Hōkoku Maru

Hōkoku Maru was laid down at the Tama shipyard in Okayama Prefecture prior to the outbreak of World War II. She was designed as a cargo liner for the Osaka Shosen Lines's regularly scheduled services to South America. Ostensibly a luxury ocean liner, the design boasted a luxury suite of rooms, known as the Nara Suite after the city of that name. However the military had a say in the design of Hōkoku Maru, with an eye towards her future use as a troop transport, was built with large government subsidies provided from 1936 onwards.[1]

Hōkoku Maru′s capacity was just under 10,500 gross register tons, with a length of 160.8 m (527 ft 7 in). Powered by two Mitsui B&W diesel engines with 13,000 shp (9,700 kW) driving twin screws, she was capable of 20.9 knots (24.1 mph; 38.7 km/h).

Hōkoku Maru was launched on 5 July 1939 and completed in June 1940.

Hōkoku Maru entered service in July 1940 and made several voyages to Manchukuo the Japanese-controlled puppet state in Manchuria, before being requisitioned in August 1941 for conversion into an armed merchant cruiser. Taken in hand at the Mitsubishi Heavy Industries Yard at Kobe, Hōkoku Maru was equipped with four 15 cm/50 41st Year Type guns, two QF 12 pounder 12 cwt naval guns, two Type 93 13.2-mm machine guns and two twin-mount 533-millimetre (21 in) torpedo tubes. In October 1941 she was fitted with powerful searchlights and a boom for handling a Kawanishi E7K (Allied reporting name "Alf") floatplane, with one additional aircraft as a spare.

Despite her intended role as a commerce raider, the Japanese made little attempt to disguise Hōkoku Maru as a simple merchant ship; Hōkoku Marus guns were fitted with gun-shields and were left in open sight,[2] while her paint scheme was a two-tone camouflage design.

Hōkoku Maru was commissioned into the Imperial Japanese Navy on 20 September 1941 under the command of Captain Aihara Aritaka.[1]

On 15 November 1941 Hōkoku Maru, in company with her sister ship Aikoku Maru, sailed for Jaluit in preparation for the opening of hostilities against the United States. On 7 December 1941 the two ships were in the Tuamotu Archipelago at the start of a two-month raiding voyage that sank two Allied merchant ships, SS St Vincent off Pitcairn Island and SS Malama near the Cook Islands, before returning to Japan in February 1942.

In Japan, Hōkoku Maru underwent a refit, and was re-armed with 8 x 140mm (5.5 inch) guns. She was also outfitted as a submarine tender in order to support operations by the IJN's 8th Submarine Squadron off East Africa.

In May 1942, Hōkoku Maru, again in company with Aikoku Maru, sailed for Singapore, thence to the Indian Ocean. There they sank the Dutch tanker Genota south of Diego-Suarez, Madagascar, and the British cargo ship Elysia south of the Mozambique Channel before re-arming the submarines of the 8th Submarine Squadron off the east coast of Africa.

In July 1942 the two raiders captured the New Zealand cargo ship Hauraki, which they sent to Singapore under a prize crew. Returning to Singapore, Hokoku Maru was re-equipped with two Aichi E13A (Allied reporting name "Jake") floatplanes, and an experimental two-tone dazzle camouflage scheme.

In November 1942 Hōkoku Maru, again in company with Aikoku Maru, departed Singapore for the Indian Ocean, on what would be her last raiding voyage.[1]

On 7 November 1942 Hōkoku Maru and Aikoku Maru passed through the Sunda Strait into the Indian Ocean. Four days later, on 11 November 1942, they encountered the Dutch armed tanker Ondina, escorted by the Royal Indian Navy corvette HMIS Bengal off the Cocos (Keeling) Islands. As Hōkoku Maru engaged, Bengal and Ondina returned fire, and a shell, probably from Ondina's single 4-inch (102 mm) gun, hit Hōkoku Maru's starboard torpedo mount, causing an explosion and uncontrollable fire which spread to the aft magazine. After a series of explosions, Hōkoku Maru sank just two hours after the action commenced. Aikoku Maru rescued 278 of her crew. Both Ondina and Bengal escaped.[1][3]

• Gardiner R, Chesnau R: Conway's All the World's Fighting Ships 1922–1946 (1980) ISBN 0-85177-146-7
• Kindell D, Action of the Bengal and Ondina November 1942 at navalhistory.net; retrieved 13 December 2018
• Hackett B, Kingsepp S, Hokoku Maru at combinedfleet.com; retrieved 13 December 2018