Japanese Auxiliary Netlayers

KYUSETSUMOKAN!

HOKAKUMOTEI!

(KOGI MARU – Berend van der Wal Collection)

IJN KOGI MARU:
Tabular Record of Movement

© 2022 Gilbert Casse, Berend van der Wal and Peter Cundall

1940:
Osaka. Laid down by Amagasaki Dock K.K. as a 857–tons cargo ship for Sanko Kisen K.K.
27 March 1940:
Launched and named KOGI MARU. [1]
14 August 1940:
Completed and registered at Amagasaki, with a Gross Registered Tonnage (GRT) of 857-tons and a Net Registered Tonnage (NRT) of 579-tons. Her call sign is JJZO. [1]
5 September 1941:
Requisitioned by the IJN.
20 September 1941:
Registered as an auxiliary netlayer attached to the Yokosuka Naval District under Cabinet Order No. 1093. Navy (Resv) Lt(jg). Adachi Mutsuo is appointed CO.
30 October 1941:
Conversion for military duty is completed.
31 October 1941:
Attached to the 66th Subchaser Division under instruction No. 1311. Attached to Vice Admiral Hosogaya Boshiro’s (36) Fifth Fleet, in Rear Admiral (later Vice Admiral) Abe Kasuke’s (39) 7th Base Force, 66th Subchaser Division based at Ominato.
1 December 1941:
Departs Yokosuka.
4 December 1941:
Arrives at Chichi Jima, Ogawasara Gunto (Bonins).
7 December 1941:
Departs Chichi Jima.
13 December 1943:
Arrives at Chichi Jima.
17 December 1941:
Departs Chichi Jima.
26 December 1941:
Arrives at Chichi Jima.
9 January 1942:
Departs Chichi Jima.
13 January 1942:
Arrives at Chichi Jima.
20 January 1942:
Departs Chichi Jima and returns there later this day.
24 January 1942:
Departs Chichi Jima.
25 January 1942:
Arrives at Chichi Jima.
31 January 1942:
Departs Chichi Jima.
1 February 1942:
Arrives at Chichi Jima.
4 February 1942:
Departs Chichi Jima and returns there later that day.
6 February 1942:
Departs Chichi Jima.
7 February 1942:
Arrives at Chichi Jima.
9 February 1942:
Departs Chichi Jima.
13 February 1942:
Arrives at Chichi Jima.
20 February 1942:
Lies alongside auxiliary gunboat YOSHIDA MARU. Replenishes boiler water. Departs Chichi Jima later this day.
27 February 1942:
Arrives at Chichi Jima.
28 February 1942:
Departs Chichi Jima.
1 March 1942:
Arrives at Chichi Jima.
4 March 1942:
Departs Chichi Jima.
14 March 1942:
Arrives at Chichi Jima.
11 March 1942:
Assigned to return to Chichi Jima after completion of current mission while maintening strict anti-submarine and anti-aircraft alerts under 7th Base Force instruction No. 665.
17 March 1942:
Departs Chichi Jima.
18 March 1942:
Arrives at Chichi Jima.
19 March 1942:
Departs Chichi Jima and returns there later this day.
20 March 1942:
Departs Chichi Jima and returns there later this day.
25 March 1942:
Departs Chichi Jima.
26 March 1942:
Arrives at Chichi Jima and departs there later that day.
27 March 1942:
Arrives at Chichi Jima.
1 April 1942:
Departs Chichi Jima.
2 April 1942:
Arrives at Chichi Jima.
7 April 1942:
Departs Chichi Jima.
8 April 1942:
Arrives at Chichi Jima.
9 April 1942:
Departs Chichi Jima.
10 April 1942:
Arrives at Chichi Jima and departs there later this day.
11 April 1942:
Arrives at Chichi Jima and departs there later that day.
12 April 1942:
Arrives at Chichi Jima.
13 April 1942:
Departs Chichi Jima.
14 April 1942:
Arrives at Chichi Jima.
16 April 1942:
Departs Chichi Jima.
17 April 1942:
Arrives at Chichi Jima.
19 April 1942:
Departs Chichi Jima.
22 April 1942:
Arrives at Chichi Jima.
23 April 1942:
Departs Chichi Jima.
24 April 1942:
Arrives at Chichi Jima.
26 April 1942:
Departs Chichi Jima.
27 April 1942:
Arrives at Chichi Jima.
7 May 1942:
Departs Chichi Jima.
8 May 1942:
Arrives at Chichi Jima.
9 May 1942:
Departs Chichi Jima.
10 May 1942:
Arrives at Chichi Jima.
14 May 1942:
Departs Chichi Jima.
17 May 1942:
Arrives at Uraga.
20 May 1942:
Enters drydock.
25 May 1942:
Undocked.
27 May 1942:
Departs Uraga and arrives at Yokosuka later this day.
3 June 1942:
Departs Yokosuka.
7 June 1942:
Arrives at Chichi Jima.
9 June 1942:
Departs Chichi Jima.
12 June 1942:
Arrives at Chichi Jima.
15 June 1942:
Detached from the 66th Subchaser Division under instruction No. 1048. Attached to the Chichi Jima Area Special Base Unit under instruction No. 1051.
18 June 1942:
Departs Chichi Jima.
19 June 1942:
Arrives at Chichi Jima.
26 June 1942:
Departs Chichi Jima.
30 June 1942:
Arrives at Chichi Jima.
3 July 1942:
Departs Chichi Jima and returns there later that day.
12 July 1942:
Departs Chichi Jima.
13 July 1942:
Arrives at Chichi Jima.
20 July 1942:
Departs Chichi Jima.
21 July 1942:
Arrives at Chichi Jima.
27 July 1942:
Departs Chichi Jima.
29 July 1942:
Arrives at Chichi Jima.
8 August 1942:
Departs Chichi Jima.
9 August 1942:
Arrives at Chichi Jima.
15 August 1942:
Departs Chichi Jima.
25 August 1942:
Arrives at Chichi Jima.
3 September 1942:
Departs Chichi Jima.
4 September 1942:
Arrives at Chichi Jima.
12 September 1942:
Departs Chichi Jima.
13 September 1942:
Arrives at Chichi Jima.
21 September 1942:
Departs Chichi Jima.
23 September 1942:
Arrives at Chichi Jima.
25 September 1942:
Rated as an Ogasawara (Bonins) Unit under Yokosuka Naval District order No. 126.
19 October 1942:
Departs Chichi Jima.
20 October 1942:
Arrives at Chichi Jima.
27 October 1942:
Departs Chichi Jima.
29 October 1942:
Arrives at Chichi Jima.
3 November 1942:
Departs Chichi Jima.
8 November 1942:
Arrives at Yokosuka.
4 December 1942:
Departs Yokosuka.
30 December 1942:
Arrives at Yokosuka.
5 January 1943:
Departs Yokosuka.
29 January 1943:
Arrives at Chichi Jima.
2 February 1943:
Departs Chichi Jima.
28 February 1943:
Arrives at Chichi Jima.
8 March 1943:
Departs Chichi Jima.
10 March 1943:
Arrives at Chichi Jima.
17 March 1943:
Departs Chichi Jima.
20 March 1943:
Arrives at Chichi Jima.
26 March 1943:
Departs Chichi Jima.
26 April 1943:
Arrives at Chichi Jima.
30 April 1943:
Departs Chichi Jima.
4 May 1943:
Arrives at Saipan, Marianas escorting auxiliary stores ship MANKO MARU.
6 May 1943:
Departs Saipan.
10 May April 1943:
Arrives at Chichi Jima.
22 May 1943:
Departs Chichi Jima.
5 June 1943:
Arrives at Chichi Jima.
13 June 1943:
Departs Chichi Jima.
23 June 1943:
Arrives at Chichi Jima.
1 July 1943:
Departs Chichi Jima.
4 July 1943:
Arrives at Chichi Jima.
8 July 1943:
Departs Chichi Jima.
1 August 1943:
Arrives at Chichi Jima.
12 August 1943:
Together with auxiliary minesweeper TOSHI MARU No. 5 (detached from convoy No. 3731) meets up with auxiliary gunboat EDO MARU to tow an oil tanker barge that had broken adrift from SANTO MARU in 22-20N, 143-46E, and which has been located by aerial search. EDO MARU is instructed to take the oil tanker barge under tow.
13 August 1943:
About 70 nautical miles ESE Iwo Jima, Bonins LtCdr Richard W. Peterson’s (USNA ‘31) USS SUNFISH (SS-281) sights a 3 ship convoy consisting of, according to Peterson, a tanker, a passenger/cargo ship and a CHIDORI type escort. Peterson fires 6 torpedoes at the tanker of which 3 hit. Peterson sees the tanker sinking by the stern. Then Peterson fires 4 torpedoes at the passenger/cargo ship. He hears 4 hits followed by breaking up noises. Only EDO MARU sank that day so she must have been the ship described as the tanker, which given her engines aft configuration is highly likely. She sinks at 24-04N, 142-21E with an unknown number of casualties. KOGI MARU, together with aircraft unsuccessfully hunt the submarine.
5 September 1943:
Departs Chichi Jima.
29 September 1943:
Arrives at Chichi Jima.
4 October 1943:
Departs Chichi Jima.
11 October 1943:
Arrives at Yokosuka.
16 October 1943:
Departs Yokosuka.
21 October 1943:
Arrives at Chichi Jima.
24 October 1943:
Departs Chichi Jima.
9 November 1943:
Arrives at Yokosuka.
3 December 1943:
Undocked.
7 January 1944:
Departs Yokosuka.
9 January 1944:
Probably from Tateyama, escorts with kaibokan FUKUE, convoy No. 3109 consisting of auxiliary transport KOSHIN MARU (6,530 GRT) and IJA transport GOSEI MARU. The ships sail at 9.5 knots.
11 January 1944:
Arrives at Chichi Jima.
15 January 1944:
At 1800, departs Chichi Jima with subchaser CH-51 escorting auxiliary transport (ex-gunboat) YOSHIDA MARU carrying 129 naval personnel, 116 civilian employees and 1,394-tons of military supplies.
18 January 1944:
LtCdr (later Rear Admiral) Reuben T. Whitaker's (USNA '34) USS FLASHER (SS-249) torpedoes and sinks YOSHIDA MARU at 23-46N, 151-30E. 76 passengers, eight crewmen and 15 gunners are KIA.
20 January 1944:
Departs Minami Torishima (Marcus Island).
6 February 1944:
Arrives at Chichi Jima.
March 1944:
Attached to Chichi Jima Area Defense, Subchaser Unit. Navy (Resv) Lt. Izumi Tsuyoshi is appointed CO.
1 March 1944:
Departs Chichi Jima on a test run and returns to base later this day.
11 March 1944:
Departs Chichi Jima escorting convoy ‘East Pine’ (Higashi-Matsu) No. 2. Escort ends at 30-20N.
17 March 1944:
Arrives at Chichi Jima. Assigned to an IJA unit transport mission under Ogasawara Unit instruction No. 8. At 0950, departs Chichi Jima with auxiliary minesweeper KEINAN MARU and probably unknown ‘T’ landing vessels or merchant ships.
18 March 1944:
At 0931, arrives at Iwo Jima.
20 March 1944:
IJA unit completes unloading operations. At 1500, departs Iwo Jima. 30 miles NE of Torishima. LtCdr (later Rear Admiral-Ret) Bafford E. Lewellen’s (USNA ‘31) USS POLLACK (SS-180) torpedoes and sinks auxiliary subchaser HAKUYO MARU, the sole ship in convoy No. 4318B, escorted by subchaser CH-44, at 30-53N, 140-42E. 28 crewmen are KIA.
21 March 1944:
Arrives at Chichi Jima. Assigned to a search and rescue mission for a crash landed aircraft between Chichi Jima and Nishino Jima, Bonins under Ogasawara Unit instruction No. 10. Departs Chichi Jima for crashed aircraft position and rescuing victims of the sunken auxiliary subchaser HAKUYO MARU.
23 March 1944:
Arrives at Chichi Jima.
24 March 1944:
Assigned to escort civilian passenger/cargo ship (C-APK) SHIBAZONO MARU from Chichi Jima to Iwo Jima and back under Ogasawara Unit wireless order No. 78.
25 March 1944:
Departs Chichi Jima escorting civilian passenger/cargo ship (C-APK) SHIBAZONO MARU.
26 March 1944:
At 2330, arrives at Iwo Jima.
28 March 1944:
Departs Iwo Jima.
April 1944:
Attached to Chichi Jima Area Defense, Ogasawara Subchaser Unit.
2 April 1944:
Arrives at Chichi Jima.
4 April 1944:
Receives wireless No. 26:
1 - Scheduled to escort convoy No. 4324 to Yokosuka on 4 April.
2 - 17th Mine Warfare Force CO commands escorts and convoy and ends escort near the 31st parallel N and then return.
3 - Auxiliary subchaser FUMI MARU and auxiliary netlayer KOGI MARU make a round voyage to Yokosuka for necessary repairs and then return to Tokyo Bay Unit Command.
Depending on the situation, return to convoy’s escort as appropriate.
Departs Chichi Jima with auxiliary gunboat NACHI MARU, auxiliary minesweepers KEINAN MARU, TOSHI MARU No. 8 and auxiliary subchaser FUMI MARU escorting convoy No. 4324 consisting of AWA and NISSHO MARUs, ASAHI MARU No. 2 and Fleet supply ship SOYA.
6 April 1944:
At 31N, auxiliary minesweeper KEINAN MARU detaches and returns to Chichi Jima. Arrives at Hachijo Jima, Izu Islands.
7 April 1944:
Departs Hachijo Jima.
8 April 1944:
Arrives at Yokosuka.
10 April 1944:
At Yokohama Asano Dock, undergoes hull and engine repairs.
15 April 1944:
Rated as an Ogasawara Area Defense Unit under Ogasawara Area Defense Unit wireless command No. 3.
12 May 1944:
Incorporated as a direct escort under wireless instruction No. 352.
14 May 1944:
Assigned to escort convoy No. 3516 between Yokohama and Chichi jima under wireless order No. 115.
16 May 1944:
Hull and engine repairs are completed. At 1200, departs Yokosuka with subchaser CH-52 and auxiliary netlayer KOA MARU No. 2 GO escorting convoy No. 3516 consisting of SEIGA and TOHO MARUs. At an unknown date SEIGA MARU drops out and KOA MARU No. 2 GO is detached .
20 May 1944:
At 0700, arrives at Chichi Jima. Incorporated as an Ogasawara Unit under wireless order No. 374.
21 May 1944:
Equipped with a Type 96 twin 25mm gun.
29 May 1944:
Assigned to return with emergency materials after completing convoy No. 4530-B escort under Ogasawara Unit instruction No. 55.
30 May 1944:
Departs Chichi Jima probably with minesweeper W-25 escorting convoy No 4530-B consisting of auxiliary transport KYUSHU MARU and an unknown number of merchant ships.
2 June 1944:
Arrives at Yokosuka.
7 June 1944:
Assigned to escort convoy No. 3609 under Ogasawara Unit wireless order No. 114. Departs Yokosuka and arrives at Yokohama later that day.
8 June 1944 :
Departs Yokohama with auxiliary minesweeper TOSHI MARU No. 5 escorting convoy No. 3609 consisting of auxiliary transports UNKAI MARU No. 10 and KYUSHU MARU, IJA transport YAEI MARU, IJN requisitioned cargo ship (B-AK) TATSUEI MARU and civilian passenger/cargo ship (C-AK) SHIBAZONO MARU (which joined from Hachijo Jima).
12 June 1944:
Arrives at Chichi Jima.
14 June 1944:
At 0700, departs Chichi-Jima with subchasers CH-16 and CH-18 and auxiliary minesweeper TOSHI MARU No. 5 escorting the ‘Yaei Maru’ convoy consisting of auxiliary transports UNKAI MARU No. 10 and KYUSHU MARU, IJA transport YAEI MARU and IJN requisitioned cargo ship (B-AK) TATSUEI MARU.
15 June 1944:
At 0615, at 29-20N, 140-35E FUKUEI MARU [likely error for TATSUEI MARU] is torpedoed but sustains no damage. CH-16 and CH-18 immediately start an anti- submarine sweep. At 0800, minesweeper W-25 joins escort. Later torpedo boat CHIDORI also joins.
16 June 1944:
At 0940, CH-16 and CH-18 stop anti-submarine sweeping and return to convoy. At 1430, TOSHI MARU No. 5 joins KYUSHU MARU and begins escorting her. In a raging storm from about 1640, UNKAI MARU No. 10, TATSUEI MARU, CH-16 and KOGI MARU separate from the convoy and steam together. At 1730, TOSHI MARU No. 5 joins YAEI MARU and begins escorting her.
18 June 1944:
Arrives at Nagaura and then Yokosuka.
19 June 1944:
Assigned to escort convoy No. 3622 and return to Chichi Jima under wireless order No. 449.
20 June 1944:
Wireless order No. 449 mission is confirmed under Ogasawara Unit wireless order No. 123.
21 June 1944:
Departs Yokosuka and arrives at Yokohama later this day.
22 June 1944:
At 0800, departs Yokohama with auxiliary minesweeper TOSHI MARU No. 5 escorting convoy No. 3622 consisting of auxiliary transport HYAKUFUKU MARU and civilian cargo ship (C-AK) NANYO MARU No. 1.
24 June 1944:
At 1700, arrives at Hachijo Jima.
27 June 1944:
At 1100, departs Hachijo Jima.
30 June 1944:
In the afternoon about 43 nautical miles NW of Muko-Jima, LtCdr (later Cdr) Clyde B. Stevens’ (USNA ’30) USS PLAICE (SS-390) running under the surface sights a convoy. At 1630, Stevens fires a spread of four torpedoes and scores two hits on HYAKUFUKU MARU. At 1635, the transport sinks at 28-20N, 141-23E with the loss of 16 crewmen. KOGI MARU carries out anti-submarine warfare and rescues survivors.
1 July 1944:
Arrives at Chichi Jima.
4 July 1944:
Departs Futami, Chichi Jima.
5 July 1944:
LtCdr (later Cdr) Clyde B. Stevens’ (USNA ’30) USS PLAICE (SS-390) attacks KOGI MARU. She is hit in the starboard bow and central engine room and subsequently sinks at 27-50N, 141-20E with the loss of three crewmen.
10 September 1944:
Removed from the Navy’s list under instruction No. 1067.

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.
Thanks go to Gengoro S. Toda of Japan.

- Gilbert Casse, Berend van der Wal and Peter Cundall.

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