Japanese Transports

ZATSUYOSEN!

(NIKKAI MARU, prewar)

IJN NIKKAI MARU:
Tabular Record of Movement

© 2011-2020 Gilbert Casse, Bob Hackett and Peter Cundall
Revision 3

10 November 1937:
Uraga. Laid down by Uraga Senkyo K.K. Kojo shipyard as a 2,562-ton cargo ship for Nissan Kisen K.K., Tokyo.
1 March 1938:
Launched and named NIKKAI MARU.
31 May 1938:
Completed and registered in Tokyo. Her gross registered tonnage and net registered tonnage are 2,562-tons and 1,439-tons respectively. Her call sign is JMGM. [1]
October 1938:
Arrives at Sasebo.
15 November 1940:
Requisitioned by the IJN as a transport (Ippan Choyosen). [2]
16 December 1940:
Registered in the IJN under internal order No. 980 and attached to the Yokosuka Naval District as an auxiliary gunboat. Capt. Aoki Setsuji is appointed Commanding Officer. Her home port is Yokosuka. Enters dock that same day at Asano Steel K.K. Shipyard, Tsurumi to start conversion.
25 December 1940:
Undocked. Capt. Aoki Setsuji’s appointment as Commanding Officer is confirmed.
27 December 1940:
Attached to the 13th Gunboat Squadron under Navy secret instruction No. 47.
14 January 1941:
The conversion is completed. [3]
15 January 1941:
Attached to the Combined Fleet Fourth Fleet.
1 February 1941:
Departs Shibaura.
E 1941:
Operates in the South Seas area (Japanese Mandated Islands).
10 July 1941:
Capt. Sakami Dehei is appointed Commanding Officer.
15 October 1941:
Attached to Combined Fleet, 4th Fleet, 4th Base Force in Captain Koyama Tokuhira's (38) 5th Gunboat Division, also consisting of auxiliary gunboats KEIJO and SEIKAI MARUs, based at Truk, Carolines. Navy (Resv) Capt. Okabe Takeshi is appointed Commanding Officer.
16 October 1941:
Truk. Engages in a gunfire drill.
11 November 1941:
Established as auxiliary gunboat No. 51.
1 December 1941:
Rated as a Truk Defense Unit Sea Surface Defense Unit. Assigned to defend Truk base perimeter and whereabouts. Replenishes fresh water.
2 December 1941:
Departs Ponape, Carolines, for Truk.
4 December 1941:
Arrives at Truk.
6 December 1941:
Loads general cargo (‘til 10 Dec).
8 December 1941:
Scheduled to load 12 Type 95 depth-charges under Navy secret instruction No. 6281. (Actual loading is in fact 24 DCs).
10 December 1941:
Departs Truk for Green Islands, Bismarcks.
12 December 1941:
Arrives at Green Islands. Starts unloading general cargo (‘til 14 Dec).
15 December 1941:
Departs Green Islands. That same day, engages in AA combat. Expends 56 12cm gun shells, 1,540 Type 93 13mm MGs bullets and 980 rifle bullets. A near-miss bomb deforms her portside hull, disconnects the antenna and breaks a gaff.
17 December 1941:
Arrives at Ponape.
19 December 1941:
Replenishes boiler water and coal (‘til 20 Dec).
20 December 1941:
Departs Ponape for Truk.
22 December 1941:
Arrives at Truk.
23 December 1941:
Replenishes boiler water and coal (‘til 24 Dec).
25 December 1941:
Departs Truk.
27 December 1941:
Conducts a random patrol NE of Truk.
30 December 1941:
Arrives at Truk.
31 December 1941:
Assigned to convoy protection under Navy instruction No 10.
5 January 1942:
Assigned to “R” operation in the third main body. Replenishes boiler water and coal; loads food rations (‘til 7 Jan).
7 January 1942:
At 1400 departs Truk for Guam, Marianas (renamed Omiya Island after its capture).
10 January 1942:
At 0700 arrives at Guam.
11 January 1942:
Departs Guam (Omiya Island) for comprehensive Navy and Army training.
12 January 1942:
Arrives back at Guam. Replenishes boiler water.
14 January 1942:
Departs Guam as part of Rabaul invasion force. Accompanied by auxiliary gunboat SEIKAI MARU, auxiliary minelayer MOGAMIGAWA MARU and auxiliary subchasers TOSHI MARU No. 5 and TAMA MARU No.8. They escort the third invasion echelon. At 1500 outside the port minelayer TSUGARU joins.
17 January 1942:
At 0300 the destroyers MUTSUKI and MOCHIZUKI detach. At 0940 the Sixth Destroyer Squadron and the Fourth Unit join west of Mereyon Island. At 1315 the destroyers MUTSUKI and MOCHIZUKI return. At 1515 the destroyer MOCHIZUKI detaches.
18 January 1942:
At 0430 the destroyer MUTSUKI detaches. At 0739 the auxiliary oiler KAIJO MARU No. 2 GO joins.
19 January 1942:
At 1700 the destroyer MUTSUKI returns.
20 January 1942:
At 1737 the destroyer YUNAGI detaches.
22 January 1942:
Arrives in waters near Rabaul. At 1000 the destroyer YUNAGI returns. At 1630 the convoy demarcates. Arrives outside Rabaul port later this day.
23 January 1942:
At 0020 landing of the third echelon starts. Rated as a main unit patrol unit under opreation R instruction No. 15. Patrols the entrance to Rabaul.
24 January 1942:
During the night stays in Rabaul harbor. Supplies 50-tons of coal to the auxiliary netlayer KOTOBUKI MARU No. 5. Patrols in Rabaul waters.
26 January 1942:
Sustains an air strike without incurring damage.
27 January 1942:
Sustains another air strike with no damage.
28 January 1942:
Sustains again an air strike without incurring damage.
30 January 1942:
Departs Rabaul. Patrols nearby.
31 January 1942:
Arrives at Rabaul.
1 February 1942:
Attached to Combined Fleet, 4th Fleet, 8th Base Force, “R” district forces No. 1, 1st Gunboat Division also consisting of auxiliary gunboats KEIJO and SEIKAI MARUs. Rated as the First Unit.
2 February 1942:
Dispatches fire damage parties to assist an abandoned Allied Merchant ship in flames on the east coast of the Bay [4]
4 February 1942:
Comes alongside auxiliary water carrier TATEYAMA MARU and replenishes boiler water. Departs later to patrol Rabaul’s waters.
11 February 1942:
Arrives at Rabaul.
13 February 1942:
Comes alongside auxiliary transport MUKO MARU and replenishes coal (‘til 14 Feb).
14 February 1942:
Auxiliary gunboat SEIKAI MARU’s CO temporarily assures command. Departs Rabaul for Green Island. Green Island appears to be the main source of bulk fresh water to supply the Rabaul garrison.
15 February 1942:
Arrives at Green Island area. Drifts outside the atoll waters and acts as a mothership.
16 February 1942:
Loads fresh water for Rabaul’s base.
20 February 1942:
Departs Green Island.
21 February 1942:
Patrols off Rabaul’s southern cape waters.
22 February 1942:
Arrives at Rabaul. Unloads fresh water and general cargo. Departs later that same day.
23 February 1942:
Conducts a search for a missing Aichi E13A1 “Jake” three-seat reconnaissance floatplane attached to auxiliary seaplane tender KIYOKAWA MARU’s air unit (‘til 24 Feb).
24 February 1942:
Arrives at Green Island area. Drifts outside the atoll. Protects the base’s waters.
28 February 1942:
Departs Green Island for Rabaul.
1 March 1942:
Arrives at Rabaul. Her previous CO is back to duty.
2 March 1942:
Sustains an airstrike without damage and fires back at the attacking aircraft with her Type 93 13mm MGs.
3 March 1942:
Undergoes cleaning of her holds.
4 March 1942:
Departs Rabaul. Patrols in the vicinity, conducts a random antisubmarine patrol and returns to Rabaul's waters.
7 March 1942:
Conducts a random antisubmarine patrol off Rabaul to protect light carrier SHOHO, anchored in the outer bay.
8 March 1942:
Arrives back at Rabaul. Comes alongside auxiliary water carrier TATEYAMA MARU and replenishes boiler water. Later that same day, departs Rabaul to patrol in the vicinity.
10 March 1942:
Arrives back at Rabaul. Departs later that day to conduct a search for a US seaplane shot down off Cape St. George.
11 March 1942:
Arrives back at Rabaul. Comes alongside auxiliary collier/oiler SANKO MARU and replenishes coal (‘til 12 Mar).
17 March 1942:
Remains attached to 8th Base Force, “R” district forces No. 1, 1st Gunboat Division.
18 March 1942:
Departs Rabaul to patrol the vicinity.
20 March 1942:
Arrives back at Rabaul. Comes alongside auxiliary repair ship MATSUE (SHOEI) MARU to undergo various repairs (completed 28 March).
23 March 1942:
Comes alongside auxiliary water carrier WAYO MARU. Replenishes boiler water. Undergoes cleaning to her holds (‘til 4 Apr).
28 March 1942:
Auxiliary gunboat KEIJO MARU’s CO temporarily assumes command.
31 March 1942:
Comes alongside and coals minesweeper W-20. Her previous CO returns to duty.
2 April 1942:
Comes alongside auxiliary water carrier TATEYAMA MARU and replenishes boiler water.
5 April 1942: Operation "MO" - The Invasions of Tulagi and Port Moresby:
No. 5 Gunboat Division’s KEIJO, SEIKAI and NIKKAI MARUs, CruDiv 18’s TATSUTA and TENRYU and seaplane carriers KAMIKAWA and KIYOKAWA MARUs are assigned to provide cover for Rear Admiral (Vice Admiral posthumously) Kajioka Sadamichi's (39) Port Moresby Attack Force's DesRon 6's light cruiser YUBARI, destroyers OITE, ASANAGI, MUTSUKI and YAYOI with a patrol boat and Rear Admiral (later Vice Admiral) Abe Koso's (40) (former CO of HIEI) Transport Force's 12 transports and minesweeper W-20.
6 April 1942:
Departs Rabaul to patrol in the vicinity.
7 April 1942:
Arrives back at Rabaul.
10 April 1942:
Attached to Combined Fleet, 4th Fleet, 8th Base Force.
13 April 1942:
Attached to the 8th Base Force's “R” district force No. 1, as the 2nd unit in 1st Gunboat Division.
14 April 1942:
Departs Rabaul to patrol in the vicinity.
15 April 1942:
Arrives back at Rabaul.
16 April 1942:
Departs Rabaul to patrol in the vicinity.
17 April 1942:
Arrives back at Rabaul. Comes alongside auxiliary collier SHIN YUBARI MARU and replenishes coal.
18 April 1942:
Departs Rabaul to patrol in the vicinity.
19 April 1942:
Attacked by aircraft without damage. Arrives back at Rabaul later that same day.
20 April 1942:
Departs Rabaul to patrol in the vicinity.
21 April 1942:
Arrives back at Rabaul. Departs later towing a water barge and arrives back that same day. Comes alongside auxiliary stores ship CHIYO MARU and loads raw food products.
22 April 1942:
A fresh water supply line is set up in Rabaul. Attached to No. 10 gunboat squadron under “R” secret instruction. Rated as a Marine Unit under R instruction No. 10.
23 April 1942:
Rated as an operation MO invasion unit under South Sea Unit Command instruction No. 13. Rated as a cover unit under Operation MO Invasion Unit Command instruction No. 1.
Sustains an airstrike without damage. Replenishes boiler water. Departs Massava, N of Rabaul and arrives back at Rabaul later that same day.
25 April 1942:
Comes alongside auxiliary water carrier WAYO MARU. Replenishes boiler water. Loads building materials for a future small seaplane base scheduled during “MO” forthcoming operation (completed 11 May). Auxiliary gunboat SEIKAI MARU’s CO temporarily assumes command.
26 April 1942:
Embarks 126 construction workers. Departs Rabaul for Shortland, Solomons with auxiliary gunboat SEIKAI MARU.
28 April 1942:
Arrives at Shortland. Begins landing building materials and construction workers to set up a seaplane base.
29 April 1942:
Departs Shortland to patrol in the vicinity and returns back later that same day.
30 April 1942:
Lands building materials and construction workers for the seaplane base.
5 May 1942:
Lights up searchlights to provide a beacon for the floatplanes’ take-offs and sea landings.
6 May 1942:
Embarks passengers. Departs Shortland for Tulagi, Solomons.
7 May 1942:
Receives eighth wireless order No. 16:
1 After completing the mission at Tulagi, auxiliary minesweepers HAGOROMO MARU and NOSHIRO MARU No. 2 GO, auxiliary oiler HOYO MARU, auxiliary gunboat NIKKAI MARU and if necessary auxiliary gunboat SHOEI MARU should quickly meet after landing the required Deboyne base cargo at point A, 7° 40'S, 153° 43'E.
2 Auxiliary gunboat KEYO MARU schould cooperate with the RZP invasion unit.
8 May 1942:
Arrives at Gavutu anchorage, Tulagi. Departs later that day for Rabaul.
10 May 1942:
Attacked by aircraft without damage.
11 May 1942:
At 2115 arrives at Rabaul
12 May 1942:
Departs Rabaul for Deboyne Island and from there escorts tanker HOYO MARU.
13 May 1942:
Her previous CO returns to duty.
15 May 1942:
Arrives Rabaul. Comes alongside auxiliary ammunition ship KOTOKU MARU and replenishes coal.
16 May 1942:
Departs Rabaul to patrol in the vicinity.
17 May 1942:
Arrives back at Rabaul. Comes alongside auxiliary water carrier WAYO MARU. Replenishes boiler water.
20 May 1942:
Departs Rabaul to patrol in the vicinity.
21 May 1942:
Arrives back at Rabaul. Departs later for a near drowning person search. Arrives back at Rabaul later that same day.
25 May 1942:
Departs Rabaul to patrol in the vicinity.
26 May 1942:
Arrives back at Rabaul.
27 May 1942:
Comes alongside auxiliary subchaser TAMA MARU No. 8 and replenishes her with boiler water.
29 May 1942:
Departs Rabaul. Calls at Duke of York Island, E of Rabaul and arrives back at Rabaul later that same day.
30 May 1942:
Loads general cargo.
31 May 1942:
Comes alongside auxiliary water carrier WAYO MARU. Replenishes boiler water.
1 June 1942:
Sustains an airstrike without damage. Auxiliary gunboat KEIJO MARU’s CO temporarily assures command.
3 June 1942:
Comes alongside auxiliary oiler/collier IWASHIRO MARU. Replenishes coal. Departs Rabaul that same day for Yokosuka.
7 June 1942:
Attached to 8th Base Force's “R” district force No. 1, 1st Gunboat Division.
16 June 1942:
Arrives at Yokosuka.
17 June 1942:
Unloads empty drums.
18 June 1942:
Enters Yokosuka Naval Shipyard’s 5th dock for engine repairs and fitting of an external degaussing cable.
24 June 1942:
Undocked.
9 July 1942:
The external degaussing cable fitting is completed.
11 July 1942:
Engine repairs are completed.
12 July 1942:
Replenishes coal.
13 July 1942:
Departs Yokosuka for speed and trimming trials. Arrives back at Yokosuka later that day.
14 July 1942:
Attached to 8th Base Force's 5th Gunboat Division also consisting of auxiliary gunboat SEIKAI MARU. Replenishes coal (‘til 15 July) and boiler water. Armor plates are fitted to her command bridge.
15 July 1942:
Loads rations and general cargo.
16 July 1942:
Assigned to defend Rabaul maritime perimeter and whereabouts under R’s instruction No. 24. Departs Yokosuka for Rabaul towing semi-submerged type water barge KOSHO No. 4008. 12 nms N of Sunosaki, patrol boat PB-2 joins as escort.
19 July 1942:
80 degrees and 12 nms off Muko Jima, Ogasawara Gunto (Bonins), PB-2 is detached. Later, 70 degrees and 10 nms off Muko Jima, minesweeper W-21 joins as escort.
21 July 1942:
Minesweeper W-21 is detached to Saipan for coal replenishment.
25 July 1942:
Minesweeper W-21 rejoins as escort.
26 July 1942:
The convoy arrives at Truk.
27 July 1942:
Replenishes coal (‘til 28 Jul).
31 July 1942:
Departs Truk, still towing water barge KOSHO No. 4008.
5 August 1942:
Arrives at Massava. Water barge KOSHO No. 4008 is delivered to Ports and Docks No. 8 unit. Replenishes boiler water and departs Massava, arriving at Rabaul later that same day.
6 August 1942:
Unloads general cargo.
7 August 1942:
Replenishes coal (‘til 8 Aug).
9 August 1942:
Departs Rabaul to patrol in the vicinity.
10 August 1942:
Arrives back at Rabaul. Unloads general cargo (‘til 12 Aug). Her previous CO returns to duty.
12 August 1942:
24 Type 95 depth-charges are replaced by new ones.
14 August 1942:
Departs Rabaul to patrol in the vicinity.
15 August 1942:
Arrives back at Rabaul.
16 August 1942:
Replenishes the water barge with fresh water. Undergoes a “deceptive full speed type” camouflage pattern coating to her bow and stern.
18 August 1942:
Departs Rabaul to patrol in the vicinity.
19 August 1942:
Arrives back at Rabaul. Comes alongside auxiliary water carrier WAYO MARU. Replenishes boiler water. Departs later that same day to patrol in the vicinity.
21 August 1942:
Arrives at Rabaul.
22 August 1942:
Departs Rabaul to patrol in the vicinity.
23 August 1942:
Arrives at Rabaul. Loads general cargo.
25 August 1942:
Departs Rabaul for Buka Island, Solomons.
26 August 1942:
Arrives at Buka. Unloads general cargo for the naval base’s personnel.
27 August 1942:
Embarks human remains. Departs Buka for Rabaul.
28 August 1942:
Arrives at Rabaul.
30 August 1942:
Departs Rabaul to patrol in the vicinity.
31 August 1942:
Arrives at Rabaul.
1 September 1942:
Replenishes coal.
2 September 1942:
Departs Rabaul to patrol in the vicinity.
3 September 1942:
Arrives back at Rabaul.
6 September 1942:
Departs Rabaul to patrol in the vicinity.
7 September 1942:
Arrives back at Rabaul.
8 September 1942:
Departs Rabaul to patrol in the vicinity. Conducts an antisubmarine random search and arrives back at Rabaul later that same day.
9 September 1942:
Comes alongside auxiliary transport MITAKESAN MARU for a coal replenishment.
10 September 1942:
Departs Rabaul to patrol in the vicinity.
11 September 1942:
Arrives back at Rabaul. Undergoes cleaning to her holds (‘til 19 Sep).
14 September 1942:
Tethers to rolling anchor due to a land-base fire in Rabaul’s harbor. Later anchors off Matupit coast.
15 September 1942:
Transfers to Rabaul’s harbor anchorage.
17 September 1942:
Sustains an airstrike without damage.
18 September 1942:
Comes alongside auxiliary stores ship TAKUNAN MARU. Replenishes boiler water.
21 September 1942:
Departs Rabaul to patrol in the vicinity.
22 September 1942:
Arrives back at Rabaul. Comes alongside auxiliary transport MITAKESAN MARU. Replenishes coal (‘til 23 Sep).
24 September 1942:
Sustains an airstrike without damage.
25 September 1942:
Detached from the 5th gunboat division under internal order No. 1781. Attached to the 8th Base Force at Rabaul.
E September 1942:
Departs Rabaul.
1 October 1942:
Arrives at Rabaul. Navy Captain (later Rear Admiral) Yokoyama Tokujiro (36) is appointed CO. The previous Captain disembarked 18 Aug. Captain Yokoyama is also assigned additional duty as CO of HAKKAI MARU.
9 October 1942:
Departs Rabaul for patrol mission.
10 October 1942:
Arrives back at Rabaul.
11 October 1942:
Departs Rabaul for a patrol mission.
13 October 1942:
Arrives at Rabaul.
14 October 1942:
Departs Rabaul for a patrol mission.
15 October 1942:
Arrives at Rabaul.
16 October 1942:
Departs Rabaul for a patrol mission.
17 October 1942:
Arrives at Rabaul.
18 October 1942:
Departs Rabaul for a patrol mission.
19 October 1942:
Arrives at Rabaul.
20 October 1942:
Departs Rabaul for a patrol mission.
21 October 1942:
Arrives at Rabaul.
22 October 1942:
Departs Rabaul for a patrol mission.
23 October 1942:
Arrives at Rabaul. Departs later that same day for a patrol mission.
24 October 1942:
Arrives at Rabaul.
30 October 1942:
Departs Rabaul for a patrol mission.
1 November 1942:
Arrives at Rabaul.
3 November 1942:
Departs Rabaul for a patrol mission.
4 November 1942:
Arrives at Rabaul.
6 November 1942:
Departs Rabaul for a patrol mission.
8 November 1942:
Arrives at Rabaul.
9 November 1942:
Departs Rabaul for a patrol mission.
10 November 1942:
Arrives at Rabaul.
12 November 1942:
Departs Rabaul for a patrol mission.
13 November 1942:
Arrives at Rabaul.
15 November 1942:
Departs Rabaul for a patrol mission.
18 November 1942:
Arrives at Rabaul.
22 November 1942:
Departs Rabaul for a patrol mission.
23 November 1942:
Arrives at Rabaul.
25 November 1942:
Departs Rabaul for a patrol mission.
26 November 1942:
Arrives at Rabaul.
28 November 1942:
Departs Rabaul for patrol mission.
29 November 1942:
Arrives at Rabaul.
1 December 1942:
Departs Rabaul for a patrol mission.
2 December 1942:
Arrives back at Rabaul.
4 December 1942:
Departs Rabaul for a patrol mission.
5 December 1942:
Arrives at Rabaul.
6 December 1942:
Departs Rabaul for a patrol mission.
10 December 1942:
Arrives at Rabaul.
11 December 1942:
Departs Rabaul for a patrol mission.
12 December 1942:
Arrives at Rabaul.
15 December 1942:
Departs Rabaul for a patrol mission.
16 December 1942:
Arrives at Rabaul.
18 December 1942:
Departs Rabaul for a patrol mission.
19 December 1942:
Arrives at Rabaul.
22 December 1942:
Departs Rabaul for a patrol mission.
23 December 1942:
Arrives back at Rabaul.
25 December 1942:
Departs Rabaul for a patrol mission.
26 December 1942:
Arrives at Rabaul.
28 December 1942:
Departs Rabaul for a patrol mission.
29 December 1942:
Arrives at Rabaul.
1 January 1943:
Departs Rabaul for a patrol mission and arrives back that same day.
3 January 1943:
Departs Rabaul for a patrol mission.
4 January 1943:
Arrives at Rabaul.
6 January 1943:
Departs Rabaul for a patrol mission.
7 January 1943:
Arrives back at Rabaul.
9 January 1943:
Departs Rabaul for a patrol mission.
10 January 1943:
Arrives back at Rabaul.
12 January 1943:
Departs Rabaul for a patrol mission.
13 January 1943:
Arrives at Rabaul.
15 January 1943:
Departs Rabaul for a patrol mission.
17 January 1943:
Arrives at Rabaul.
26 January 1943:
Departs Rabaul for a patrol mission.
27 January 1943:
Arrives at Rabaul.
28 January 1943:
Departs Rabaul for a patrol mission.
30 January 1943:
Arrives at Rabaul.
1 February 1943:
Departs Rabaul for a patrol mission.
2 February 1943:
Arrives at Rabaul.
4 February 1943:
Departs Rabaul for a patrol mission.
5 February 1943:
Arrives at Rabaul.
7 February 1943:
Departs Rabaul for a patrol mission.
8 February 1943:
Arrives at Rabaul.
10 February 1943:
Departs Rabaul for a patrol mission.
11 February 1943:
Arrives at Rabaul.
13 February 1943:
Departs Rabaul for a patrol mission.
14 February 1943:
Arrives at Rabaul.
16 February 1943:
Departs Rabaul for patrol mission.
17 February 1943:
Arrives at Rabaul.
19 February 1943:
Departs Rabaul for patrol mission.
20 February 1943:
Arrives back at Rabaul.
23 February 1943:
Departs Rabaul for a patrol mission.
24 February 1943:
Arrives at Rabaul.
25 February 1943:
Departs Rabaul for a patrol mission.
26 February 1943:
Arrives at Rabaul.
1 March 1943:
Departs Rabaul for a patrol mission.
2 March 1943:
Arrives at Rabaul.
4 March 1943:
Departs Rabaul for a patrol mission.
5 March 1943:
Arrives at Rabaul.
7 March 1943:
Departs Rabaul for a patrol mission.
8 March 1943:
Arrives at Rabaul.
10 March 1943:
Departs Rabaul for a patrol mission.
11 March 1943:
Arrives at Rabaul.
13 March 1943:
Departs Rabaul for a patrol mission.
14 March 1943:
Arrives at Rabaul.
17 March 1943:
Departs Rabaul for a patrol mission.
18 March 1943:
Arrives at Rabaul.
20 March 1943:
Departs Rabaul for a patrol mission.
21 March 1943:
Arrives at Rabaul.
23 March 1943:
Departs Rabaul for a patrol mission.
24 March 1943:
Arrives at Rabaul.
31 March 1943:
Departs Rabaul for a patrol mission.
4 April 1943:
Arrives at Rabaul.
6 April 1943:
Departs Rabaul for a patrol mission.
8 April 1943:
Arrives at Rabaul.
9 April 1943:
Departs Rabaul for a patrol mission.
10 April 1943:
Arrives at Rabaul.
12 April 1943:
Departs Rabaul for a patrol mission.
13 April 1943:
Arrives at Rabaul.
15 April 1943:
Departs Rabaul for a patrol mission.
16 April 1943:
Arrives at Rabaul.
18 April 1943:
Departs Rabaul for a patrol mission.
19 April 1943:
Arrives at Rabaul.
20 April 1943:
Departs Rabaul for a patrol mission.
21 April 1943:
Arrives at Rabaul.
23 April 1943:
Departs Rabaul for patrol mission.
24 April 1943:
Arrives at Rabaul.
26 April 1943:
Departs Rabaul for a patrol mission.
27 April 1943:
Arrives at Rabaul.
30 April 1943:
Departs Rabaul for a patrol mission.
1 May 1943:
Arrives at Rabaul.
2 May 1943:
Departs Rabaul for a patrol mission.
3 May 1943:
Arrives at Rabaul.
4 May 1943:
Departs Rabaul for a patrol mission.
5 May 1943:
Arrives at Rabaul.
7 May 1943:
Departs Rabaul for a patrol mission.
9 May 1943:
Arrives at Rabaul.
11 May 1943:
Departs Rabaul for a patrol mission.
13 May 1943:
Arrives at Rabaul.
15 May 1943:
Departs Rabaul for a patrol mission.
17 May 1943:
Arrives at Rabaul.
19 May 1943:
Departs Rabaul for a patrol mission.
21 May 1943:
Arrives at Rabaul.
24 May 1943:
Departs Rabaul for a patrol mission.
25 May 1943:
Arrives at Rabaul.
27 May 1943:
Departs Rabaul for a patrol mission.
29 May 1943:
Arrives at Rabaul.
30 May 1943:
Departs Rabaul for a patrol mission.
31 May 1943:
Arrives at Rabaul.
1 June 1943:
Departs Rabaul for a patrol mission.
2 June 1943:
Arrives at Rabaul.
4 June 1943:
Departs Rabaul for a patrol mission.
6 June 1943:
Arrives at Rabaul.
8 June 1943:
Departs Rabaul for a patrol mission.
10 June 1943:
Arrives at Rabaul.
20 June 1943:
Departs Rabaul for Yokosuka escorting a convoy consisting of unidentified ships.
25 June 1943:
Captain Yokoyama assumes full-time command of NIKKAI MARU.
11 July 1943:
Arrives at Yokosuka.
E July 1943:
Undergoes repairs probably at Yokosuka naval yard.
25 July 1943:
Departs Yokosuka for Truk escorting convoy No. 3725 consisting of TETSUYO MARU (as far as Chichi-Jima) and other unidentified ships.
E August 1943:
Arrives at Truk. Departs later for Rabaul.
16 August 1943:
Arrives at Rabaul.
27 August 1943:
Departs Rabaul arriving later that day at Kavieng, New Ireland.

16 September 1943:
Damaged by mine in Kavieng Harbor laid by Royal Australian Air Force PBY-5 the same time auxiliary gunboat SEIKAI MARU is mined and sunk.
1 October 1943:
Removed from the auxiliary gunboat list under internal order No. 2038. Registered in the IJN under internal order No. 2041 and attached to the Yokosuka Naval District as an auxiliary transport, (Ko) category. [5]

2 October 1943:
Detached from 8th Fleet, 8th Base Force under Navy secret order No. 730 (effective 1 Oct).
12 October 1943:
Comes alongside auxiliary transport NIKKO MARU and replenishes coal.
10 November 1943:
At 1400, departs Rabaul in convoy No. 2101 consisting only of NIKKAI MARU escorted by minesweeper W 28. Later that day stranded on Dewate Island.
12 November 1943:
Auxiliary submarine chaser CHa 23 and storeship HAYASAKI arrive and assist in refloating NIKKAI MARU.
13 November 1943:
Arrives back at Rabaul.
23 November 1943:
Departs Rabaul for Yokosuka in convoy also consisting of auxiliary water carrier WAYO MARU escorted by minesweeper W-26, subchaser CH-16, auxiliary subchaser CHa-20 and an unidentified auxiliary subchaser.
26 November 1943:
About 210 nms SSW of Puluwat Island (Endabi Shoto), Central Carolines. LtCdr (later Rear Admiral-Ret) Brooks J. Harral’s (USNA’32) USS RAY (SS-271) intercepts the convoy. At 1647, Harral fires six torpedoes and scores four hits on NIKKAI MARU at 04-12N, 148-26E. Mortally wounded, NIKKAI MARU breaks in three parts and sinks three minutes thereafter. Casualties are unknown, but Captain Yokoyama survives the sinking, and is promoted Rear Admiral on 1 May 1944.
5 January 1943:
Removed from the Navy List under internal order No. 54.

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] See Zatsuyosen home page for full explanation.
[3] NIKKAI MARU was fitted with three or four (estimated) 12-cm/45Cal 3rd Year Type guns, one twin 13-mm Type 93 MGs, one 7.7-mm single MG, rifles, pistols, three 75-cm searchlights, two depth-Charge stern racks with storage for 24 Type 95 DCs. One paravane, small minesweeping equipment, water disposal equipment.
[4] This probably refers to the Norwegian cargo ship HERSTEIN in nearby Matupi Harbour.
[5] 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 and Matt Jones for additional CO info.

-Gilbert Casse, Bob Hackett and Peter Cundall

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