ZATSUYOSEN!

(CHOAN MARU, prewar)

IJN CHOAN MARU No. 2 GO: Tabular Record of Movement


© 2014-2015 Gilbert Casse, Bob Hackett and Peter Cundall

Revision 1


26 April 1926:
Aioi. Laid down by Kobeseikosho Harima Zosen Kojo K.K. shipyard for Osaka Shosen K.K. (OSK) as a 2,611-tons refrigerated passenger/cargo ship.

18 December 1926:
Launched and named CHOAN MARU.

31 March 1927:
Completed and registered in Osaka. Her Gross Registered Tonnage (GRT) and Net Registered Tonnage (NRT) respectively are 2,611-tons and 1,403-tons. [1]

6 April 1927:
Departs Kobe and arrives at Tianjin, northern China.

5 July 1931:
Runs aground near Shibotsu-To, Chosen (now South Korea). Self-refloating attempt is successful.

12 January 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

26 January 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

9 February 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

23 February 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

8 March 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

23 March 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

5 April 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

19 April 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

3 May 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

17 May 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

31 May 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

14 June 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

28 June 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

12 July 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

26 July 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

9 August 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

23 August 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

6 September 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

20 September 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

5 October 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

19 October 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

3 November 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

16 November 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

30 November 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

14 December 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

28 December 1935:
Departs Kobe ~ Arrives at Tianjin ~ Departs there and arrives at Kobe. (scheduled voyage).

24 February 1936:
Requisitioned by the IJA as a general requisitioned transport assigned to transport troops to the Kwantung Army Area.

5 March 1936:
Released to her owners.

1937:
Her GRT and NRT are respectively changed to 2,631-tons and 1,388-tons. [1]

7 January 1939:
Departs Kobe ~ arrives at Tanggu, northern China. (According to timetable)

21 January 1939:
Departs Kobe ~ arrives at Tanggu, northern China. (According to timetable)

1 September 1939:
Her owners are changed to Toa Kaiun K.K and registry port to Tokyo.

6 November 1941:
Requisitioned by the IJN.

8 November 1941:
Yokohama. Begins conversion to military duty at Mitsubishi Heavy Industries shipyard.

1 December 1941:
Registered in the IJN as an auxiliary gunboat attached to the Yokosuka Naval District under Navy’s instruction No. 1570. Navy Lt (Reserve) Rizuka Chuichi is appointed CO.

5 December 1941:
The conversion is completed.

9 December 1941:
Departs Yokohama on trials and arrives back there later that day.

10 December 1941:
Departs Yokohama and arrives at Yokosuka later that same day. Renamed CHOAN MARU No. 2 GO under Navy secret instruction No. 11623. Attached to Vice Admiral (later Admiral) Inoue Shigeyoshi’s (37) Fourth Fleet, in Vice Admiral Moizumi Shinichi’s (37) 4th Base Force, 6th Gunboat Division under instruction No. 1618-1. Hoists Navy Warship ensign.

11 ~ 14 December 1941:
Loads quartermaster items.

12 December 1941:
Loads ammunition.

15 ~ 16 December 1941:
Loads fuel.

17 December 1941:
Departs Yokosuka.

25 December 1941:
Arrives at Truk, Central Carolines.

26 December 1941:
Assigned to 4th Base Force, Guard Force.

27 ~ 28 December 1941:
Unloads consigned goods and other sundries.

2 January 1942:
Loads fresh water.

3 January 1942:
Departs Truk on convoy escort duty.

4 January 1942:
Arrives back at Truk.

5 January 1942:
Departs Truk on patrol duty, Northeast waters.

19 January 1942:
Engages in ASW combat against an unidentified submarine.

22 January 1942:
Arrives at Truk.

23 January 1942:
Comes alongside and replenishes water from auxiliary ammunition ship TATSUTAKE MARU.

24 January 1942:
Loads provisions and fuel.

25 January 1942:
Comes alongside and replenishes boiler water from auxiliary water carrier WAYO MARU.

26 January 1942:
Departs Truk.

28 January 1942:
Arrives at Greenwich Island, Kapingamarangi Atoll, Central Carolines. Disembarks 17th Air Flotilla personnel and related equipment. Departs later in the day.

29 January 1942:
Rated as the 61st auxiliary gunboat.

30 January 1942:
Arrives at Truk.

3 February 1942:
Departs Truk.

4 February 1942:
On patrol in northern channel.

9 February 1942:
Arrives back at Truk.

10 February 1942:
Comes alongside and replenishes water from auxiliary transport TONAN MARU No. 2.

11 February 1942:
Loads fuel.

15 February 1942:
Departs Truk on patrol duties in northern channel.

23 February 1942:
Arrives back at Truk. Loads fuel.

24 February 1942:
Loads shells. Departs Truk on ASW duties.

25 February 1942:
On patrol in northern channel.

26 February 1942:
Arrives back at Truk.

27 February 1942:
Loads provisions, fuel and fresh water.

28 February 1942:
Departs Truk on patrol duties in northern channel.

6 March 1942:
Engages in searching mission for missing auxiliary oiler KAIJO MARU No. 2 GO. [2]

8 March 1942:
Arrives at Truk.

9 March 1942:
Loads provisions and fresh water.

10 March 1942:
Loads fuel and fresh water.

11 March 1942:
Departs Truk on patrol duties in southern channel.

15 March 1942:
Arrives back at Truk.

18 March 1942:
Loads provisions.

19 March 1942:
Loads fuel.

21 March 1942:
Loads fuel. Departs Truk escorting a convoy bound for Rabaul, consisting of auxiliary transports CHOWA, SHOKA and AKIBASAN MARUs.

24 March 1942:
At some point, destroyer MOCHIZUKI takes over convoy escort.

26 March 1942:
Arrives back at Truk.

28 March 1942:
Departs Truk on northern channel patrol duties.

2 April 1942:
Arrives back at Truk.

3 ~ 5 April 1942:
Loads fresh water.

6 April 1942:
Loads fuel and provisions.

10 April 1942:
Released from 6th Gunboat Division under instruction No. 652. Attached to Fourth Fleet, 4th Base Force, Guard Force under Navy’s secret instruction No. 10.

12 April 1942:
Departs Truk on patrol duties.

17 April 1942:
Arrives back at Truk.

22 April 1942:
Departs Truk on patrol duties.

27 April 1942:
Arrives back at Truk.

30 April 1942:
Departs Truk on patrol duties.

E 2 ~ 4 May 1942:
Engages in ASW search operation and a ditched aircraft rescue mission.

5 May 1942:
Arrives back at Truk. Departs later in the day on patrol duties.

8 May 1942:
Arrives back at Truk.

11 May 1942:
Departs Truk and arrives back there later that day.

18 May 1942:
Departs Truk on rescue mission and engages in towing together with auxiliary gunboat HEIJO MARU, damaged auxiliary oiler GOYO MARU back to Truk. [3]

22 May 1942:
Arrives at Truk, still towing GOYO MARU. Departs later that day on patrol duties.

27 May 1942:
Arrives back at Truk.

29 May 1942:
Departs Truk escorting civilian cargo ship (C-AK) PALAU MARU.

E 30 May 1942:
Escorts IJA transport OMI MARU to Truk.

31 May 1942:
Arrives at Truk.

13 June 1942:
Departs Truk on escort duties.

16 June 1942:
Arrives back at Truk.

25 June 1942:
Departs Truk.

26 June 1942:
Arrives back at Truk.

2 July 1942:
Departs Truk.

10 July 1942:
Arrives at Yokosuka.

E 11 July ~ 6 August 1942:
Undergoes hull, engine and weapons maintenance and repairs.

7 August 1942:
Departs Yokosuka.

15 August 1942:
Picks up 54 survivors from lifeboat No. 7 of auxiliary transport BRASIL MARU at 08-31N, 149-16E. [4]

17 August 1942:
Arrives at Truk.

23 August 1942:
Departs Truk on escort duties.

26 August 1942:
Arrives back at Truk.

27 August 1942:
Departs Truk on escort duties.

29 August 1942:
Picks up 53 survivors from lifeboat No. 17 of auxiliary transport BRASIL MARU at 11-26N, 147-58E. [4].

30 August 1942:
Arrives at Truk outer anchorage.

31 August 1942:
Departs Truk outer anchorage and arrives at Truk. Departs there later that same day.

E 3 September 1942:
Arrives at Rabaul, New Britain.

October 1942:
Based at Palau, Western Carolines. Engages in IJA convoys escort duties back and forth between Rabaul, Manila, Hong Kong, Saigon, Surabaya and Palau.

November 1942:
Based at Palau. Engages in IJA convoys escort duties back and forth between Rabaul, SW Pacific locations and Palau.

5 November 1942:
At 0800 departs Rabaul for Palau escorting a mixed convoy consisting of IJN Submarine depot Ship YASUKUNI MARU, IJN ammunition ship TATSUTAKE MARU, Army cargo ship TAIFUKU MARU and civilian (3011 ton) EIKO MARU. The convoy sails at 10 knots.

12 November 1942:
Arrives at Palau.

23 November 1942:
At 1200 submarine chasers CH-16 and CH-18 meet up with incoming Army convoy A (No.8 Military Movement) consisting of GENMEI and KOCHI MARUs then escorted by auxiliary gunboat CHOAN MARU No. 2 GO.

24 November 1942:
At 1500 the convoy arrives at Rabaul. It is not clear if CHOAN MARU No. 2 GO accompanied the convoy to Rabaul or returned to Palau after rendezvous.

December 1942:
In Palau waters.

January 1943:
Bolsters the escort of ‘No. 6 Go Transportation Operation’ Part C convoy that departed Mako, Pescadores on 5 Jan ’43, consisting of IJA transports MEIU, SHINAI, SOMEDONO and SURABAYA MARUs escorted by destroyers HOKAZE, NAGATSUKI, SHIRAYUKI and subchaser CH-11.

19 January 1943:
Arrives at Truk. Departs at 0800, still escorting Part C convoy. NNE of Buin, Bougainville, LtCdr Jack H. Lewis’ (USNA ’27) USS SWORDFISH (SS-193) attacks Part A of the convoy consisting of IJA transports MYOHO, TEIYO MARUs and SHINSEI MARU No. 1. USS SWORDFISH sinks MYOHO MARU at 05-38S, 156-20E. Of the 922 IJA troops and 35 IJN passengers she was carrying, 61 and three crewmen are KIA.

20 January 1943:
286 miles from Truk. LtCdr (later Rear Admiral-Ret) Creed C. Burlingame’s (USNA ’27) USS SILVERSIDES (SS-236) attacks Part C of the convoy. USS SILVERSIDES sinks MEIU MARU and damages heavily SURABAYA MARU at 03-52N, 153-56E. MEIU MARU was carrying 2,997 men of the 23rd Infantry Regiment, 6th Division. 401 men are KIA. On SURABAYA MARU, 36 crewmen and 463 soldiers are KIA. CHOAN MARU No. 2 GO and subchaser CH-11 rescue survivors and engage in ASW sweep. Later, destroyer ASAGUMO arrives from Truk and scuttles SURABAYA MARU. That same day, Part A arrives at Shortland Islands anchorage.

24 January 1943:
Arrives back at Truk.

25 January 1943:
Departs Truk on convoy escort and victim search duties.

30 January 1943:
Arrives at Palau.

4 February 1943:
Departs Palau on escort duties.

6 February 1943:
Arrives back at Palau.

9 February 1943:
Departs Palau on escort duties.

18 February 1943:
Arrives back at Palau.

21 February 1943:
Departs Palau on escort duties.

1 March 1943:
Arrives back at Palau.

4 March 1943:
Departs Palau on escort duties.

6 March 1943:
Arrives back at Palau.

E 7 ~ 16 March 1943:
Undergoes repairs.

17 March 1943:
Departs Palau for Truk on convoy escort duties.

20 March 1943:
Off Woleai Atoll, Central Carolines. LtCdr (later Rear Admiral) Roy S. Benson’s (USNA ’29) USS TRIGGER (SS-237) running submerged, sights a convoy of four merchant ships on periscope. About 1400, Benson attacks the lead ship, firing a spread of three Mark XIV Type 3A torpedoes. One hit is scored at 03-48N, 144-12E on portside but is a low detonation hit. CHOAN MARU No. 2 GO lists 10 degrees to port and stops briefly before resuming again her course, rejoining the convoy.

21 March 1943:
At 1040, minesweeper W-8 departs Truk to assist CHOAN MARU No. 2 GO.

22 March 1943:
Destroyer SAMIDARE bolsters the escort.

23 March 1943:
At some point, SAMIDARE detaches from the convoy, being replaced by minesweeper W-8.

27 March 1943:
Arrives at Truk.

4 April 1943:
At 0600, departs Truk for Japan escorting convoy consisting of auxiliary oiler HOYO MARU, auxiliary collier/oiler TONEI MARU, bound for Kure, and auxiliary aircraft transport MOGAMIGAWA MARU bound for Yokosuka.

14 April 1943:
Arrives at Yokosuka.

21 April 1943:
Departs Yokosuka and arrives at Yokohama later in the day.

E 22 April ~ 22 June 1943:
Undergoes hull, weapons and engine maintenance and repairs.

23 June 1943:
Departs Yokosuka for Truk escorting convoy No. 3623 also consisting of two unidentified merchant ships. The convoy sails at 10 knots.

3 July 1943:
Arrives at Truk.

9 July 1943:
Departs Truk escorting convoy No. 7091 also consisting of auxiliary water carrier NIPPO MARU. The convoy sails at 10 knots.

11 July 1943:
Arrives at Woleai.

15 July 1943:
Departs Woleai.

17 July 1943:
Arrives at Truk.

24 July 1943:
Departs Truk. Later that day, instructed to assist damaged auxiliary oiler TONAN MARU No. 3. [5]

27 July 1943:
Instructed to assist damaged auxiliary transport KINSEN MARU. Arrives in the area and tows the transport towards Truk. [6]

31 July 1943:
Arrives at Truk.

1 August 1943:
Departs Truk escorting convoy No. 5013 consisting of auxiliary transport SANSEI MARU (3266 gt) and IJN requisitioned cargo ships (B-AK) TATEBE and BOKUYO (MUTSUYO) MARUs. The convoy sails at 8 knots.

3 August 1943:
At some point, SANSEI MARU is detached and arrives at Ponape, Eastern Carolines.

7 August 1943:
Arrives at Kwajalein, Marshalls.

9 August 1943:
Departs Kwajalein escorting convoy No. 6093 consisting of auxiliary oiler HISHI MARU No. 2, IJN requisitioned cargo ship (B-AK) KENAN MARU and IJA transport KAIKO MARU. The convoy sails at 9 knots.

15 August 1943:
Arrives at Truk.

17 August 1943:
Departs Truk on trials and arrives back there later that day.

20 August 1943:
Departs Truk escorting convoy No. 7202 consisting of auxiliary transports SANSEI (3266 gt) and KEMBU (TATEBU) MARUs. The convoy sails at 10 knots.

27 August 1943:
Arrives at Palau.

6 September 1943:
Departs Palau on escort duties.

15 September 1943:
Arrives at Ulithi, Carolines.

18 September 1943:
Departs Ulithi on escort duties.

25 September 1943:
Arrives at Palau.

28 September 1943:
Scheduled to begin conversion to new military role under Navy’s secret instruction No. 4917-1.

1 October 1943:
Removed from the Navy’s list under instruction No. 2038 and registered again as an auxiliary transport, (Otsu) category attached to the Yokosuka Naval District with Yokosuka as home port under instruction No. 2041. Assigned to Fourth Fleet under secret instruction No. 96-8. Navy Lt (Reserve) Rizuka Chuichi is confirmed CO. [7]

That same day, departs Palau for Truk in convoy No. 8011 also consisting of IJN requisitioned tanker (B-AO) TENNAN MARU escorted by destroyer ASANAGI.

6 October 1943:
At 1200, arrives at Truk.

8 October 1943:
At 0530, departs Truk in convoy No. 4008 also consisting of auxiliary collier/oiler SANKO MARU, IJN requisitioned cargo ships (B-AK) TSUNESHIMA and CHIYO MARUs escorted submarine chaser CH-12 and cable layer escort HATSUSHIMA.

9 October 1943:
At 0515 CH-12 and HATSUSHIMA are detached.

E 10 October 1943:
Arrives at Saipan, Marianas.

11 October 1943:
Departs Saipan for Tateyama still in convoy No. 4008 joined by auxiliary transport MUKO MARU.

13 October 1943:
The convoy is joined by IJA transport TAIAN MARU and IJN requisitioned cargo ships (B-AK) MANJU and TATEBE MARUs, escorted by Kaibokan FUKUE and auxiliary subchaser TAKUNAN MARU No. 10.

18 October 1943:
The merged convoy arrives at Tateyama.

19 October 1943:
Departs Tateyama and arrives the same day at Yokosuka.

26 October 1943:
Departs Yokosuka in convoy No. 3026 consisting of auxiliary collier/oiler SOYO MARU and IJN requisitioned cargo ships (B-AK) AWA and SANKISAN MARUs also escorted by kaibokan FUKUE.

28 October 1943:
At 1850, SANKISAN MARU breaks down and is escorted by FUKUE to Chichijima. CHOAN MARU No. 2 GO continues to escort the convoy.

30 October 1943:
At 0130 SANKISAN MARU is due to arrive at Chichijima. FUKUE later rejoins the convoy.

6 November 1943:
At 1500, AWA MARU, destroyer OITE and CHOAN MARU No. 2 GO arrive at Truk SOYO MARU had already been detached.

8 November 1943:
Departs Truk in convoy No. 4108 also consisting of auxiliary storeship HOKO MARU escorted by destroyer OITE.

12 November 1943:
Arrives at Saipan. At 1538, departs for Yokosuka still in convoy No. 4108 also consisting of auxiliary transport HIYOSHI MARU, auxiliary storeship HOKO MARU escorted by destroyer OITE.

20 November 1943:
At 0700, arrives at Yokosuka.

23 November 1943:
Departs Yokosuka in convoy No. 3123 also consisting of auxiliary transports SHOKO, YAMAFUKU and TATSUTAGAWA MARUs, IJN requisitioned cargo ship (B-AK) SHIGANOURA MARU and IJA transport MANJU MARU escorted by destroyer OITE.

23-24 November 1943:
About 20nm NW of Hachijo-Jima, Izu Shoto. Night. LtCdr (later Rear Admiral) Merrill K. Clementson’s (USNA ’33) USS SNAPPER (SS-185) intercepts the convoy. At 0207, Clementson attacks but all torpedoes are avoided and the convoy resumes its course.

28 November 1943:
About 500nm NW of Guam. The convoy steaming in very rough weather, is intercepted by LtCdr Ian C. Eddy’s (USNA ’30) USS PARGO (SS-264) and by LtCdr (later Rear Admiral) Charles O. Triebel (USNA ’29) USS SNOOK. At 2200, Eddy attacks, but scores no hits. At 2206, Triebel fires a spread of torpedoes but again, no hits are scored. At 2208, Triebel attacks again but fail to score any hit. Both submarines continue to track the convoy.

At 2350, Triebel's USS SNOOK makes another attack and scores four hits on the lead ship of the convoy. Hit in the engine room and aft, at 2355, YAMAFUKU MARU sinks by the stern at 18-21N, 140-08E taking down 60 of her crew.

At some point, CHOAN MARU No. 2 GO is detached from convoy No. 3123 and joins convoy No. 3128 that departed Yokosuka earlier that same day, consisting of auxiliary transports NAGISAN, KENRYU and SHOHO MARUs, auxiliary storeship HARUNA MARU and IJA transport REIYO MARU escorted by kaibokan FUKUE.

29 November 1943:
About 15 nautical miles NW of Hachijo-Jima, Izu Shoto (Izu Islands), convoy No. 3128 is intercepted by LtCdr (later Rear Admiral) Merrill K. Clementson’s (USNA ‘33) USS SNAPPER (SS-185). At 0905, Clementson torpedoes and hits KENRYU MARU at 33-19N, 139-34E. She is set afire and settles down by the bows. Burning furiously, she is abandoned and sinks the next day at 33-16N, 139-35E. Four crewmen are KIA. KENRYU MARU is the only vessel sunk in that convoy.

1 December 1943:
Meets up with minesweepers W-17 and W-21 and auxiliary transport TATSUTAGAWA MARU, being the sole merchant survivor of convoy No. 3123. Arrives at Chichi-Jima, Ogasawara Gunto (Bonins).

3 December 1943:
Departs Chichi-Jima.

12 December 1943:
Arrives at Truk.

15 December 1943:
At 0800, departs Truk in convoy No. 4215 also consisting of auxiliary transport TATSUTAGAWA MARU, IJN requisitioned cargo ship (B-AK) TAIKOKU MARU, IJA transports GOSEI and SUMIYOSHI MARUs, IJN shared cargo ship (B/C-AK) TETSUYO MARU escorted by kaibokan AMAKUSA and auxiliary minelayer KINJO MARU.

16 December 1943:
Auxiliary minelayer KINJO MARU is detached from the convoy.

19 December 1943:
At 0700, convoy 3219 consisting of IJN requisitioned cargo ship (B-AK) DAITEN MARU escorted by kaibokan MANJU departs Yokosuka heading south. At some point the convoy is joined by CHOAN MARU No. 2 GO that then is detached for Yokosuka.

28 December 1943:
Arrives at Yokosuka.

31 December 1943:
At 0900, departs Yokosuka in convoy No. 3231 also consisting of auxiliary transport AKIBASAN MARU and IJN requisitioned cargo ships (B-AK) TATSUURA and KOKUYO MARUs escorted by kaibokan AMAKUSA.

1 January 1944:
Assigned to Eastern Carolines Guard Force.

12 January 1944:
Arrives at Truk.

19 January 1944:
Departs Truk in convoy No. 4119 consisting of IJN requisitioned cargo ship (B-AK) TATEBE (KEMBU) MARU, auxiliary collier/oiler MIKAGE MARU No. 18 and one unidentified ship escorted by kaibokan AMAKUSA, auxiliary gunboat HOKOKU MARU and auxiliary subchaser CHa-23.

31 January 1944:
Arrives at Yokosuka.

4 February 1944:
Arrives at Truk.

15 February 1944:
Navy Lt (Reserve) Kosaka Minezo is appointed CO.

12 April 1944:
Departs Yokohama and arrives at Tokyo later that day.

15 April 1944:
At 0600, departs Tokyo in “Higashi-Matsu” No. 6 consisting of IJA transports AWAJI, HAKUBA, KATSUKAWA, TAKAOKA, BATAVIA, AWA and HOKUSHIN MARUs and IJN requisitioned tanker (B-AO) NITCHO MARU bound for Saipan, CHOAN MARU No. 2 and IJA shared transport (A/C-AK) MIKAGE MARU No. 1 bound for Truk, civilian cargo ship C-AK) JOKUJA MARU, IJN requisitioned cargo ship (B-AK) BISAN MARU and IJA transport JINZAN MARU bound for Palau, IJN requisitioned cargo ship (B-AK) KAMISHIMA (SHINTO) MARU and IJA transport SHOZAN MARU bound for Woleai, civilian cargo ship C-AK) INARI MARU and IJA transport TONEGAWA MARU bound for Guam and IJA transports TATSUAKI and TAMAHOKO MARUs bound for Chichi-Jima.

The convoy is escorted by destroyers HOKAZE, YUNAGI and UZUKI, kaibokan MIYAKE and CD-6, minelayers SARUSHIMA, KYOSAI and YURISHIMA, minesweepers W-20 and W-28 and subchasers CH-10 and CH-12.

23 April 1944:
At 0500, arrives at Saipan.

29 April 1944:
Departs Saipan to meet up with “Higashi-Matsu” Convoy No. 7 (outbound) consisting of auxiliary transports ASAHISAN, TATSUHARU and MITAKESAN MARUs, IJN requisitioned cargo/transports OKINAWA, BINGO, YAMATAMA, MEIRYU, MOJI and MIHO MARUs bound for Saipan; auxiliary transport (ex-armed merchant cruiser) ASAKA MARU and landing ships T.128 and T.150 for Palau; auxiliary transport KOSHIN MARU and IJN requisitioned cargo/transport BOKUYO MARU for Yap and auxiliary transport TAITO MARU for Chichi-Jima. Escort is provided by kaibokan NOMI, CD-12, CD-18 and CD-22 and by subchasers CH-16 and CH-18.

30 April 1944:
Arrives at Guam, Marianas (renamed Omiya Island after its capture). At some point apparently departs Guam to meet up with “Higashi-Matsu” No. 7 convoy.

6 May 1944:
“Higashi-Matsu” No. 7 Convoy arrives at Saipan.

9 May 1944:
Departs Guam for Yap, Carolines in convoy also consisting of auxiliary transport IMIZU MARU, auxiliary collier/oiler MIKAGE MARU No. 18, IJN requisitioned cargo ship (B-AK) OKINAWA MARU and IJA transport MOJI MARU escorted by subchaser CH-30 and other unidentified small warship(s).

10 May 1944:
About 120 nautical miles SSW of Guam. LtCdr (later Rear Admiral) John S. Coye's (USNA ’33) USS SILVERSIDES (SS-236) attacks the convoy. At about 0435, Coye torpedoes and sinks CHOAN MARU No. 2 (41 crewmen and 12 passengers KIA), OKINAWA MARU (15 crewmen KIA) and MIKAGE MARU No. 18 (14 crewmen KIA) at 11-31N, 143-41E.

CH-30 and the other escort(s) depth-charge USS SILVERSIDES unsuccessfully. She evades and escapes. CH-30 rescues survivors. The remaining ships return to Guam.

10 July 1944:
Removed from the Navy’s list under instruction No. 855.


Authors' Notes :
[1] 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 subtracting 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.

[2] On 5 Mar ’42 about 2300 130 miles S of Truk, KAIJO MARU No. 2 GO was torpedoed and sunk by LtCdr Edward S. Hutchinson’s (USNA ’26) USS GRAMPUS (SS-207) with the loss of her Captain and 89 crew and passengers at 04-52N, 151-20E.

[3] On 16 May ’42, GOYO MARU was torpedoed and damaged S of Truk by LtCdr (later Cdr) Joseph H. Willingham’s (USNA ’26) USS TAUTOG (SS-199). To prevent her sinking, her Captain beached her on Royalist Reef.

[4] On 5 Aug ’42, BRASIL MARU was torpedoed and sunk about 130 nautical miles NW of Truk by LtCdr (later Rear Admiral) Henry C. Bruton’s (USNA ’26) USS GREENLING (SS-213) with the loss of 57 crewmen including Captain Ono, and an unknown number of passengers. About 200 survivors boarded four lifeboats. USS GREENLING submerges and picks up one survivor (a POW) from lifeboat No. 19.

[5] TONAN MARU No. 3 was torpedoed and damaged earlier that same day by LtCdr (later Rear Admiral) Lawrence R. Daspit’s (USNA ’27) USS TINOSA (SS-283).

[6] On 25 Jul ’43, KINSEN MARU was torpedoed and damaged by LtCdr Earl C. Hawk’s (USNA ’28) USS POMPON (SS-267) about 240 nautical miles N of Manus Island, Admiralties with the loss of 39 of her crew.

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

Thanks go to Gengoro S. Toda of Japan.

Gilbert Casse, Bob Hackett and Peter Cundall.

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