The was a class of oceanographic research ship/weather ship of the Imperial Japanese Navy (IJN), serving during World War II. The IJN official designation was .
Construction In 1938, the IJN wanted to investigate the weather and ocean currents in a potential future battlefield. Kaiyō No. 1-class ships were built for the purpose. The IJN made Hokkaido Fisheries Research Institute San'yō Maru a sample for the Kaiyō No. 1. All ships were deployed in the Hydrographic Department, and they were directly controlled by the Naval Ministry. Therefore, being government ships, they raised civil ensign, not the naval ensign. The crew were civil servants except for several warrant officers.
All sister ships were built by Mitsubishi Heavy Industries at Shimonoseki shipyard.
Ships in classes Ship Laid down Launched Completed Fate 1 March 1939 1 July 1939 9 October 1939 Sunk by air raid off Derawan Island JACAR C08030773600, p. 4 on 19 October 1944. 1 July 1939 4 October 1939 23 December 1939 Sunk by Hr. Ms. Zwaardvisch off Rembang JACAR C08030773600, p. 26 on 15 October 1944. 3 March 1941 22 October 1941 17 June 1942 Missing in action in late 1944; removed from naval ship list on 29 October 1944. 23 May 1941 20 January 1942 17 July 1942 Survived war at Uraga;JACAR C08011043700, p. 2 transferred to Ministry of Transport on 29 November 1945; transferred to Maritime Safety Agency on 1 May 1948 (hull number HG-01, later HM-01); renamed on 20 October 1949; renamed on 15 December 1956; retired on 26 March 1964. 6 April 1942 12 November 1942 28 February 1943 Survived war at Kasaoka; transferred to Ministry of Transport on 29 November 1945; transferred to Maritime Safety Agency on 1 May 1948 (hull number HG-02, later HM-02); renamed on 20 October 1949; sunk by jets of water and tephra"bayonnaise Rocks Volcano" at volcanodiscovery.com (retrieved 10 October 2012) from the eruption of Myōjin-shō on 24 September 1952; struck on 27 April 1953. 6 April 1942 12 December 1942 31 March 1943 Sunk by USS Gabilan off Muroto on 31 October 1944.
See also Ministry of the Navy of Japan
References
Further reading Monthly Ships of the World No.613, Special issue "All ships of Japan Coast Guard 1948–2003", , (Japan), July 2003 Jirō Kimata, Introductory book of the Japanese small vessels, Kōjinsha (Japan), December 1999 30 year History of Japan Maritime Safety Agency, Policy and Legal Affairs Division-Japan Maritime Safety Agency (JMSA), May 1979 75 year History of Mitsubishi Heavy Industries-Shimonoseki shipyard, Mitsubishi Heavy Industries-Shimonoseki shipyard, 1964 Shizuo Fukui, FUKUI SHIZUO COLLECTION "Japanese Naval Vessels 1869–1945", KK Bestsellers (Japan), December 1994 , National Archives of Japan Reference code: C08011043700, Ships and boats list Reference code: C08030773600, Data relevant to Daiichi-Kaiyo-maru (No.1) and Daini-Kaiyo-maru (No.2), October 1944