(IWASHIRO MARU, prewar)
IJN IWASHIRO MARU:
Tabular Record of Movement
© 2016 Gilbert Casse and Peter Cundall
19 March 1939:
Aioi. Laid down by Harima Zosensho K.K. shipyard for Kaiyo Kisen K.K. as a 3,550-tons cargo ship.
09 September 1939:
Launched and named IWASHIRO MARU. 
10 October 1939:
Completed and registered at Kobe.
10 November 1939 ~ 12 June 1940:
Chartered to Nakamura Kisen K.K.
13 June ~ 9 September 1940:
Chartered to Nichiro Gyogyo K.K.
21 September 1941:
Requisitioned by the IJN.
18 December 1941:
Loads 114.415-tons of ammunition.
20 December 1941:
Registered as an auxiliary collier/oiler attached to the Yokosuka Naval District with Yokosuka as homeport under Navy’s instruction No. 1699. Assigned to Vice Admiral (later Admiral) Inoue Shigeyoshi’s (37) Fourth Fleet as an auxiliary collier/oiler (Ko) category. That same day, Captain Madarame Kensuke (36) is appointed supervisor. 
27 December 1941:
Tsurumi. Starts conversion to military duty at Nihon Kokan Zosensho K.K. shipyard.
26 January 1942:
The conversion is completed.
E January 1942:
Assigned to ammunition transport missions under Fourth Fleet secret instruction No. 28.
7 February 1942:
E 11 ~ 15 February 1942:
Operates in the South Seas (Japanese Mandated islands).
18 February 1942:
Departs Yokosuka alone.
E 22 February ~ 12 March 1942:
Operates in the South Seas.
18 March 1942:
12 April 1942:
Arrives at Yokohama.
6 May 1942:
Departs Yokosuka with auxiliary collier KAMOI MARU. At 1430, departs Futtsu. Later that day, off the Izu Peninsula, the convoy is escorted by auxiliary gunboat (later auxiliary transport) HIYOSHI MARU No. 2 GO and auxiliary small minelayer TAKACHIHO MARU.
7 May 1942:
HIYOSHI MARU No. 2 GO ends escort.
19 May 1942:
Arrives at Kwajalein, Marshalls.
20 May 1942:
Supplies fresh water to small freighters FUDO MARU No. 2 and SEISHU MARU No. 2. Departs later.
E May 1942:
Arrives at Rabaul, New Britain.
3 June 1942:
Coals auxiliary gunboat NIKKAI MARU.
4 June 1942:
Coals auxiliary gunboat SEIKAI MARU.
5 July 1942:
Arrives at Yokohama. Departs later.
28 July 1942:
Departs Yokosuka for Kwajalein and then Rabaul.
1 September 1942:
Arrives at Yokosuka.
5 October 1942:
Captain Madarame is relieved by Captain (Rear Admiral posthumously) Asai Kenji (33).
8 October 1942:
23 November 1942:
Arrives at Yokohama.
10 December 1942:
Departs Yokohama for Niihama, Shikoku in West Convoy No. 63 also consisting of auxiliary transport KENRYU MARU, IJN requisitioned cargo ship (B-AK) WAZAN MARU and IJA transport MIKAGE MARU escorted by torpedo boat CHIDORI. The convoy assembles and at 0930, departs from Futtsu.
12 December 1942:
Arrives at Niihama. Departs later that day.
13 December 1942:
Departs Yokosuka for Truk, Central Carolines.
15 January 1943:
About 75 nautical miles E of Majuro, Marshalls. LtCdr John B. Azer’s (USNA ’28) USS WHALE (SS-239) running on the surface sights a large merchant ship. USS WHALE dives and closes range. Azer fires four Mark XIV Type 3A torpedoes and scores three hits on IWASHIRO MARU. The auxiliary collier/oiler has her stern broke off that immediately sinks. The remainder of the ship sinks within six minutes at 09-54N, 167-07E with the loss of 23 of her crew (probably all hands).
1 April 1943:
Removed from the Navy’s list under instruction No. 587.
 Not to be confused with civilian cargo ship (C-AK) (873 GRT ’43).
 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.
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