Japanese Auxiliary Netlayers

KYUSETSUMOKAN!

HOKAKUMOTEI!

(HIRO MARU in China, prewar – Peter Cundall collection)

IJN HIRO MARU:
Tabular Record of Movement

© 2021 Gilbert Casse, Berend van der Wal and Peter Cundall

1927:
Osaka. Laid down by Namura Zosen Tekkosho K.K. as a 549–tons passenger ship for Tsushima Shosen K.K.
May 1927:
Launched and named HIRO MARU.
1927:
Completed and registered at Fukuoka, with a Gross Registered Tonnage (GRT) of 549-tons and a Net Registered Tonnage (NRT) of 330-tons. Her call sign is JOJJ. [1]
20 June 1929:
Her owners are changed to Kitakyushu Shosen K.K.
1935:
Her owners are changed to Kyushu Yusen K.K.
19 February 1939:
Arrives at Wuhu, China. Departs there later this day.
21 February 1939:
Departs Wuhu and returns there later that day.
23 February 1939:
Departs Wuhu.
12 March 1939:
Arrives at Wuhu.
25 November 1941:
Requisitioned by the IJN.
Registered as an auxiliary netlayer attached to the Sasebo Naval district under instruction No. 1701.
31 December 1941:
Attached to the Kure Naval district under instruction No. 1779. Attached to Kure Local Defense Squadron, Saeki Base Defense Unit under instruction No. 1780.
1942:
Her GRT and NRT are changed respectively to 542-tons and 318-tons. [1]
15 January 1942:
Navy (Resv) Lt(jg) Takano Gunji is appointed CO.
12 February 1942:
Departs Saeki on training and returns to port later this day.
16 February 1942:
Departs Saeki on training and returns there later that day.
17 February 1942:
Departs Saeki on training and returns to port later this day.
21 February 1942:
Departs Saeki.
25 February 1942:
Arrives at Saeki.
27 February 1942:
Departs Saeki.
28 February 1942:
Arrives at Okinoshima.
1 March 1942:
Departs Okinoshima.
3 March 1942:
Arrives at Saeki.
4 March 1942:
Departs Saeki.
9 March 1942:
Arrives at Saeki.
11 March 1942:
Departs Saeki.
13 March 1942:
Arrives at Saeki.
14 March 1942:
Departs Saeki.
15 March 1942:
Arrives at Saeki.
17 March 1942:
Departs Saeki.
18 March 1942:
Arrives at Saeki.
19 March 1942:
Changes anchorage.
21 March 1942:
Departs Saeki.
22 March 1942:
Arrives at Saeki.
24 March 1942:
Departs Saeki.
27 March 1942:
Arrives at Saeki.
30 March 1942:
Departs Saeki on training and returns there later that day.
2 April 1942:
Departs Saeki towing a boat and returns to port later this day.
3 April 1942:
Changes anchorage.
6 April 1942:
Departs Saeki and arrives at Kure later that day.
9 April 1942:
Tethering.
10 June 1942:
Departs Kure.
11 June 1942:
Arrives at Saeki.
14 June 1942:
Departs Saeki.
15 June 1942:
Arrives at Saeki.
17 June 1942:
Departs Saeki.
18 June 1942:
Arrives at Saeki.
20 June 1942:
Departs Saeki.
21 June 1942:
Arrives at Saeki.
23 June 1942:
Departs Saeki.
24 June 1942:
Arrives at Saeki.
25 June 1942:
Departs Saeki and returns to port later this day.
26 June 1942:
Departs Saeki.
27 June 1942:
Arrives at Saeki.
29 June 1942:
Departs Saeki.
30 June 1942:
Arrives at Saeki.
1 July 1942:
Departs Saeki.
2 July 1942:
Arrives at Saeki.
5 July 1942:
Departs Saeki.
6 July 1942:
Arrives at Saeki.
8 July 1942:
Departs Saeki.
10 July 1942:
Arrives at Saeki.
11 July 1942:
Departs Saeki on training and returns there later that day.
12 July 1942:
Departs Saeki.
13 July 1942:
Arrives at Saeki.
15 July 1942:
Departs Saeki.
16 July 1942:
Arrives at Saeki.
18 July 1942:
Departs Saeki.
19 July 1942:
Arrives at Saeki.
20 July 1942:
Departs Saeki towing a boat.
21 July 1942:
Arrives at Saeki.
22 July 1942:
Departs Saeki and arrives at Usuki later this day.
23 July 1942:
Departs Usuki and returns there later that day.
24 July 1942:
Departs Usuki and returns to port later this day.
26 July 1942:
Departs Usuki and arrives at Saeki later that day.
27 July 1942:
Departs Saeki and returns there later this day.
31 July 1942:
Departs Saeki and arrives at Mizunoko later that day.
1 August 1942:
Departs Mizunoko and arrives at Saeki later this day.
3 August 1942:
Departs Saeki.
4 August 1942:
Arrives at Saeki.
5 august 1942:
Departs Saeki on training.
6 August 1942:
Arrives at Saeki.
7 August 1942:
Departs Saeki and returns there later that day.
9 August 1942:
Departs Saeki on a test run and returns to port later this day.
10 August 1942:
Departs Saeki.
11 August 1942:
Arrives at Saeki.
12 August 1942:
Departs Saeki.
13 August 1942:
Arrives at Saeki.
15 August 1942:
Departs Saeki.
16 August 1942:
Arrives at Saeki.
17 August 1942:
Departs Saeki and returns there later that day.
18 August 1942:
Departs Saeki.
20 August 1942:
Arrives at Saeki.
21 August 1942:
Departs Saeki.
22 August 1942:
Arrives at Saeki.
24 August 1942:
Departs Saeki.
25 August 1942:
Arrives at Saeki.
26 August 1942:
Departs Saeki on anchor change.
27 August 1942:
Arrives at Saeki.
28 August 1942:
Departs Saeki and returns there later that day.
30 August 1942:
Departs Saeki.
31 August 1942:
Arrives at Saeki.
2 September 1942:
Departs Saeki.
3 September 1942:
Arrives at Saeki.
5 September 1942:
Departs Saeki.
6 September 1942:
Arrives at Saeki.
8 September 1942:
Departs Saeki.
9 September 1942:
Arrives at Saeki.
11 September 1942:
Departs Saeki.
12 September 1942:
Arrives at Saeki.
14 September 1942:
Departs Saeki.
15 September 1942:
Arrives at Saeki.
17 September 1942:
Departs Saeki.
18 September 1942:
Arrives at Saeki.
20 September 1942:
Departs Saeki.
21 September 1942:
Arrives at Saeki.
23 September 1942:
Departs Saeki.
24 September 1942:
Arrives at Saeki.
26 September 1942:
Departs Saeki.
27 September 1942:
Arrives at Saeki.
29 September 1942:
Departs Saeki.
30 September 1942:
Arrives at Saeki.
12 October 1942:
Departs Saeki.
13 October 1942:
Arrives at Saeki.
14 October 1942:
Departs Saeki.
15 October 1942:
Arrives at Saeki.
17 October 1942:
Departs Saeki.
19 October 1942:
Arrives at Saeki.
20 October 1942:
Departs Saeki.
21 October 1942:
Arrives at Saeki.
22 October 1942:
Departs Saeki.
23 October 1942:
Arrives at Saeki.
24 October 1942:
Departs Saeki.
26 October 1942:
Arrives at Saeki.
27 October 1942:
Departs Saeki.
28 October 1942:
Arrives at Saeki.
29 October 1942:
Departs Saeki.
30 October 1942:
Arrives at Saeki.
31 October 1942:
Departs Saeki and arrives at Mizunoko later this day.
1 November 1942:
Departs Mizunoko and arrives at Saeki later that day.
3 November 1942:
Departs Saeki.
4 November 1942:
Arrives at Saeki.
6 November 1942:
Departs Saeki.
7 November 1942:
Arrives at Saeki.
8 November 1942:
Departs Saeki.
9 November 1942:
Arrives at Kitsuki.
10 November 1942:
Departs Kitsuki on gunnery practice and returns to port later this day.
11 November 1942:
Departs Kitsuki and arrives at Saeki later that day.
12 November 1942:
Departs Saeki.
13 November 1942:
Arrives at Saeki.
15 November 1942:
Departs Saeki.
16 November 1942:
Arrives at Saeki.
18 November 1942:
Departs Saeki.
20 November 1942:
Arrives at Saeki.
21 November 1942:
Departs Saeki.
23 November 1942:
Arrives at Saeki.
24 November 1942:
Departs Saeki.
25 November 1942:
Arrives at Saeki.
27 November 1942:
Departs Saeki.
28 November 1942:
Arrives at Saeki.
30 November 1942:
Departs Saeki and returns there later this day.
3 December 1942:
Departs Saeki.
4 December 1942:
Arrives at Saeki.
6 December 1942:
Departs Saeki.
7 December 1942:
Arrives at Saeki.
9 December 1942:
Departs Saeki.
10 December 1942:
Arrives at Saeki.
12 December 1942:
Departs Saeki.
13 December 1942:
Arrives at Saeki.
14 December 1942:
Departs Saeki.
15 December 1942:
Arrives at Saeki.
16 December 1942:
Departs Saeki.
18 December 1942:
Arrives at Saeki.
20 December 1942:
Receives Kure Defense instruction No. 37: Saeki Defense Base Unit Command: dispatch auxiliary netlayers KOA MARU No. 2 Go and HIRO MARU to Kure within 21 days. HIRO MARU shall engage in escort missions in accordance with Kure Naval District Command’s instructions.
21 December 1942:
Departs Saeki with auxiliary netlayer KOA MARU No. 2 Go and arrives at Kure later that day.
26 December 1942:
Departs Kure.
28 December 1942:
Arrives at Osaka.
January 1943:
Navy (Resv) Lt(jg) Makino Taro is appointed CO.
2 January 1943:
Departs Osaka on an escort mission.
4 January 1943:
Arrives at Kiiyura.
6 January 1943:
Departs Kiiyura.
8 January 1943:
Arrives at Tateyama.
10 January 1943:
Departs Tateyama escorting a convoy and returns to port later this day.
15 January 1943:
Departs Tateyama escorting a convoy.
18 January 1943:
Arrives at Osaka.
22 January 1943:
Departs Osaka.
23 January 1943:
Arrives at Yura.
25 January 1943:
Departs Yura escorting motor sailing vessels.
31 January 1943:
While towing a motor sailing vessel, the towline entangles with the propeller and disables navigation. Auxiliary netlayer MATSU MARU is sent to provide assistance. Arrives at Usami later that day.
Assigned to guide and direct second motor sailing vessel’s escort mission under Kure wireless order No. 9.
Assigned to escort under command of Yokosuka Chief a motor sailing convoy between Yokosuka and Saipan, Marianas under Kure Defense Command No. 28.
1 February 1943:
Departs Usami and arrives at Tateyama later this day.
2 February 1943:
Departs Tateyama and arrives at Taura, Yokosuka later that day.
8 February 1943:
Departs Taura and arrives at Uraga later this day.
13 February 1943:
Departs Uraga and arrives at Taura later that day.
17 February 1943:
Departs Taura on an escort mission and returns there later this day.
20 February 1943:
Departs Taura on an escort mission.
21 February 1943:
Arrives at Shimizu.
25 February 1943:
Departs Shimizu.
26 February 1943:
Arrives at Hachijo Jima, Ogasawara Gunto (Bonins).
28 February 1943:
Departs Hachijo Jima.
3 March 1943:
Arrives at Futami, Chichi-jima, Ogasawara Gunto.
10 March 1943:
Departs Futami with auxiliary netlayer SHOSEI MARU escorting a convoy consisting of IJA transport SHINKO MARU (3,119 GRT).
15 March 1943:
Arrives at Saipan, Marianas.
22 March 1943:
Departs Saipan escorting a convoy consisting of auxiliary transport KENYO MARU, auxiliary gunboat SEIKAI MARU acting as transport, and auxiliary stores ship MANKO MARU.
23 March 1943:
About 120 nms NNW of Saipan LtCdr (later Captain) Albert C. Burrows' (USNA ‘28) USS WHALE (SS-239) intercepts the convoy.
At 0304, Burrows torpedoes and obtains two hits on KENYO MARU, the first one under her bridge, the second at her stern, at 17-16N, 144-56E.
At 0310, while engaged in anti-submarine warfare drops 8 depth charges. Twenty minutes after being torpedoed, KENYO MARU sinks by the bow at 17-20N, 145-00E. 130 engineer passengers, 30 comfort women (IJA prostitutes) and four crewmen are KIA.
At 0435, heads to KENYO MARU sinking position to rescue survivors.
At 0559, search for survivors begins.
At 0925, search for survivors is ended.
24 March 1943:
Arrives at Saipan.
26 March 1943:
Order: As soon as SHOSEI MARU and auxiliary netlayer HIRO MARU are ready, they will return to Saeki from Saipan. On the way home in accordance with the local Commander, they shall be assigned as N coast escort. Plan and report actions under Kure Defense instruction no. 122.
30 March 1943:
Departs Saipan with auxiliary netlayer SHOSEI MARU, cable-layers HASHIMA and TATEISHI and for part way auxiliary subchaser KYO MARU No. 8 escorting damaged auxiliary aircraft transport KEIYO MARU.
8 April 1943:
Arrives at Taura.
16 April 1943:
Departs Taura.
20 April 1943:
Arrives at Saeki and ends escort mission.
25 April 1943:
Navy (Resv) Lt Okuno Fujio is appointed CO.
10 May 1943:
Departs Saeki and arrives at Kure later that day.
July 1943:
Navy (Resv) Lt(jg) Kunishi Setsuji is appointed CO.
12 July 1943:
Departs Kure on a test run and arrives at Honura later this day.
13 July 1943:
Departs Honura and arrives at Saeki later that day.
15 July 1943:
Departs Saeki.
16 July 1943:
Arrives at Saeki.
18 July 1943:
Departs Saeki.
19 July 1943:
Arrives at Saeki.
1 August 1943:
Departs Saeki and arrives at Kure later this day.
14 August 1943:
Departs Kure on training and returns there later that day.
18 August 1943:
Departs Kure.
19 August 1943:
Arrives at Kobe.
22 August 1943:
Departs Kobe.
23 August 1943:
Arrives at Kure.
25 August 1943:
Departs Kure.
26 August 1943:
Arrives at Moji.
29 August 1943:
Departs Moji and arrives at Hikoshima later this day.
30 August 1943:
Departs Hikoshima on an escort mission.
September 1943:
Navy (Resv) Lt Minagawa Tadashi is appointed CO.
4 September 1943:
Arrives at Shanghai, China.
10 September 1943:
Departs Shanghai.
14 September 1943:
Arrives at Kinmen (Quemoy) Island, China. Departs there on an escort mission later that day.
15 September 1943:
Arrives at Kinmen Island. Departs there on an escort mission and arrives at Amoy ((Hsia Men) now Xiamen), China later that same day.
17 September 1943:
Departs Amoy.
18 September 1943:
Arrives at Mako, Pescadores (Now Magong, Penghu islands, Taiwan).
21 September 1943:
Departs Mako.
26 September 1943:
Arrives at Manila, Philippines.
7 October 1943:
Departs Manila.
13 October 1943:
Arrives at Zamboanga, Mindanao, Philippines.
15 October 1943:
Departs Zamboanga.
19 October 1943:
Arrives at Menado, Celebes, Netherlands Indies (now Manado, Sulawesi, Indonesia).
20 October 1943:
Departs Menado on anti-submarine sweeping and returns there later this day.
22 October 1943:
Departs Menado on an escort mission.
25 October 1943:
Arrives at Ambon, Maluku Islands, Netherlands East Indies (now Indonesia).
26 October 1943:
Departs Ambon and returns there later that day.
28 October 1943:
Departs Ambon.
2 November 1943:
Arrives at Zamboanga. Departs there later for Kure.
5 November 1943:
Assigned to remove netlaying equipment and minesweeping equipment and to support transport missions under instruction No. 051742. That same day, armament is increased with one Type 93 13mm MG.
10 November 1943:
Attached to Vice Admiral Kusaka Jinichi’s (37) Southeastern Area Fleet under instruction No. 2381. Rated as a Southeastern Unit and as a RC area defense unit under NTB decree No. 140. That same day, departs Kure for Ambon.
27 November 1943:
Arrives at Saeki.
28 November 1943:
Departs Saeki and arrives at Kure later this day.
1 December 1943:
Departs Kure and arrives at Innoshima later that day. Reconstruction begins at Hitachi Zosen K.K., Innoshima shipyard.
4 December 1943:
Rated as a Western Escort Force, Escort Unit under New Guinea Corps wireless transmission No. 3.
31 December 1943:
Reconstruction is completed. Departs Innoshima and arrives at Kure later this day.
1 September 1943:
Loads 50-tons of gravel ballast.
4 September 1943:
Loads food and canteen products.
8 September 1943:
Departs Kure.
9 January 1944:
Arrives at Kobe.
13 January 1944:
Departs Kobe.
15 January 1944:
Arrives at Yokosuka.
17 January 1944:
Departs Yokosuka and arrives at Tateyama Bay later that day.
18 January 1944:
Departs Tateyama Bay with minesweeper W-23 and auxiliary netlayer KUDAMATSU MARU escorting convoy No. 3017.
19 January 1944:
Arrives at Mikurajima. Departs there and arrives at Hachijo Jima later that same day.
21 January 1944:
Departs Hachijo Jima.
24 January 1944:
Arrives at Chichi-Jima.
27 January 1944:
Departs Chichi- Jima.
31 January 1944:
At 2105, Cdr Charles F. Brindupke's (USNA '32) USS TULLIBEE (SS-284) fires three torpedoes at HIRO MARU of which one hits the port engine room. HIRO MARU sinks after about a minute at 15-21N, 145-31E and about 16 nautical miles NW Garapan, Saipan. 55 passengers and one crewman are killed.
10 June 1944:
Removed from the Navy’s list under instruction No. 752.

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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