ZATSUYOSEN!
(MUKO MARU prewar)
IJN MUKO MARU:
Tabular Record of Movement
© 2011-2016 Gilbert Casse, Bob Hackett and Peter Cundall
Revision 5
31 March 1937:
Sakurajima, Osaka. Laid down by Tekkosho Honsha Kojo K.K. shipyard as a 4,862-ton cargo ship for Taihei Kisen K.K., a division of Yamashita Kisen K. K., Kobe.
27 July 1937:
Launched and named MUKO MARU.
20 October 1937:
Completed and registered in Kobe. Her registered beam is 52.5’.
E 1937-1940:
Placed on Taihei Kisen’s Kobe ~ New Zealand commercial service.
10 April 1938:
Ran ashore off Kandoshi Zaki, but refloated and under repairs for about one month.
16 June 1940:
Her registered beam is changed to 54.5’.
1 December 1940:
Requisitioned by the IJN.
16 December 1940:
Registered in the IJN as an auxiliary transport, (Ko) category under internal order No. 980 and attached to the Yokosuka Naval District. Her home port is Yokosuka Naval Base. [1]
10 May 1941:
Captain (Rear Admiral, posthumously) Abe Koun (41) (ex-XO of repair ship AKASHI) is appointed Supervisor. Her civilian Captain resigns on 19 Sep ’41.
25 May 1941:
Departs Yokosuka and operates in southern China waters.
5 July 1941:
Arrives at Yokosuka.
E July 1941:
Departs Yokosuka at an unknown date.
E August 1941:
Arrives at Shibaura, Tokyo at an unknown date.
22 August 1941:
Departs Shibaura and South Seas area.
20 September 1941:
Arrives at Yokosuka. Captain Abe disembarks. An unknown IJN Captain is appointed supervisor and embarks. Departs Yokosuka and arrives at Shibaura at an unknown date.
25 September 1941:
Departs Shibaura and operates in South Seas area.
10 November 1941:
Arrives at Yokosuka. Begins conversion at Yokusuka Naval Yard to her military auxiliary transport role.
26 November 1941:
The conversion is completed.
3 December 1941:
Departs Yokosuka.
29 December 1941:
Arrives at Yokosuka.
18 January 1942:
Departs Yokosuka, initially escorted by auxiliary gunboat KASAGI MARU.
E February 1942:
Arrives at Rabaul at an unknown date.
11 February 1942:
Comes alongside auxiliary gunboat SEIKAI MARU and transfers some coal until 12 February.
13 February 1942:
Comes alongside auxiliary gunboat NIKKAI MARU and transfers some coal until 14 February.
22 February 1942:
Comes alongside auxiliary gunboat KEIJO MARU and transfers some coal until 24 February.
24 February 1942:
Comes alongside SEIKAI MARU again and transfers more coal.
E March 1942:
Departs Rabaul at an unknown date.
30 March 1942:
Arrives at Yokosuka.
23 April 1942:
Departs Yokosuka.
3 May 1942:
Arrives at Yokosuka. Later departs and arrives at Yokohama at an unknown date.
12 May 1942:
Departs Yokohama escorted by survey vessel KOMAHASHI enroute to Rabaul. Later that day, KOMAHASHI is detached and escorts inbound cargo ship TOYO MARU No. 2.
21 June 1942:
Arrives at Yokosuka.
4 July 1942:
Departs Yokosuka.
25 July 1942:
Departs Roi.
26 July 1942:
Arrives at Wotje.
29 July 1942:
Departs Wotje.
31 July 1942:
Departs Taroa.
28 August 1942:
Arrives at Yokosuka. Later departs and arrives at Yokohama at an unknown date.
4 September 1942:
Departs Yokohama.
24 September 1942:
Departs Palau in a convoy also consisting of water tanker GORYU MARU with unknown escort.
29 September 1942:
Off Ulul Atoll auxiliary gunboat CHOUN MARU joins the convoy.
30 September 1942:
Arrives at Truk.
6 October 1942:
Departs Truk in convoy also consisting of IJN auxiliary water tanker TATEYAMA MARU escorted by auxiliary gunboat CHOUN MARU.
9 October 1942:
Arrives at Saipan. CHOUN MARU meets up with INARI MARU and begins escorting this ship.
4 November 1942:
Arrives at Yokosuka.
5 December 1942:
MUKO MARU shifts category from Zatsuyosen (Ko) to Zatsuyosen (Otsu) [1].
12 December 1942:
Departs Yokosuka for Saipan, Marianas in a convoy also consisting of YAMASHIRO MARU.
18 December 1942:
Arrives at Saipan. Departs Saipan alone and arrives the same day at Tinian, Marianas.
20 December 1942:
Departs Tinian and arrives the same day at Saipan.
22 December 1942:
Departs Saipan for Truk, Carolines in a convoy also consisting of YAMASHIRO MARU.
25 December 1942:
Minesweeper W-8 joins the convoy at 07-55N, 153-07E. The convoy arrives at Truk later that day.
4 January 1943:
Departs Truk for Palau.
9 January 1943:
Arrives at Palau, Carolines.
12 January 1943:
Departs Palau for Fais (Fuhaesu), Carolines.
14 January 1943:
Arrives at Fais.
15 January 1943:
Departs Fais.
2 February 1943:
Arrives at Yokosuka.
12 February 1943:
Departs Yokosuka in a convoy with destroyer MINEGUMO as escort.
22 February 1943:
Arrives at Truk, Carolines.
24 February 1943:
Departs Truk in a convoy escorted by cable layer escorts HASHIMA and TATEISHI.
27 February 1943:
Arrives at Rabaul.
30 March 1943:
Departs Rabaul, New Britain in a convoy also consisting of FUKUYAMA MARU and possibly others with unknown escort.
3 April 1943:
Arrives at Truk.
13 April 1943:
Departs Truk in a convoy also consisting of FUKUYAMA MARU and possibly others with unknown escort.
18 April 1943:
Arrives at Palau.
20 April 1943:
Departs Palau.
22 April 1943:
Arrives at Fais.
27 April 1943:
Departs Fais.
29 April 1943:
Arrives at Palau.
2 May 1943:
Departs Palau for Kobe in convoy P-502 also consisting of MITAKESAN, MYOKO, NISSHO, SHICHISEI and MYOGI MARUs, escorted by patrol boat PB-46.
9 May 1943:
About noon, auxiliary minesweeper TAKUNAN MARU No. 3 joins the escort.
10 May 1943:
Off Saeki the convoy is dissolved.
11 May 1943:
MUKO MARU arrives at Kobe and departs the same day for Yokosuka.
13 May 1943:
Arrives at Yokosuka and departs for Yokohama where she arrives later in the day.
19 May 1943:
Departs Yokohama and arrives the same day at Yokosuka.
26 May 1943:
Departs Yokosuka for Truk in convoy No. 3526A consisting of unidentified ships.
4 June 1943:
Arrives at Truk.
8 June 1943:
Departs Truk for Rabaul.
12 June 1943:
Arrives at Rabaul.
4 July 1943:
Departs Rabaul for Palau in a convoy with possibly others with unknown escort.
10 July 1943:
Arrives at Palau.
25 July 1943:
Departs Palau for Kobe in convoy FU-506 also consisting of MATSUE, HIBI, KOYU, YURI, and KOFUKU MARUs escorted by torpedo boat HATO and patrol boat PB-46.
E 26 July 1943:
HATO is detached from the convoy.
E 1 August 1943:
Minelayer YURIJIMA and auxiliary minesweeper TAKUNAN MARU No. 3 join convoy FU-506 at 28-25N, 136-40E to provide additional escort.
3 August 1943:
MUKO MARU arrives at Kobe.
4 August 1943:
Departs Kobe and arrives the same day at Wakaura, Wakayama Prefecture.
5 August 1943:
Departs Wakaura for Yokosuka.
7 August 1943:
Arrives at Yokosuka.
15 August 1943:
Departs Yokosuka for Truk in a convoy also consisting of KYOWA, SAN FRANCISCO and SHOUN MARUs and possibly others with unknown escort.
25 August 1943:
Arrives at Truk.
27 August 1943:
Departs Truk for Kwajalein, Marshalls in convoy No. 5872 also consisting of IJN requisitioned cargo ship (B-AK) SHIGANOURA MARU and auxiliary transport CHIHAYA (ex-Dutch TJISAROEA) MARU escorted by torpedo boat HIYODORI and auxiliary subchaser CHa-25.
1 September 1943:
Arrives at Kwajalein.
4 September 1943:
Departs Kwajalein and arrives the same day at Roi-Namur, Marshalls.
7 September 1943:
Departs Roi-Namur and arrives the same day back at Kwajalein.
18 September 1943:
Departs Kwajalein for Truk in convoy No. 6188 also consisting of KEMBU, CHIHAYA, MANJU, MINATO, TSUNESHIMA, SHIGANOURA and KENRYU MARUs escorted by torpedo boat HIYODORI, subchasers CH-28 and CH-31, auxiliary subchasers KYO MARU No. 6 and TAKUNAN MARU No. 10.
25 September 1943:
At 1200. the convoy arrives at Truk.
26 September 1943:
At 1000, departs Truk for Saipan in convoy No. 4926 also consisting of auxiliary fleet replenishment vessel SANTO MARU, auxiliary transport KENRYU MARU and Navy requisitioned TSUNESHIMA MARU escorted by destroyers IKAZUCHI and YUZUKI. [2].
29 September 1943:
About 10 nms WNW Saipan. At 1000, LtCdr (later Rear Admiral) William S. Post’s (USNA '30) USS GUDGEON (SS-212) launches a torpedo attack on the convoy at 15-28N, 145-58E. LtCdr Post hits and damages SANTO MARU. Listing and down by the stern, she is taken in tow by KENRYU MARU to Saipan where the convoy arrives later that day. Auxiliary minesweeper SEKI MARU No.3 and auxiliary subchaser KYO MARU No. 10 depart from Saipan at 1205 to assist. Auxiliary minesweeper FUMI MARU No. 2 escorts the other ships. SANTO MARU is left moored off Garapan.
11 October 1943:
Departs Saipan for Tateyama in convoy No. 4008 that departed Truk on 8 October for Yokosuka. Convoy No. 4008 also consists of TSUNESHIMA and CHIYO MARUs without escort.
13 October 1943:
The convoy is joined by MANJU, TAIAN, SANKO and TATEBE MARUs, escorted by kaibokan FUKUE, auxiliary minelayer CHOAN MARU and auxiliary subchaser TAKUNAN MARU No. 10.
18 October 1943:
The merged convoy arrives at Tateyama.
19 October 1943:
Departs Tateyama and arrives the same day at Yokosuka.
1 November 1943:
Departs Yokosuka for Truk via Ogasawara Gunto (Bonins) in convoy No. 3101 also consisting of HIDAKA, TAIKOKU, KONEI, HAGURO and SHIBAZONO MARUs and NANKAI MARU No. 2 escorted by destroyers ASANAGI, IKAZUCHI and INAZUMA and auxiliary gunboat CHOAN MARU No. 2.
5 November 1943:
The convoy arrives at Chichi Jima, Bonins. ASANAGI is detached.
E November 1943:
Departs Chichi Jima at an unknown date.
12 November 1943:
About 110 nms NNE of Truk. The convoy is intercepted by LtCdr (later Rear Admiral) Harry Hull’s (USNA ‘32) USS THRESHER (SS-200). At 2200, Hull fires three torpedoes and hits MUKO MARU. At 2218, she sinks at 09-02N, 152-46E. 18 crewmen are KIA.
5 January 1944:
Removed from the Navy List under internal order No. 54.
Author’s Notes:
[1] There were two categories of Zatsuyosen. (Ko) category with an IJN Captain as supervisor aboard and (Otsu) category without.
[2] The Tokusetsu Unsokan class (converted auxiliary replenishment vessel) was newly set up in 1939. Its main role was to supply naval vessels with fuel. If necessary, they transported personnel and war supplies.
Thanks go to Gengoro S. Toda of Japan.
-Gilbert Casse, Bob Hackett and Peter Cundall
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