they were increasingly cut off from each other. While neither power was able to send meaningful reinforcements or armaments through territory controlled by the Allied powers, they were able to use submarines to share some intelligence and weapons blueprints. Submarines offered security and their stealth allowed for a fair chance of success. At the end of March 1944, several Japanese naval engineering officers that had been studying in Germany, led by Captain Tetsuhiro Emi, arrived inKiel, where they boardedRo-501 and departed for Japan along with some war materials. They also took with them mercury, lead, steel, uncut optical glass and aluminum, along with the blueprints to construct aType IX submarine and a MesserschmittMe 163 "Komet" jet fighter.[4][6]
U-1224 arrived inNorway on 30 March 1944 to refuel, and continued on its journey in early April, initially along with the German submarineU-859, which was also carrying a cargo of war material bound for Japan.[4]
The intended route to Penang was to takeRo-501 through the middle of the Atlantic Ocean west of theAzores and theCape Verde Islands, then around theCape of Good Hope. She was to rendezvous withI-8 in theIndian Ocean to refuel before proceeding to her destination.[4] However, at30°0′0″N37°0′0″W / 30.00000°N 37.00000°W /30.00000; -37.00000,Ro-501 ran into aU.S. Navyhunter-killer group comprisingescort carrierUSS Bogue and fivedestroyer escorts, includingUSS Francis M. Robinson. The group's presence forcedRo-501 underwater for two days, during which her batteries were depleted and her captain, Lt. Cmdr. Norita, radioed a coded signal that he was being pursued. This transmission was detected by the American ships with theirhigh-frequency direction finding ("Huff-Duff") equipment, enabling them to pinpoint the submarine's location.[4]
TheFrancis M. Robinson reported a submerged contact at 19:00 on 13 May 1944. The destroyer escort engaged the contact with a full salvo from its forward-throwingHedgehog mount, followed by five salvos ofmagnetic proximity fuzeddepth charges.[8] Four underwater explosions were detected.[4] In early July 1944, the German naval attaché in Japan, Paul Wenneker, sent a message to Berlin asking about the status ofRo-501, to which he received the answer that U-boat Command had not heard from the submarine since 11 May. On 26 August 1944, she was presumed to be lost by the German Navy with all 56 hands aboard – 52 Japanese crew (including a German radar operator and a German pilot) plus four Japanese officer passengers. She was struck from the navy list on 10 October 1944.[4][6] Her commanding officer, Norita, received a posthumous promotion to the rank ofcommander from the Imperial Japanese Navy, as did one of the passengers, Tetsuhiro Emi, torear admiral.[4][9]
The final resting place ofU-1224/Ro-501 is 500 nautical miles (930 km; 580 mi) west-northwest of the Cape Verde islands at18°7′59″N33°12′59″W / 18.13306°N 33.21639°W /18.13306; -33.21639 in 2,900 feet (880 m) of water. This is a few miles from whereUSS Buckley sankU-66.[8][10]
Shipwrecks and maritime incidents in May 1944 | |
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| Shipwrecks |
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| Other incidents |
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