(KOSEI MARU, prewar)
IJN KOSEI MARU:
Tabular Record of Movement
© 2016-2018 Gilbert Casse and Peter Cundall
22 April 1932:
Nagasaki. Laid down by Mitsubishi Zosen K.K. shipyard for Hiroumi Shoji K.K. as a 6,665-tons cargo ship.
15 January 1933:
Launched and named KOSEI MARU. 
17 March 1933:
Completed and registered at Kobe. Her Gross Registered tonnage (GRT) and Net Registered Tonnage (NRT) respectively are 6,665-tons and 4,765-tons. 
Her GRT and NRT are respectively changed to 6,667-tons and 4,767-tons. 
19 November 1941:
Requisitioned by the IJN.
20 November 1941:
Nagasaki. Conversion to military duty starts at Mitsubishi Heavy Industries K.K shipyard.
8 December 1941:
The conversion is completed.
10 December 1941:
Registered as an auxiliary collier/oiler attached to the Sasebo Naval District with Sasebo as homeport under Navy’s instruction No. 1634. Assigned to Vice Admiral Takahashi Ibo’s (36) Third Fleet as an auxiliary collier (Ko) category. That same day, Captain Takahashi Eikichi (36) is appointed supervisor. 
E January 1942:
Arrives at Davao, Mindanao.
9 January 1942:
Comes alongside and coals auxiliary gunboats MANYO, TAIKO and OKUYO MARUs.
10 January 1942:
Coals auxiliary gunboat KAMITSU MARU.
30 January 1942:
Comes alongside and coals auxiliary gunboat OKUYO MARU.
31 January ~ 1 February 1942:
Comes alongside and coals auxiliary gunboats MANYO and TAIKO MARUs.
7 February 1942:
Comes alongside and coals auxiliary gunboat KAMITSU MARU.
Departs Davao escorted by destroyer AMATSUKAZE.
11 February 1942:
13 February 1942:
At 1400 departs Bangka for Ambon, Moluccas in convoy also consisting of KIKU, GIYO, TENRYU, NANIWA and CHOZAN MARUs escorted by destroyer AMATSUKAZE and auxiliary gunboat OKUYO MARU.
Meets up with water tanker ASAYAMA MARU escorted by auxiliary gunboat OKUYO MARU.
14 February 1942:
Arrives at Ambon, Moluccas.
22 February 1942:
25 February 1942:
Arrives at Davao. Departs later.
7 March 1942:
Departs Takao, Formosa (now Kaohsiung, Taiwan).
10 March 1942:
Arrives at Cam Ranh Bay, French Indochina (now Vietnam). Hits a Japanese mine and sinks with the loss of two crewmen, two gunners and nine passengers.
1 April 1942:
Removed from the Navy’s list under instruction No. 562.
 Numerous ships bore this name like auxiliary transports (2,205 GRT ’24) and (3,551 GRT ’37), auxiliary storeship (8,266 GRT ’20), auxiliary small minelayer (1,026 GRT ’15), IJA transports No. 889 (1,943 GRT ’43) and No. 1031 (865 GRT ’40), Okada Shosen cargo ship (3,262 GRT ’19) and other smaller vessels.
 NRT is a ship's cargo volume capacity expressed in "register tons", one of which equals to a volume of 100 cubic feet (2.83 m3). It is calculated by reducing non-revenue-earning spaces i.e. spaces not available for carrying cargo, for example engine rooms, fuel tanks and crew quarters, from the ship's gross register tonnage (GRT). Net register tonnage (NRT) is not a measure of the weight of the ship or its cargo, and should not be confused with terms such as deadweight tonnage or displacement.
 There were two categories of Kyutanyusen. (Ko) category with an IJN Captain as supervisor aboard and (Otsu) category without.
Thanks go to Gengoro S. Toda of Japan.
- Gilbert Casse and Peter Cundall.
Back to the Collier-Tankers Page