(KOAN MARU, prewar)

Tabular Record of Movement

© 2016-2018 Berend van der Wal, Gilbert Casse and Peter Cundall

Revision 2

13 March 1936:
Uraga. Laid down by Uraga Dockyard K.K. shipyard for Dairen Kisen K.K as a 3,462-tons cargo ship.

3 June 1936:
Launched and named KOAN MARU. [1]

27 August 1936:
Completed and registered at Dairen, Manchuria (now Dalian, northern China).

2 September 1936:
Departs Kobe for Dairen Ko (Port).

15 August 1941:
Requisitioned by the IJN.

5 September 1941:
Registered as an auxiliary water tanker, attached to the Sasebo Naval District under instruction No. 1025. That same day, Captain Noda Kenzo (36) is appointed supervisor.

25 September 1941:
Kobe. Conversion for military duty starts in the Kawasaki K.K. shipyard.

E October 1941:
Attached to Vice Admiral Takahashi Ibo’s (36) third fleet as an auxiliary water tanker, (Ko) category. [2]

25 October 1941:
The conversion is completed.

22 November 1941:
Embarks Philippines Operation invasion troops. Loads 2,687t of water and moves to the forward base location.

24 November 1941:
Departs Sasebo for southern China waters.

3 December 1941:
Departs Sasebo.

6 December 1941:
Arrives at Mako, Pescadores.

18 December 1941: The Invasion of the Philippines -“M” Operation (M Sakusen):
Departs Mako for Santo Tomas, Lingayen Gulf, Philippines as part of the Invasion of Lingayen Gulf, Philippines consisting of 72 transports in three echelons carrying the main part of LtGen Homma Masaharu's 80,000-man 14th Army. The first echelon is composed of 27 transports from Takao under Rear Admiral (later Vice Admiral) Hara Kenzaburo (37), the second echelon of 28 transports under Rear Admiral (later Vice Admiral) Nishimura Shoji (39) and the third echelon of 21 transports from Keelung under Rear Admiral (later Vice Admiral) Hirose Sueto (39).

23 December 1941:
Santo Tomas. Auxiliary gunboat KISO MARU comes alongside and is replenished with boiler water.

25 December 1941:
Auxiliary gunboats NAMPO and ASO MARUs come alongside and are replenished with boiler water.

26 December 1941:
At 1225 departs Santo Tomas in convoy with YODOGAWA and SENDAI MARUs and ten unidentified merchant ships escorted by auxiliary gunboats TAIKO, MANYO, OKUYO and KAMITSU MARUs.

28 December 1941:
At 1810 arrives at Takao, Formosa (Now Kaoshiung, Taiwan).

1 January 1942:
At 0800 departs Takao in a convoy also consisting of YODOGAWA, SENDAI, KOSEI, ASAYAMA, KIKU MARUs and KUREHA MARU No. 1 escorted by auxiliary gunboats TAIKO, MANYO, OKUYO and KAMITSU MARUs.

3 January 1942:
At 2039 arrives at Camiguin, Philippines. Departs later that same day at 2400.

8 January 1942:
At 1030 arrives at Davao, Philippines in same convoy. Departs later.

E January 1942:
Arrives at Tarakan, Borneo.

30 January 1942:
Replenishes auxiliary gunboat KAMITSU MARU with fresh water.

2 February 1942:
Departs Tarakan with SENDAI MARU escorted by auxiliary gunboat KAMITSU MARU.

5 February 1942:
Arrives at Davao. Auxiliary repair ship AKASHI starts engine repairs.

15 February 1942:
AKASHI completes engine repairs.

15 May 1942:
Scheduled to be fitted with one Type 92 7.7mm mod. A MG and 5 type 38 Arisaka rifles under Navy’s secret instruction No. 5990.

20 May 1942:
Attached to the Southern district auxiliary supply unit.

5 August 1942:
Attached to the Port Moresby, southern New Guinea invasion auxiliary supply unit. Arrives at Rabaul later.

22 August 1942:
Replenishes auxiliary gunboat SEIKAI MARU with water.

25 august 1942:
Attached directly to the Combined Fleet.

22 September 1942:
Replenishes auxiliary gunboat SEIKAI MARU with water.

27 October 1942:
At 1628, minesweeper W-22 comes alongside on port side. At 1648, starts supply of 26-tons of fresh water. At 1735, water supply is completed. At 1743, minesweeper W-22 disengages.

29 October 1942:
Replenishes auxiliary minesweeper FUMI MARU No. 2 with water.

1 December 1942:
Captain Noda is relieved and assigned to the Yokosuka Naval District. That same day KOAN MARU is rerated auxiliary water tanker (Otsu) category. [2]

13 January 1943:
Replenishes auxiliary transport NANKAI MARU with 300t water.

31 January 1943:
Departs Kashiwabara, Paramushiro (now Severo-Kurilsk, Paramushir), Kuriles.

4 February 1943:
Arrives at Attu island, Aleutians and unloads cargo.

February 1943:
Attached to the South Seas auxiliary supply unit.

5 March 1943:
At 0045 arrives at Zungen Point, Wide Bay, New Britain.

9 April 1943:
Departs Rabaul, in a convoy consisting of auxiliary oilers KYOEI MARU and HISHI MARU No. 2 and auxiliary storeship HARUNA MARU, escorted by subchaser CH-37.

10 April 1943:
CH-37 is detached and returns to Rabaul.

12 April 1943:
LtCdr (later Rear Admiral-Ret) Louis D. McGregor's (USNA ’30) USS PIKE (SS-173) attacks the convoy. KOAN MARU successfully evades a torpedo attack at 05-30N, 150-42E.

13 April 1943:
Two destroyers arrive as escort.

14 April 1943:
At 1040, arrives at Truk. Departs later.

29 April 1943:
Arrives at Yokosuka.

2 May 1943:
Departs Yokosuka.

7 May 1943:
Arrives at Sasebo.

17 May 1943:
Departs Sasebo.

18 May 1943:
Arrives at Shimonoseki.

15 June 1943:
Departs Shimonoseki.

16 June 1943:
Arrives at Sasebo.

18 June 1943:
Departs Sasebo.

20 June 1943:
Arrives at Kobe.

21 June 1943:
Departs Kobe.

23 June 1943:
Arrives at Yokosuka.

25 June 1943:
Departs Yokosuka in convoy No. 3625 also consisting of auxiliary passenger-cargo ship SHOZAN MARU and auxiliary transport TOYO MARUs escorted by auxiliary gunboat HEIJO MARU.

26 June 1943:
About 20 nms W of Hachijo Jima, Izu Shoto (Izu Islands). LtCdr (later RearAdmiral-Ret) Thomas M. Dykers’ (USNA ’27) USS JACK (SS-259) sights the convoy. About 0427, Dykers torpedoes and hits TOYO MARU aft, at 33-13N, 139-30E. She sinks 30 minutes later sustaining only one casualty. KOAN MARU rescues survivors.

Later, Dykers torpedoes and sinks IJN requisitioned passenger-cargo (5,859 GRT) SHOZAN MARU about the same position. 60 crewmen are KIA. In attempting to torpedo KOAN MARU, USS JACK is shaken by a torpedo dropped by a Japanese aircraft and makes a crash-dive. Her crew manages to correct her dangerous diving angle and effects emergency repairs.

6 July 1943:
Arrives at Truk, Central Carolines.

9 July 1943:
At 0900, departs Truk in convoy No. 1091 escorted by subchaser CH-28. The convoy sails at 12.5 knots.

12 July 1943:
Arrives at Rabaul.

13 July 1943:
Departs Rabaul for Massava twice on fresh water transport missions. (Massava Bay in East New Britain appears to have been a good natural fresh water source).

12 August 1943:
Replenishes auxiliary storeship TAKUNAN MARU with water.

23 August 1943:
Departs Rabaul for Massava twice on fresh water transport missions.

September 1943:
Departs Rabaul for Massava 5 times on fresh water transport missions.

October 1943:
Departs Rabaul for Massava 5 times on fresh water transport missions.

7 October 1943:
At Rabaul replenishes auxiliary oiler KYOEI MARU with boiler water.

November 1943:
Departs Rabaul for Massava 7 times on fresh water transport missions.

14 November 1943:
Replenishes auxiliary transport KANAYAMASAN MARU with fresh water.

21 November 1943:
Replenishes auxiliary repair ship HAKKAI MARU with fresh water.

28 November 1943:
Replenishes again auxiliary repair ship HAKKAI MARU with fresh water.

24 January 1944:
Simpson harbor, Rabaul at (S05-15S, 152-40E), sustains an airstrike by US Marine Corps TBFs, New Zealand’s No. 15 fighter squadron and No. 1 bomber reconnaissance Squadron.

USMC TBFs, supported by USN, USMC, USAAF and RNZAF Curtiss P-40E "Kittyhawk" fighters, again attack shipping and sink LYONS (casualties unknown), YAMAYURI (three crewmen KIA), KOAN (47 crewmen and 13 passengers KIA) and TAISHO MARUs (four crewmen KIA) and damage Fleet oiler NARUTO.

10 March 1944:
Removed from the Navy list under internal order No. 427.

Authors notes :
[1] Not to be confused with civilian tanker (885 GRT, ’37), civilian cargo ship (884 GRT, ’45), Government (Dept. of Railways) ferry-boat (7,103 GRT, ’37), civilian passenger ship (661 GRT, ’13), IJA transports No. 586 (4,306 GRT, ’05) and No. 38 (3,184 GRT, ’24).

[2] There were two categories of Kyusuisen. (Ko) category with an IJN Captain as supervisor aboard and (Otsu) category without.

Thanks go to Gengoro S. Toda of Japan.

Berend van der Wal, Gilbert Casse and Peter Cundall.

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