Monsun Gruppe

The Monsun Gruppe or Monsoon Group was a force of German U-boats (submarines) that operated in the Pacific and Indian Oceans during World War II. Although similar naming conventions were used for temporary groupings of submarines in the Atlantic, the longer duration of Indian Ocean patrols caused the name to be permanently associated with the relatively small number of U-boats operating out of Penang, (with its capital, Georgetown) The Indian Ocean was the only place where German and Japanese forces fought in the same theatre. Arrangements were made to avoid incidents between U-boats and Japanese submarines - attacks on other submarines were strictly forbidden.

Indian Ocean trade routes

The Indian Ocean was considered strategically important, containing not only India, Britain's most prized possession, but also the shipping routes and strategic raw materials that the British needed for their war effort. In the early years of the war German merchant raiders and pocket battleships had sunk a number of merchant ships in the Indian Ocean; however as the war progressed it become more difficult for them to operate in the area and by 1942 most were either sunk or dispersed. From 1941, U-boats were also considered for deployment to this area but due to the successful periods known as the First and Second Happy Times, it was decided that sending U-boats to the Indian Ocean would be an unnecessary diversion. There were also no foreign bases in which units could operate from and be resupplied, hence they would be operating at the limits of their range. As a result the Germans concentrated their U-boat campaign in the North Atlantic.

Japan’s entry into the war in 1941 led to the capture of European South-east Asian colonies such as British Malaya and the Dutch East Indies. In May and June, 1942, Japanese submarines began operating in the Indian Ocean and had engaged British forces in Madagascar. The British had invaded the Vichy-controlled island in order to prevent it from falling into Japanese hands.

Axis strategic raw materials

The German invasion of the Soviet Union in 1941 had ended the use of overland routes which were for the delivery of strategic materials from southeast Asia, and few axis ships were able to avoid Royal Navy patrols of the North Atlantic. Japan was interested in exchanging military technology with Germany, the Japanese submarine I-30 initiated the submerged transport of strategic materials in the summer of 1942 by delivering 1500 kg of mica and 660 kg of shellac. Japanese submarines designed for the vast distances of the Pacific were more capable transports than the compact German U-boats which were designed for operations around coastal Europe; but large Italian submarines had proved ineffective for convoy attacks. The Italian Royal Navy (Regia Marina) converted seven Italian submarines operating from BETASOM into "transport submarines" in order to exchange rare or irreplaceable trade goods with Japan. They were: The Bagnolin, the Barbarigo, the Cappellini (renamed Aquilla III in May 1943), the Finzi, the Giuliani, the Tazzoli and the Torelli.

Joint operations in the Indian Ocean

The idea of stationing U-boats in Malaya and the East Indies for operations in the Indian Ocean was first proposed by the Japanese in December 1942. As no supplies were available at either location, the idea was turned down, although a number of U-boats operated around the Cape of Good Hope at the time. A few days after Cappellini reached the East Indies, U-511 became the first U-boat to complete the voyage. This boat carried the Japanese naval attache Admiral Kichisaburō Nomura from Berlin to Kure. The boat was given to Japan as RO-500; its German crew returned to Penang to provide replacement personnel for the main submarine base being established at a former British seaplane station on the west coast of the Malayan Peninsula. A second base was established at Kobe; small repair bases were located at Singapore, Jakarta and Surabaya. As part of the dispersal of U-boat operations following heavy losses in the North Atlantic during the spring of 1943, Wilhelm Dommes was ordered to sail his U-178 from his operating area off South Africa to assume command at Penang.

Early submarine patrols to Penang

Japanese submarine I-30 sailed 22 August 1942 carrying German torpedoes, Torpedo Data Computer, search RADAR, Metox, hydrophone array, 50 Enigma machines and 240 Bolde SONAR countermeasure charges. She struck a mine and sank off Singapore on 13 October 1942. Barbarigo sailed in a cargo configuration on 17 June 1943 and was sunk by aircraft in the Bay of Biscay. Torelli sailed in a cargo configuration on 18 June 1943 and reached Penang on 27 August 1943. The Italian armistice with the allies became effective as the operation proceeded. The Italian submarine Ammiraglio Cagni surrendered at Durban, South Africa rather than continuing to Penang. The converted Italian cargo submarines were taken over by the German Navy (Kriegsmarine) and renumbered with UIT prefixes. U-200 sailed on 11 June 1943 and was sunk off Iceland by a PBY Catalina on 24 June. U-506 sailed on 6 July 1943 and was sunk by an American 1st A/S Squadron B-24 Liberator in the Bay of Biscay on 12 July. U-509 sailed on 3 July 1943 and was sunk by aircraft from USS Santee on 15 July. U-516 sailed on 8 July 1943 but returned to France on 23 August after transferring its fuel to other boats, enabling them to continue when their tanker was sunk. Ammiraglio Cagni sailed in combat configuration in early July 1943 but surrendered after the Italian armistice became effective on 8 September 1943. U-848 sailed on 18 September 1943 and sank the 4,600-ton British freighter Baron Semple before being sunk by US navy PB4Y Liberators in the South Atlantic on 5 November. U-849 sailed on 2 October 1943 and was sunk by a USN PB4Y Liberator in the South Atlantic on 25 November. Bagnolini sailed in a cargo configuration as UIT-22 on 26 January 1944 and was sunk off the Cape of Good Hope by RAF 262 Squadron Catalinas on 11 March. U-801 sailed on 26 February 1944 and was sunk by aircraft from USS Block Island on 16 March. U-851 sailed on 26 February 1944 with a cargo of mercury and 500 U-boat batteries, and disappeared in March 1944. U-843 sailed ón 18 February 1944 and sank the 8,300-ton British freighter Nebraska before reaching Jakarta on 11 June. U-860 sailed on 11 April 1944 and was sunk in the South Atlantic by aircraft from USS Solomons on 15 June.

Submarine patrols from Penang

Although operations from Penang had originally been envisioned as patrols along the trade routes while transporting strategic materials to Europe, many were turned back after allied patrols sank South Atlantic refueling assets.

Japanese submarine I-30 sailed on 22 April 1942 and reached France on 2 August.

Japanese submarine I-8 sailed on 27 June 1943 carrying tungsten and an extra crew for U-1224, and reached France in late August 1943. U-178 sailed 27 November 1943 with a cargo of 121 tons of tin, 30 tons of rubber and two tons of tungsten. She sank the 7,200-ton American Liberty ship Jose Navarro before reaching France on 25 May. U-532 sailed 4 January 1944 with a cargo of tin, rubber, tungsten, quinine and opium; and sank the 7,200-ton American Liberty ship Walter Camp two ships before returning to Penang after the refueling oiler Brake was sunk.

U-181 (type IXD2 cruiser) became I-501 and was scrapped at Singapore after Japan surrendered.

U-862 (type IXD2 cruiser) became I-502 and was scrapped at Singapore after Japan surrendered.

UIT-24 (originally Cappellini, then Aquilla III) became I-503 and was found at Kobe when Japan surrendered and scuttled by the US navy in Kii Suido.

UIT-25 (originally Torelli) became I-504 and was found at Kobe when Japan surrendered and scuttled by USN in Kii Suido.

U-219 (type XB minelayer) became I-505 and was scrapped at Jakarta after Japan surrendered.

U-195 (type IXD1 oiler) became I-506 and was scrapped at Jakarta after Japan surrendered.

Notes

External links

Monsun boats - U-boats in the Indian Ocean and the Far East - uboat.net

Category:Military units and formations of the Kriegsmarine Category:Monsoon Group