Japanese Auxiliary Netlayers

KYUSETSUMOKAN!

HOKAKUMOTEI!
OSEI MARU, postwar (Berend van der Wal Collection)

IJN OSEI MARU:
Tabular Record of Movement

© 2024 Gilbert Casse, Berend van der Wal and Peter Cundall

E 1941:
Osaka. Laid down by Nakata Zosensho shipyard as a 641-tons cargo ship for Toko Shoji K.K.
June 1941:
Launched and named OSEI MARU.
. 10 October 1941:
Completed and registered at Amagasaki. Her gross registered (GRT) tonnage and net registered tonnage (NRT) respectively are 641-tons and 418-tons. Her call sign is JGVQ.
[1] October 1941:
Operated by Sanko Kisen K.K.
12 December 1941:
Osaka. Requisitioned by the IJN. Conversion for military duty begins at Nagata Zosensho shipyard.
20 December 1941:
Registered as an auxiliary netlayer attached to the Kure Naval District under Ordinance No. 1699.
23 December 1941:
Navy (Resv) Lt. Iseki Jingoro is appointed CO.
31 December 1941:
Conversion for military duty is completed. Attached to Saeki Base Defense Unit under Ordinance No. 1780. Attached to the Kure Naval District, Kure Defense Squadron, Saeki Base Defense Unit.
10 January 1942:
Departs Kure and arrives at Konoura later this day.
11 January 1942:
Departs Konoura and arrives at Saeki later that day.
14 January 1942:
Changes anchorage.
21 January 1942:
Departs Saeki on netlaying training. Arrives back at Saeki later this day.
22 January 1942:
Departs Saeki and arrives at Fukuura later that day.
23 January 1942:
Departs Fukuura.
25 January 1942:
Arrives at Fukuura.
26 January 1942:
Departs Fukuura.
27 January 1942:
Arrives at Sukumo.
29 January 1942:
Departs Sukumo.
30 January 1942:
Arrives at Saeki.
2 February 1942:
Changes anchorage.
5 February 1942:
Departs Saeki on training. Arrives back at Saeki later this day.
7 February 1942:
Departs Saeki on training. Arrives back at Saeki later that day.
16 February 1942:
Departs Saeki and arrives at Misaki later this day.
17 February 1942:
Departs Misaki and arrives at Motoura later this day.
18 February 1942:
Departs Motoura and arrives at Kure later that day.
28 February 1942:
Departs Kure and arrives at Saeki later this day.
1 March 1942:
Changes anchorage.
2 March 1942:
Departs Saeki.
3 March 1942:
Arrives at Sukumo.
5 March 1942:
Departs Sukumo and arrives at Fukuura later that day.
6 March 1942:
Departs Fukuura and arrives at Saeki later this day.
7 March 1942:
Departs Saeki.
8 March 1942:
Arrives at Shimizu.
9 March 1942:
Departs Shimizu and arrives at Kashiwajima later that day.
10 March 1942:
Departs Kashiwajima and arrives at Saeki later this day.
19 March 1942:
Departs Saeki and arrives back at Saeki later that day.
20 March 1942:
Departs Saeki and arrives back at Saeki later this day.
25 March 1942:
Departs Saeki.
26 March 1942:
Arrives at Saeki.
30 March 1942:
Departs Saeki on gunnery training and arrives back at Saeki later that day.
31 March 1942:
Departs Saeki and arrives back at Saeki later this day.
1 April 1942:
Departs Saeki and arrives back at Saeki later this day.
3 April 1942:
Departs Saeki
4 April 1942:
Arrives at Saeki.
5 April 1942:
Departs Saeki
6 April 1942:
Arrives at Saeki.
8 April 1942:
Departs Saeki
10 April 1942:
Arrives at Saeki.
12 April 1942:
Departs Saeki and arrives back at Saeki later this day.
13 April 1942:
At 1930, departs Saeki with patrol boat PB-2 escorting auxiliary cruiser BANGKOK MARU.
14 April 1942:
Attached to the Second Sweeping Force under Kure Defense Squadron wireless order No. 22.
15 April 1942:
Arrives at Sukumo.
17 April 1942:
Departs Sukumo.
18 April 1942:
Arrives at Saeki.
19 April 1942:
Assigned to compose the sweeping unit formation and conduct a mission according to Kure Defense Squadron Wireless No. 22 under Kure Defense Telephone No. 420. Departs Saeki that same day.
20 April 1942:
Arrives at Saeki.
21 April 1942:
Departs Saeki.
22 April 1942:
Arrives at Saeki.
23 April 1942:
Departs Saeki.
24 April 1942:
Arrives at Saeki.
26 April 1942:
Departs Saeki.
27 April 1942:
Arrives at Saeki.
29 April 1942:
Departs Saeki.
30 April 1942:
Arrives at Saeki.
2 May 1942:
Departs Saeki.
3 May 1942:
Arrives at Saeki.
5 May 1942:
Departs Saeki.
6 May 1942:
Arrives at Saeki.
8 May 1942:
Departs Saeki.
9 May 1942:
Arrives at Saeki.
11 May 1942:
Departs Saeki.
12 May 1942:
Arrives at Saeki.
14 May 1942:
Departs Saeki.
15 May 1942:
Arrives at Saeki.
19 May 1942:
Departs Saeki and arrives at Komame later that day.
20 May 1942:
Departs Komame.
21 May 1942:
Arrives at Saeki.
23 May 1942:
Departs Saeki and arrives back at Saeki later this day.
25 May 1942:
Departs Saeki.
27 May 1942:
Arrives at Nezumijima.
28 May 1942:
Departs Nezumijima.
29 May 1942:
Arrives at Saeki.
31 May 1942:
Departs Saeki.
1 June 1942:
Arrives at Saeki.
6 June 1942:
Departs Saeki.
7 June 1942:
Arrives at Saeki.
9 June 1942:
Departs Saeki.
10 June 1942:
Arrives at Saeki.
11 June 1942:
Departs Saeki on training and returns to base later that day.
12 June 1942:
Departs Saeki.
13 June 1942:
Arrives at Saeki.
14 June 1942:
Departs Saeki and arrives at Tsukumi later this day.
15 June 1942:
Departs Tsukumi and arrives at Kasado later that day.
July 1942:
Navy (Resv) Lt. Kawai Takamichi is appointed CO.
11 July 1942:
Departs Kasado on a test run and arrives back at Kasado later this day.
13 July 1942:
Departs Kasado and arrives at Saeki later that day.
16 July 1942:
Departs Saeki.
17 July 1942:
Arrives at Saeki.
19 July 1942:
Departs Saeki.
20 July 1942:
Arrives at Saeki.
22 July 1942:
Departs Saeki and arrives at Usuki later this day.
23 July 1942:
Departs Usuki and arrives back there later that day.
24 July 1942:
Departs Usuki and arrives back there later this day.
25 July 1942:
Departs Usuki.
26 July 1942:
Arrives at Saeki.
31 July 1942:
Departs Saeki on a test run and arrives back there later that day.
August 1942:
Navy (Resv) Suetake Keisuke is appointed CO.
1 August 1942:
Departs Saeki.
2 August 1942:
Arrives at Saeki.
4 August 1942:
Departs Saeki.
6 August 1942:
Arrives at Saeki.
8 August 1942:
Departs Saeki.
9 August 1942:
Arrives at Saeki.
11 August 1942:
Departs Saeki.
12 August 1942:
Arrives at Saeki.
13 August 1942:
Departs Saeki.
14 August 1942:
Arrives at Saeki.
16 August 1942:
Departs Saeki.
17 August 1942:
Arrives at Saeki.
19 August 1942:
Departs Saeki.
21 August 1942:
Arrives at Saeki.
22 August 1942:
Departs Saeki.
23 August 1942:
Arrives at Saeki.
25 August 1942:
Departs Saeki and arrives at Katagami later this day.
27 August 1942:
Departs Katagami.
28 August 1942:
Arrives at Nezumijima.
29 August 1942:
Departs Nezumijima and arrives at Saeki later that day.
31 August 1942:
Departs Saeki and arrives at Tsui later this day.
1 September 1942:
Departs Tsui and arrives at Saeki later that same day.
3 September 1942:
Departs Saeki.
4 September 1942:
Arrives at Saeki.
6 September 1942:
Departs Saeki.
7 September 1942:
Arrives at Saeki.
9 September 1942:
Departs Saeki.
10 September 1942:
Arrives at Saeki.
12 September 1942:
Departs Saeki.
13 September 1942:
Arrives at Kure.
15 September 1942:
Under command of Vice Admiral Mikawa Gunichi’s (38) Eighth Fleet.
23 September 1942:
Departs Kure.
October 1942:
Navy (Resv) Lt. Kishimoto Shinichi is appointed CO.
10 November 1942:
Departs Truk, Central Carolines on anti-submarine sweeping.
13 November 1942:
Arrives at Truk.
16 November 1942:
Departs Truk on anti-submarine sweeping.
18 November 1942:
Arrives at Truk.
20 November 1942:
Departs Truk on anti-submarine sweeping.
22 November 1942:
Arrives at Truk.
24 November 1942:
Departs Truk on anti-submarine sweeping.
25 November 1942:
Arrives at Truk.
26 November 1942:
Departs Truk on anti-submarine sweeping.
30 November 1942:
Arrives at Truk.
2 December 1942:
Departs Truk on anti-submarine sweeping.
5 December 1942:
Arrives at Truk.
8 December 1942:
Departs Truk on anti-submarine sweeping.
10 December 1942:
Arrives at Truk.
12 December 1942:
Departs Truk on anti-submarine sweeping.
15 December 1942:
Arrives at Truk.
17 December 1942:
Departs Truk on anti-submarine sweeping.
24 December 1942:
Arrives at Truk.
29 December 1942:
Attached to the 41st Naval Guard Unit under Ordinance No. 2432. Attached to Vice Admiral Samejima Tomoshige’s (37) Fourth Fleet, 4th Base Force, 41st Naval Guard Unit. Departs Truk on anti-submarine sweeping and returns to base that same day.
4 January 1943:
Departs Truk on patrol in assigned area.
6 January 1943:
Arrives at Truk.
8 January 1943:
Departs Truk on patrol in assigned area.
10 January 1943:
Engages in anti-submarine sweeping.
13 January 1943:
Arrives at Truk.
16 January 1943:
Departs Truk on patrol in assigned area and on anti-submarine sweeping.
21 January 1943:
Arrives at Truk.
24 January 1943:
Departs Truk on patrol in assigned area.
27 January 1943:
Arrives at Truk.
30 January 1943:
Departs Truk on patrol in assigned area.
February 1943:
Attached to the Truk Naval Force, Southern Force.
1 February 1943:
Arrives at Truk.
6 February 1943:
Departs Truk.
9 February 1943:
Arrives at Truk.
12 February 1943:
Departs Truk on patrol in assigned area.
15 February 1943:
Arrives at Truk.
18 February 1943:
Departs Truk on patrol in assigned area.
21 February 1943:
Arrives at Truk.
1 March 1943:
Departs Truk on patrol in assigned area.
4 March 1943:
Arrives at Truk.
7 March 1943:
Departs Truk on patrol in assigned area.
10 March 1943:
Arrives at Truk.
12 March 1943:
Departs Truk escorting auxiliary storeship CHIYO MARU.
16 March 1943:
Arrives at Truk.
20 March 1943:
Departs Truk.
21 March 1943:
Arrives at Endabi (Puluwat, , (now Poluwat), Central Carolines . Engages in TAKUNAN MARU rescue work.
22 March 1943:
Departs Endabi escorting a motor sailer convoy.
24 March 1943:
Arrives at Truk.
27 March 1943:
Departs Truk on patrol in assigned area.
30 March 1943:
Arrives at Truk.
April 1943:
Her ownership is changed to Sanko Kisen K.K.
2 April 1943:
Departs Truk on patrol in assigned area.
3 April 1943:
At 0505, heads in the direction of Endabi under Carolines Defense Forces wireless order No. 78.
5 April 1943:
Arrives at Truk.
9 April 1943:
Departs Truk on patrol in assigned area.
13 April 1943:
Arrives at Truk. Departs there on patrol in assigned area later that day.
14 April 1943:
Arrives at Truk.
17 April 1943:
Departs Truk on patrol in assigned area.
20 April 1943:
Arrives at Truk.
23 April 1943:
Departs Truk with destroyer ASANAGI escorting convoy No. 4426 consisting of auxiliary transport KAISHO MARU, NANKAI MARU (NB: possibly NANKAI MARU No. 2), auxiliary storeship SHINYO MARU and auxiliary cruiser NOSHIRO MARU.
E 27 April 1943:
Detaches from convoy and returns to Truk.
28 April 1943:
Arrives at Truk.
2 May 1943:
Departs Truk on patrol in assigned area. At 1715, engages in anti-submarine warfare. Executes a depth charge attack.
6 May 1943:
Arrives at Truk.
7 May 1943:
Departs Truk on patrol in assigned area.
10 May 1943:
Arrives at Truk.
15 May 1943:
Departs Truk on patrol in assigned area.
18 May 1943:
Arrives at Truk.
4 June 1943: Undergoes main engine test run.
5 June 1943:
Departs Truk on patrol in assigned area.
8 June 1943:
Arrives at Truk.
11 June 1943:
Departs Truk on patrol in assigned area. Sent to check if IJN transport HIDE MARU (torpedoed by USS SILVERSIDES on 10 June) is still afloat.
15 June 1943:
Arrives at Truk.
24 June 1943:
Enters 4th construction department floating dock.
29 June 1943:
Undocked.
July 1943:
Attached to Inland South Sea Forces, Caroline Defense Force. Attached to Truk Naval Patrol Force under Caroline Defense Force Command No. 22. Undergoes engine repairs.
1 July 1943:
Navy (Resv) Lt. Kishimoto Shinichi is appointed CO.
7 July 1943:
Departs Truk on patrol in assigned area.
14 July 1943:
Departs Truk on patrol in assigned area.
18 July 1943:
Arrives at Truk.
20 July 1943:
Departs Truk on patrol in assigned area.
21 July 1943:
Arrives at Truk.
24 July 1943:
Departs Truk on patrol in assigned area.
27 July 1943:
Arrives at Truk.
1 August 1943:
Remains attached to Truk Naval Patrol Force.
2 August 1943:
Ordered to return 2 sets of Type 14 laying nets under ordinance No. 2167.
4 August 1943:
Departs Truk on patrol, anti-submarine sweeping and mobile patrol in areas ‘NI’ and ‘K’.
8 August 1943:
Arrives at Truk. Departs there on patrol in assigned area later this day.
9 August 1943:
Arrives at Truk.
11 August 1943:
Departs Truk on patrol and anti-submarine sweeping in areas ‘I’ and ‘TA’.
15 August 1943:
Detached from the 41st Naval Guard Unit under ordinance No. 1665. Transferred as a special electric cable laying ship in the Kure Naval District under Ordinance No. 1666. Attached to Vice Admiral Kusaka Jinichi’s (37) Southeast Area Fleet. Navy (Resv) Lt. Kishimoto Shinichi is confirmed as CO.
Escorts inbound convoy No. 3805B consisting of auxiliary transports SHOEI MARU (3,099 GRT) and ASAHISAN MARU and auxiliary collier SHIN YUBARI MARU .
16 August 1943:
Arrives at Truk.
17 August 1943:
Undergoes repairs.
21 August 1943:
Departs Truk on an anti-submarine sweep at 50 nautical miles N Point ‘F’.
23 August 1943:
Conducts mobile patrol in areas ‘I’ and ‘TA’.
26 August 1943:
Engaged in anti-submarine sweeping.
27 August 1943:
Temporary halts at the North Passage.
28 August 1943:
Arrives at Truk.
2 September 1943:
Alongside repair ship AKASHI for repairs.
6 September 1943:
Casts off.
9 September 1943:
Installs one provisional mine detector.
11 September 1943:
Completes hanging Type K hydrophone repairs.
15 September 1943:
Departs Truk.
At 2030, LtCdr (later Rear Admiral) Roy M. Davenport's (USNA '33) USS HADDOCK (SS-231) sights OSEI MARU and an escort . Dives and tracks her. At 2310, at periscope depth sees that the escort has disappeared. Davenport fires four torpedoes. He observes two hits. One in the bow and the other in the stern. Explosions were seen but not heard therefore Davenport assumes the two torpedoes were duds. A fire appears to break out in OSEI MARU’s port side. She turns towards HADDOCK in order to ram her. A slight list to port is noted. Davenport fires two ‘down the throat’ torpedoes but they both miss target.
OSEI MARU reports being hit by a dud torpedo on the rear port side at 09-45N, 150-36E.
16 September 1943:
At 0016, with OSEI MARU still approaching, Davenport dives deep. OSEI MARU drops a single pattern of nine depth charges and keeps searching for HADDOCK. Davenport increases speed and leaves the site.
OSEI MARU reports dropping 28 Type 95 depth charges. Arrives at Truk later that day and moors alongside repair ship AKASHI for temporary repairs.
18 September 1943:
Casts off.
19 September 1943:
Departs Truk.
23 September 1943:
Arrives at Saipan, Marianas.
23 ~ 24 September 1943:
Loads fresh water and fuel.
24 September 1943:
Embarks 21 passengers.
25 September 1943:
Departs Saipan.
1 October 1943:
Arrives at Sukumo.
2 October 1943:
Departs Sukumo and arrives at Saeki later this day. The 21 passengers disembark.
3 October 1943:
Departs Saeki and arrives at Kure later that day.
6 October 1943:
Unloads ammunition.
12 October 1943:
Docks at Kure Naval Yard for permanent repairs and conversion to a cable layer.
15 October 1943:
A new Hachiko Type binocular telescope is fitted.
22 October 1943:
Ship bottom repairs are completed.
28 October 1943:
Anchor chain repairs are completed.
3 November 1943:
A stern signal light and a set of 3 Type 3 hydrophones are installed and wooden deck repairs are completed.
5 November 1943:
New engine warehouse and main accounting warehouse are completed and rear ship hold renovation is completed.
6 November 1943:
Troop room renovation is completed.
8 November 1943:
A new Type 93 13mm machine gun is fitted.
13 November 1943:
Conducts a hydrophone sea trial and center of gravity assessment.
15 November 1943:
One provisional mine detector and one set of hanging Type K hydrophone are returned. A new electric wire laying and hoisting equipment, new refrigerator and new wire storage are fitted.
18 November 1943:
A new Type four 1.5m rangefinder is fitted on the Type two base.
22 November 1943:
Removal of capture net lifting device is completed.
23 November 1943:
Repairs of two cutters are completed.
25 November 1943:
Removal of capture net stand is completed.
29 November ~ 3 December 1943:
Dispatched to outer port for electric wire laying trial.
4 December 1943:
Loads ammunition.
6 December 1943:
Loads and installs depth charge equipment.
9 December 1943:
Begins repainting of inner and outer hull.
10 December 1943:
Attached to Vice Admiral (later Admiral) Takasu Shiro’s (35) Southwest Area Fleet.
11 December 1943:
Repainting of inner and outer hull is completed.
20 December 1943:
Completes conversion to a cable layer and various formation and training.
15 February 1944:
Attached to Kita Base Force under Southwestern Unit Telegram No. 254.
3 March 1944:
Departs Kure and arrives at Shodoshima later this day.
4 March 1944:
Departs Shodoshima and arrives at Osaka later that day.
6 March 1944:
Lays an undersea cable.
7 March 1944:
Arrives at Kobe. Departs there escorting auxiliary oiler MANJU MARU later this day.
8 March 1944:
Arrives at Owase Bay.
9 March 1944:
Departs Owase Bay and arrives off Shinoshima.
10 March 1944:
Departs Shinoshima waters still escorting MANJU MARU.
11 March 1944:
Arrives at Yokosuka.
15 ~ 18 March 1944:
Lies alongside cable layer HARUSHIMA MARU and installs an undersea cable.
19 ~ 26 March 1944:
Prepares for laying and loads equipment.
27 March ~ 19 April 1944:
Conducts formation and training.
April 1944:
Attached to South Seas Unit under Souths Sea Unit Command No. 18.
25 April 1944:
Installs a new electric wire storage ventilation system.
26 April 1944:
One new motor boat is fitted.
2 May 1944:
Forecastle deck extension is completed.
3 May 1944:
Departs Yokosuka and arrives at Yokohama later that day.
5 May 1944:
One new Type 96 25mm single gun is fitted.
6 May 1944:
At 1430, departs Yokohama with auxiliary minesweepers SHOWA MARU No. 7 and SHOWA MARU No. 8, auxiliary subchasers CHa-54, CHa-56 and CHa-57 and auxiliary netlayer KISHIN MARU escorting convoy No. 3506 consisting of auxiliary storeships MAMIYA and TAKUNAN MARUs, auxiliary transport SHOSEI MARU, auxiliary gunboat UNKAI MARU No. 10 and IJA transport KAIKO MARU. At 2145, arrives at Tateyama.
8 May 1944:
At 0600, departs Tateyama. Auxiliary minesweeper SHOWA MARU No. 7 reinforces the convoy escort.
10 May 1944:
Due to mechanical failure, SHOWA MARU No. 7 straggles behind the convoy.
12 May 1944:
At 0630, arrives at Futami, Chichi-Jima, Ogasawara Gunto (Bonins).
14 May 1944:
Auxiliary transport TAITO MARU joins the convoy. At 1130, departs Chichi-Jima.
15 May 1944:
At some point, auxiliary gunboat UNKAI MARU No. 10 detaches.
18 May 1944:
SHOSEI MARU straggles and is left behind escorted by KISHIN MARU and CHa-67.
20 May 1944:
At 1030, arrives with the convoy at Saipan. Departs there later this day after receiving news of a potential airstrike from USN carrier-based aircraft, with destroyer MINATSUKI and auxiliary subchaser SHONAN MARU No. 3 escorting the ‘OSAKA MARU’ convoy consisting of IJA transport OSAKA MARU and auxiliary transport TAITO MARU.
24 May 1944:
NW Yap Island (Yappu-To), Carolines. Night-time. LtCdr (later Captain) Robert D. Risser’s (USNA ‘34) USS FLYING FISH (SS-229) intercepts the convoy. At 2217, Risser attacks OSAKA MARU but score no hits. During the night, USS FLYING FISH continues to track the convoy.
25 May 1944:
About 200 nms NW Yap, Risser attacks again the convoy. At 0920, USS FLYING FISH torpedoes hits OSAKA MARU starboard in hold No.1 and in the engine room, at 11-12N, 135-14E. OSAKA MARU goes dead in the water and is later abandoned by her crew, sinking at 1422, with the loss of 97 of her 824 passengers and 2,830 tons of cargo.
At 0921, TAITO MARU is also hit in the same attack. Her cargo of aviation gasoline erupts and she sinks at 0925, at the same position, taking with her 9 of her crew and 5 passengers, 5,300 aviation gasoline cans, 2,500m3 of arms and 500-tons of cement. OSEI MARU engages in rescuing survivors.
26 May 1944:
At 08-48N, 135-05E drops four Type 95 depth charges.
27 May 1944:
Arrives at Palau, Eastern Carolines.
1 June 1944:
Arrives at Koror Island, Palau.
6 June 1944:
Departs Arakabesang, Koror Island for Akarakora, Peleliu Island laying one line with four cores between the corners into the middle line.
8 June 1944:
Lays one undersea cable power between Peleliu Island and Gadobus Island.
9 ~ 11 June 1944:
At Malakal anchorage, prepares for laying.
12 June 1944:
At 0500 departs Palau escorting civilian passenger/cargo ship KINSHU MARU.
17 June 1944:
At 0940, SE of Cape San Augustin, Mindanao, Philippines LtCdr John C. Broach’s (USNA ’27) USS HAKE (SS-256) sights KINSHU MARU accompanied by three escorts. According to Broach these are two Type 13 class destroyer minelayers and one small unidentified gunboat (OSEI MARU). At 1104, Broach fires four torpedoes of which three hit and sink KINSHU MARU at 135° and 10 nautical miles of San Augustin Lighthouse with the loss of one crewman. From 1100 till 1215, escorts drop 38 depth charges. While USS HAKE leaves the site, she hears distant depth charges at 1343. At 1426, the small gunboat can still be seen through the periscope at a distance of about 10 miles and heard pinging. Further distant depth charges are heard at 1430 and 1603. At 1844, shortly before surfacing still hears pinging.
OSEI MARU drops 11 Type 95 depth charges, rescues victims and conducts anti-submarine sweeps.
18 June 1944:
Anti-submarine sweeping is ended. Arrives at Davao, Mindanao, Philippines later that day.
23 June 1944:
Begins formation and training.
6 July 1944:
15 Type 95 and 6 Type 2 depth charges are added.
14 July 1944:
Ends formation and training.
21 ~ 24 July 1944:
Lays an undersea cable between Davao and Samal Island, Mindanao, Philippines.
5 August 1944:
Minesweeper W-30 and auxiliary subchasers CHa-11 and KYO MARU No. 12 are assigned to escort fleet oiler TSURUMI, cargo ship BINGO MARU and auxiliary cable layer OSEI MARU on 5 Aug’ 44 from Davao to Zamboanga, Philippines under Southern Philippines Forces Telegram No 121.
At 0148, departs Davao for Zamboanga in the ‘TSURUMI convoy’ also consisting of fleet oiler TSURUMI and cargo ship BINGO MARU escorted by minesweeper W-30 and auxiliary subchasers CHa-11 and KYO MARU No. 12.
S Mindanao. At 1113, TSURUMI is attacked by LtCdr (later Captain) Edward F. Dissette’s (USNA ’34) USS CERO (SS-225) at 05-53N, 125-41E. In an underwater attack, Dissette fires six torpedoes and claims four hits. At 1130, TSURUMI capsizes and sinks in Davao Gulf with unknown casualties. W-30 may also have suffered damage. W-30 immediately attacks CERO with a depth charge. Then, escorts BINGO MARU to auxiliary subchaser KYO MARU No. 12 and orders her to escorts BINGO MARU back to Davao. OSEI MARU drops 7 depth charges. At 1137, W-30 orders auxiliary subchaser CHa-11 to rescue survivors. At 1250, W-30 orders OSEI MARU’s CO to command the convoy and head to Davao. She arrives there later this day.
On 11 August FRUMEL provided the following information based from an intercepted message from W-30:
"Minesweeper No. 30 reported oiler TSURUMI torpedoed in 5-53N, 125-41E at 1113 on 5 August and in danger of sinking."
W-30 herself was apparently not damaged.
6 August 1944:
Loads depth charges and 17-tons of heavy oil.
7 August 1944:
At 0853, departs Davao escorting the ‘BINGO MARU’ convoy consisting of BINGO MARU and auxiliary storeship SHINSEI MARU. Arrives at Malalag, Mindanao, Philippines later that day.
11 August 1944:
Departs Malalag in convoy Z-1105 consisting of OSEI MARU and SHINSEI MARU escorted by minesweeper W-30 and subchaser CH-3. At 1030, W-30 drops a depth charge. At 1230, W-30 drops six depth charges.
At 1800, SHINSEI MARU is detached. The convoy arrives at Glan, Mindanao later that evening. Auxiliary subchaser KYO MARU No. 12 and RYUKA (YANAGAWA) MARU join the convoy.
12 August 1944:
At 0354, departs Glan in convoy Z-1105 escorted by minesweeper W-3 and subchaser CH-3. At 0735, W-30 inspects a sailing ship. The convoy arrives at Malalag later this day
13 August 1944:
Departs Malalag in convoy Z-1105. At 1800, arrives at Zamboanga, Mindanao.
14 August 1944:
Departs Zamboanga and arrives at Basilan Island. Departs there later this same day.
15 August 1944:
Arrives at Zamboanga.
17 August 1944:
At 1800 departs Zamboanga in convoy C-172.
18 August 1944:
At 0600 arrives at Cebu, Philippines.
20 August 1944:
At 0800 departs Cebu in convoy M-202.
21 August 1944:
Arrives at Santa Cruz, Mindoro, Philippines.
22 August 1944:
Departs Santa Cruz and that evening arrives at Limbones Island, southern entrance to Manila Bay, Philippines.
23 August 1944:
Departs Limbones Island and arrives at Manila at 1100, later that day.
2 September 1944:
At 0300 departs Manila escorting auxiliary netlayer SHOEKI MARU.
4 September 1944:
At 1500 arrives at Cebu.
6 September 1944:
Lays an undersea cable between Cebu and Kawit Island, Philippines.
9 September 1944:
Departs Cebu in convoy M-103 also consisting of IJA transports MIKASA, SHICHIYO and TOYOHIME MARUs also escorted by patrol boat PB-103. Later this day, minelayer ENOSHIMA joins the convoy and starts escorting.
10 September 1944:
At 1050 arrives at Looc Bay, Masbate, Philippines.
12 September 1944:
At 1049 departs Looc Bay.
13 September 1944:
At 0430 arrives at Santa Cruz, Mindoro.
16 September 1944:
Departs Santa Cruz. At an unknown point, OSEI MARU detaches and heads towards Batangas, Luzon, Philippines. Arrives at Manila later that day.
18 ~ 19 September 1944:
Lays an undersea cable between Cavite, Manila Bay and Canacao, Manila Bay.
20 September 1944:
Departs Manila escorting convoy MATA-27A consisting of IJN requisitioned ships (B-AK) YUKIKAWA and AZUCHISAN MARUs, auxiliary transport JUZAN MARU and Manchukuo merchant ship IJA transport SHUN YUAN (called JUNGEN GO by the Japanese) also escorted by destroyers YUZUKI, UZUKI and AKIKAZE. Arrives at Corregidor North Channel, Manila Bay later this day.
21 September 1944:
At 0554 departs the Corregidor North Channel. From 0948 to 1048 the convoy is attacked by enemy aircraft but escapes damage. At 1800 AZUCHISAN MARU develops engine trouble and returns to Manila.
22 September 1944:
At 0508, in 15-28N 118-45E JUNGEN GO is torpedoed and sunk by USS LAPON. At 15-30N, 118-48E drops 7 Type 2 depth charges. Engages in anti-submarine sweeping and rescues survivors from the Manchukuo merchant ship IJA transport SHUN YUAN (called JUNGEN GO by the Japanese).
25 September 1944:
At 1555 AKIKAZE avoids three torpedoes fired by USS BECUNA. At 21-44N, 118-40E drops 5 Type 2 depth charges and 5 Type 95 depth charges.
26 September 1944:
At 1437 arrives at Takao, Formosa (now Kaoshiung, Taiwan).
27 September 1944:
At 1330 departs Takao escorting convoy TAMO-26 consisting of NIKKO, SEISHIN, CLYDE, HAKUSAN, MATSUURA, DAIJO, GASSAN, YOKO and BIYO MARUs and Army kidotei landing ship SS No.6 aldso escorted by kaibokan CD-3, CD-7, target ship HAKACHI and auxiliary gunboat CHOHAKUSAN MARU.
28 September 1944:
At 0205, kaibokan CD-1 joins the convoy and starts escorting. Arrives at Kirun, Formosa (now Keelung, Taiwan) later that day.
1 October 1944:
Departs Kirun escorting convoy TAMO-26. At 0900, kaibokan CD-1 arrives and begins escorting. Auxiliary gunboat CHOHAKUSAN MARU detaches and returns to Kirun later this day to repair damage to her main cooling water pipe.
3 October 1944:
Kaibokan CD-1 detaches and heads towards Nagasaki.
5 October 1944:
At 0600, detaches from the convoy.
6 October 1944:
At 0300, IJN general shared requisitioned tanker (B/C-AO) YOKO MARU seeks shelter at Azuchi-Oshima due to stormy weather. At 1130, completes main engine emergency repair and shelters at Fukuoka Bay until the winds calms down.
9 October 1944:
Arrives at Moji.
E 9 ~ 13 October 1944:
Departs Moji for Tokuyama.
13 October 1944:
Arrives at Kure.
20 October 1944:
Attached to the Kure Naval district. Navy (Resv) Lt. Aoyagi Ryoichiro is appointed CO.
28 October 1944:
Enters drydock.
14 November 1944:
Undocked.
17 November 1944:
Departs Kure for Osaka.
E 17 ~ 23 November 1944:
Loads electric wires.
23 November 1944:
Departs Osaka.
26 November 1944:
Lays an electric wire between Fukashima and Motoyama.
27 November 1944:
Arrives at Saeki.
4 December 1944:
Under command of Vice Admiral Sugiyama Rokuzo’s (38) Sasebo Naval District regarding the laying of undersea electric wires in the direction of the Nansei (Ryukyu) Islands under Osumi instruction No. 490.
6 December 1944:
Departs Saeki.
7 December 1944:
Arrives at Kure.
15 January 1945:
Departs Kure for Osaka and then Moji.
27 January 1945:
Arrives at Sasebo.
E 27 ~ 31 January 1945:
Departs Sasebo.
31 January 1945:
Arrives at Nishidomari, Nagasaki.
E 1 February ~ 20 February 1945:
Conducts wire work. Departs Nishidomari, Nagasaki for Osaka. Loads electric wires. Then, departs Osaka for Sasebo.
20 February 1945:
Arrives at Kagoshima.
26 February 1945:
Lays a telephone line between Ibusuki and Furue.
1 March 1945:
Departs Kagoshima in convoy ROKU-KITA-103 consisting of unidentified ships.
2 March 1945:
Arrives at Ushibuka.
5 March 1945:
Departs Ushibuka. Arrives at Kagoshima later that day.
6 March 1945:
Loads fresh water.
9 ~ 13 March 1945:
Lays an undersea cable between Korimoto, Kagoshima and Akamizu, Sakurajima.
15 March 1945:
Departs Kagoshima. Arrives at Furue later this day.
16 March 1945:
Departs Furue. Arrives at Yamakawa later that day.
18 March 1945:
Engages in anti-air combat.
19 March 1945:
Engages in anti-air combat.
21 March 1945:
Departs Yamakawa. Arrives at Kagoshima later this day.
22 March 1945:
Loads MG rounds.
23 March 1945:
Departs Kagoshima. Arrives at Yamakawa later that day.
25 March 1945:
Loads fresh water.
27 March 1945:
Lays an undersea cable between Ibusuki (Inu Yamazaki) and Yamakawa (Konpira hana).
28 ~ 29 March 1945:
Lays an undersea cable between Ibusuki (Inu Yamazaki) and Sata (Izashiki).
29 March 1945:
Engages in anti-air combat.
30 March 1945:
Departs Yamakawa.
31 March 1945:
Arrives at Nagasaki.
1 April 1945:
Attached to the Kure Defense Squadron.
7 April 1945:
Departs Nagasaki. Arrives at Sasebo later this day.
8 April 1945:
Loads MG rounds.
11 April 1945:
Departs Sasebo. Arrives at Hakata bay later that day.
12 April 1945:
Departs Hakata Bay. Arrives at Hesaki later this day.
13 April 1945:
Command of the Sasebo Naval District is ended under Osumi instruction No. 490 and Osumi instruction No. 517.
14 April 1945:
Rated as a Kure Chin Guard under Kure Chin Instruction No. 141032.
15 April 1945:
Departs Hesaki. Arrives at Kure later that day.
16 April 1945:
At the Kure Naval Yard. Repairs, reconstruction and new construction of the hull, weapons and engines begins.
20 April 1945:
Unloads gunpowder.
3 May 1945:
A new Type 3 detector and Type 3 detector base are installed.
6 May 1945:
Enters Kure No. 1 drydock.
8 May 1945:
A new direction Type 3 signal lamp is installed.
14 May 1945:
Undocked.
15 May 1945:
Loads food.
18 May 1945:
Loads coal.
20 May 1945:
A new Type 96 25mm twin gun is installed.
22 May 1945:
Two Type 96 25mm single guns, two Type 25mm single gun bases, a radio wave detector E27 receiver, a Type 3 radio wave detector and a Type 3 radio wave detector base are installed.
23 May 1945:
Loads ammunition.
24 May 1945:
A new Type 93 hydrophone for Type 2 small ships is installed. Conducts a compass correction and hydrophone trial. Repairs, reconstruction and new construction of the hull, weapons and engines are completed.
25 May 1945:
Departs Kure. Arrives at Ieshima later this day.
26 May 1945:
Departs Ieshima. Arrives at Osaka later that day.
27 ~ 29 May 1945:
Loads an undersea cable.
30 May 1945:
Departs Osaka. Arrives at Kobe Bay later this day.
31 May 1945:
Departs Kobe Bay. Arrives at Shimonoseki later that day.
2 June 1945:
Departs Shimonoseki. Arrives at Hagi later this day.
3 June 1945:
Departs Hagi. Arrives at Mishima later that day.
4 ~ 5 June 1945:
Lays an undersea cable between Mishima and Oi.
5 June 1945:
Departs Mishima. Arrives at Nagato Oi later this day.
6 June 1945:
Departs Nagato Oi. Arrives at Hagi later that day.
7 June 1945:
Departs Hagi. Arrives at Moji later this day. Attached to the Maizuru Naval District as a Base Unit.
10 June 1945:
Transships an undersea cable.
11 June 1945:
Loads fuel.
13 June 1945:
Departs Moji. Arrives at Yuya Bay later that day.
14 June 1945:
Departs Yuya Bay.
15 June 1945:
Arrives at Maizuru.
24 June 1945:
Rated as a Maizuru Naval District Unit, Maizuru Sea Surface Defense Unit.
21 July 1945:
Departs Maizuru.
22 July 1945:
Arrives at Niigata.
26 July 1945:
Departs Niigata.
27 July 1945:
Arrives at Ominato.
15 August 1945:
Ends of hostilities. Remains in service. Allotted SCAJAP No. P-020. Changed to a special cable laying ship.
21 August 1945:
Departs Ominato.
23 August 1945:
Arrives at Niigata.
1 September 1945:
Deregistered under instruction No. 041035. Decommissioned.
1946: Converted to a cable ship.
October 1949:
Sold to Toko Shoji, Amagasaki.
1954:
Converted to a cargo ship.
1956:
Transferred to Sanko Shosen, Amagasaki.
1958:
Sold to Kitakyushu Kisen, Osaka.
May 1959:
Hull is extended.
1960:
Sold to Kongo Kaiun K.K., Osaka. Renamed KONGO MARU.
1962:
Sold to Kongo Yuso K K. That same year, sold to Daisan Kaiun, Osaka. Renamed DAIYU MARU.
1967:
Sold to Kaihatsu Kaiun, Tokyo.
1979:
No longer listed in the Lloyd’s Register. However, apparently already scrapped before 1974.

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.

Back to the Netlayers Page