Ship History
Built by Kawaminami Kogyo Zosensho K. K at Koyagi Jima. During 1939, laid down as a 1,913 ton Peacetime Standard (D) Type cargo ship for Amakasu Sangyo K. K. Launched on August 16, 1939 and named Amakasu Maru No. 1. Completed February 6, 1940. On March 31, 1941 requisitioned by the Imperial Japanese Navy (IJN) as a general requisitioned transport (Ippan Choyosen).

Departed Japan and on June 1, 1941 arrived at Jaluit then to Eniwetok departing on June 20. On July 17, 1941 returns to Jaluit and supplies water to auxiliary gunboat Chokai Maru on that day and again four days later. On July 22, 1941 supplies water to Nagata Maru and again three days later then departs for Eniwetok and leaves on July 29. On August 27, 1941 arrives at Kwajalein and supplies water to gunboat Daido Maru on September 18 and auxiliary gunboat Ikuta Maru then departs that same day.

On October 15, 1941 designated as an auxiliary water tanker attached to the Yokosuka Naval District under instruction No. 1256. Ten days later arrives at Saipan, then on November 13 at Kwajalein and supplies water to gunboat Ikuta Maru. On November 15 at Pekeji supplies water to gunboat Daido Maru.

On December 1, 1941 assigned to the Fourth Fleet, 6th Base Force, Marshall defense water supply unit as an auxiliary water tanker, Otsu category.

Wartime History
At the start of the Pacific War on December 8, 1941 departs Saipan and arrives Kwajalein the same day and departs on December 11-12 at Roi then to Kwajalein until December 19 then to Jaluit on December supplies water to auxiliary gunboat Ikuta Maru and departs on December 23 arriving at Emiedj the same day.

24 December 1941: Departs Emiedj.

25 December 1941: Arrives at Kwajalein.

29 December 1941: Departs Kwajalein.

2 January 1942: Departs Kwajalein.

8 January 1942: Arrives at Roi.

10 January 1942: Departs Roi and arrives at Kwajalein later that same day.

16 January 1942: Departs Kwajalein.

17 January 1942: Arrives back at Kwajalein.

23 January 1942: Departs again Kwajalein.

24 January 1942: Arrives at Emiedj.

29 January 1942: Departs Emiedj and arrives later at Kwajalein.

7 February 1942: Departs Kwajalein and arrives at Roi later that day.

9 February 1942: Departs Roi and arrives at Kwajalein later in the day.

10 February 1942: Departs Kwajalein.

13 February 1942: Arrives at Ponape.

19 February 1942: Departs Ponape.

22 February 1942: Arrives at Kwajalein.

26 February 1942: Departs Kwajalein.

27 February 1942: Arrives at Emiedj. Replenishes auxiliary gunboat IKUTA MARU with fresh water.

1 March 1942: Departs Emiedj.

2 March 1942: Arrives at Kwajalein.

4 March 1942: Departs Kwajalein for a patrol mission in Gea Pass, Kwajalein atoll. [2]

7 March 1942: Arrives at Rongelap, Marshalls.

9 March 1942: Departs Rongelap.

11 March 1942: Arrives at Borak, Marshalls. Departs the same day.

15 March 1942: Arrives at Ponape.

27 March 1942: Departs Ponape.

30 March 1942: Arrives at Kwajalein.

1 April 1942: Replenishes auxiliary patrol craft RYUJIN MARU No. 3 with fresh water. Thereafter departs Kwajalein and arrives at Roi later that day.

2 April 1942: Departs Roi.

3 April 1942: Arrives at Roi. Auxiliary patrol boat HIGASHI NIHON MARU come alongside and is replenished with 13t of water.

4 April 1942: Departs Roi.

5 April 1942: Arrives at Taroa, Maloelap, Marshalls.

6 April 1942: Departs Taroa.

7 April 1942: Arrives at Jabot, Marshalls.

9 April 1942: Departs Jabot.

10 April 1942: Arrives at Kwajalein.

13 April 1942: Departs Kwajalein.

15 April 1943: Arrives at Ponape.

21 April 1942: Departs Ponape.

25 April 1942: Arrives at Kwajalein. Replenishes small freighter SEIJU MARU No. 2 with 16t of water.

26 April 1942: Departs Kwajalein.

27 April 1942: Arrives at Wotje, Marshalls.

28 April 1942: Auxiliary patrol craft FUKUYOSHI MARU No. 5 and ASHITAKA MARU No. 5 come alongside. Replenishes FUKUYOSHI MARU No. 5 with fresh water and ASHITAKA MARU No. 5 with 15t of fresh water. Thereafter departs Wotje later in the day.

29 April 1942: Arrives at Taroa.

30 April 1942: Arrives at Emiedj.

1 May 1942: Auxiliary gunboat IKUTA MARU comes alongside and is replenished with fresh water.

2 May 1942: Resumes replenishing of IKUTA MARU with fresh water. Thereafter departs Emiedj.

5 May 1942: Arrives at Ponape.

10 May 1942: Departs Ponape.

13 May 1942: Arrives at Kwajalein. Replenishes small freighter SEIJU MARU No. 2 with 20t of fresh water.

15 May 1942: Departs Kwajalein.

16 May 1942: Arrives at Taroa.

17 May 1942: Departs Taroa.

18 May 1942: Arrives at Wotje. Auxiliary patrol boat HIGASHI NIHON MARU comes alongside and is replenished with 5t of fresh water.

19 May 1942: Departs Wotje.

21 May 1942: Arrives at Borak. Departs later that day.

23 May 1942: Arrives at Roi.

25 May 1942: Departs Roi and arrives at Kwajalein later that same day.

10 June 1942: Departs Kwajalein.

13 June 1942: Arrives at Ponape.

19 June 1942: Departs Ponape.

22 June 1942: Arrives at Kwajalein.

27 June 1942: Departs Kwajalein for Japan.

9 July 1942: Arrives at Yokosuka.

12 July 1942: Transfers to Yokohama.

13 July 1942: Enters drydock.

14 August 1942: Undocked. Departs Yokohama and arrives at Yokosuka later in the day.

16 August 1942: Departs Yokosuka.

28 August 1942: Arrives at Kwajalein.

1 September 1942: At 1430, departs Kwajalein.

4 September 1942: Arrives at Ponape.

9 September 1942: Departs Ponape.

12 September 1942: At 0500, arrives at Kwajalein.

15 September 1942: At 0900, departs Kwajalein.

16 September 1942: Arrives at Wotje.

17 September 1942: Replenishes auxiliary patrol boat HIGASHI NIHON MARU with 2t of fresh water.

18 September 1942: Departs Wotje and arrives at Taroa later that day.

20 September 1942: Departs Taroa.

21 September 1942: Arrives at Emiedj.

23 September 1942: Departs Emiedj.

24 September 1942: At 1200, arrives at Kwajalein.

25 September 1942: At 0510, departs Kwajalein.

28 September 1942: At 0530, arrives at Ponape escorted by auxiliary subchasers SHONAN MARU No. 3 and TAMA MARU No. 3.

2 October 1942: Departs Ponape.

5 October 1943: At 0530, arrives at Kwajalein.

7 October 1942: Departs Kwajalein.

8 October 1942: Arrives at Taroa.

9 October 1942: Departs Taroa and arrives at Wotje later that day. Replenishes auxiliary patrol craft I-GO NICHIEI MARU with 2t of fresh water.

10 October 1942: Auxiliary patrol craft ASHITAKA MARU No. 5 comes alongside and is replenished with fresh water. Thereafter departs Wotje.

11 October 1942: Arrives at Kwajalein.

13 October 1942: Departs Kwajalein.

16 October 1942: Arrives at Ponape.

23 October 1942: Departs Ponape.

26 October 1942: Arrives at Jaluit.

8 November 1942: Departs Jaluit.

11 November 1942: Arrives at Ponape.

17 November 1942: Departs Ponape.

20 November 1942: Arrives at Kwajalein.

25 November 1942: Departs Kwajalein and arrives at Roi later that same day.

26 November 1942: Departs Roi.

27 November 1942: Arrives at Wotje. Replenishes auxiliary patrol craft KAZU MARU No. 5 with fresh water and ASHITAKA MARU No. 5 with 20t of fresh water.

28 November 1942: Departs Wotje.

29 November 1942: Arrives at Taroa. Departs later.

20 December 1942: Arrives at Rongelap. Departs later.

Sinking History
On December 24, 1942 departs Wake Island bound for Ponape. Soon after departing at 9:00am, USS Triton SS-201 fired torpedoes that hit and sank Amakasu Maru roughly two nautical miles south-southwest of Wake Island at roughly Lat 19-16N, Long 166-37E. During the sinking, twevle of her crew are lost. Officially, this vessel was removed from the Navy's list by internal order No. 108 on February 1, 1943.

Shipwreck
On August 11, 2016 NOAA Okeanos Explorer discovered a large shipwreck on seafloor that proves to be this vessel. The name "Amakasu Maru" is visible on the bow.

References
Combined Fleet - IJN AMAKASU MARU No. 1: Tabular Record of Movement
Okeanos Explorer - Dive 9: WWII Japanese Shipwreck August 10, 2016

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Last Updated
December 19, 2021