Japanese Transports

ZATSUYOSEN!
(YOKO MARU prewar)

IJN YOKO MARU:
Tabular Record of Movement

© 2014-2016 Gilbert Casse, Bob Hackett and Peter Cundall
Revision 1

E 1937:
Amagasaki. Laid down by Nakata Zosensho K.K. shipyard for Sanko Kisen K.K. as a 1,050-ton cargo ship.
3 May 1938:
Launched and named YOKO MARU. [1]
15 August 1938:
Completed and registered in Amagasaki.
E 1939:
Requisitioned by the IJA as Army transport No. 437.
14 March 1939:
Departs Wuhu, southern China.
21 April 1939:
Arrives at Nanking, southern China.
16 May 1939:
Departs Nanking.
15 June 1939:
Arrives at Chingkow (now Zhenjiang), southern China.
16 June 1939:
Departs Chingkow.
E 1940:
Released to her owners.
15 February 1941:
Requisitioned by the IJN as a general requisitioned transport (Ippan Choyosen).
1941:
Attached to the Hydrographic Department at an unknown date.
11 June 1941:
Departs Yokosuka.
E June ~ December 1941:
Operates in the South Seas (Japanese mandated islands).
21 December 1941:
Arrives at Takao, Formosa (now Kaohsiung, Taiwan).
26 December 1941:
Departs Takao.
24 January 1942:
Arrives at Yokosuka.
2 March 1942:
Departs Yokosuka.
24 March 1942:
Arrives at Yokosuka.
1 April 1942:
Departs Yokosuka.
24 April 1942:
Arrives at Ominato, Aomori Prefecture.
26 April 1942:
Departs Ominato and arrives that same day at Hakodate, Hokkaido.
29 April 1942:
Departs Hakodate.
16 May 1942:
Arrives at Kushiro, Hokkaido.
19 May 1942:
Departs Kushiro.
20 May 1942:
Arrives at Ominato.
26 May 1942:
Departs Ominato.
16 June 1942:
At 0600 arrives at Ominato.
23 June 1942:
Departs Ominato.
26 June 1942:
Arrives at Yokosuka.
1 August 1942:
Scheduled to be attached to Vice Admiral Hosogaya Boshiro’s (36) Fifth Fleet and assigned from Aug 5 to survey duties under telegram no. 298.
12 August 1942:
At 1300 departs Yokosuka.
15 August 1942:
Arrives at Hakodate.
17 August 1942:
At 1200 departs Hakodate.
24 August 1942:
At 1100 arrives at Attu.
12 October 1942:
Arrives at Ominato.
14 October 1942:
Departs Ominato and arrives later that day at Hakodate.
17 October 1942:
Departs Hakodate.
23 October 1942:
Arrives back at Hakodate.
25 October 1942:
Departs Hakodate.
28 October 1942:
Arrives at Yokosuka.
29 October 1942:
Begins her conversion to new military duty.
1 December 1942:
Registered in the IJN as an auxiliary transport, (Otsu) category attached to the Yokosuka Naval District with Yokosuka as homeport under instruction No. 2213. [2]
15 December 1942:
The conversion is completed.
18 December 1942:
Departs Yokohama in northbound convoy No. 70 also consisting of IJA transport TAKAO MARU escorted by auxiliary gunboat DELHI MARU.
20 December 1942:
Arrives at Shiogama, Miyagi Prefecture.
22 December 1942:
Departs Shiogama.
23 December 1942:
Arrives at Muroran, Hokkaido.
25 December 1942:
Departs Muroran in southbound convoy No. 83 also consisting of civilian cargo ship (C-AK) HOKUTO MARU and IJA transports SHOZAN and LIVERPOOL MARUs escorted by minesweeper W-18.
28 December 1942:
Arrives at Yokosuka.
30 December 1942:
Departs Yokosuka and arrives at Yokohama later in the day.
5 January 1943:
Departs Yokohama in convoy No. 1105B also consisting of IJA transports WAKATSU, HAKUSAN MARUs and TAMON MARU No. 5 and civilian cargo ship (C-AK) TAKE MARU escorted by auxiliary gunboat KEISHIN MARU.
7 January 1943:
Arrives at Shiogama.
9 January 1943:
Departs Shiogama.
10 January 1943:
Arrives at Muroran.
14 January 1943:
Departs Muroran in convoy No. 2113 also consisting of civilian cargo ships (C-AK) HOKUTO, HOKUJU and RYOGA MARUs, civilian passenger/cargo ship (C-APK) JINDAI MARU, IJA transport SEIRYU MARU and an unidentified merchant ship escorted by destroyer NOKAZE.
15 January 1943:
Arrives at Onagawa, Miyagi Prefecture.
21 January 1943:
Departs Onagawa.
22 January 1943:
Arrives at Yokosuka.
25 January 1943:
Departs Yokosuka.
28 January 1943:
Arrives at Chichi Jima, Ogawasara Gunto (Bonins).
10 February 1943:
Departs Chichi Jima.
13 February 1943:
Arrives at Yokosuka.
14 February 1943:
Departs Yokosuka and arrives at Tokyo later that day.
17 February 1943:
Departs Tokyo and arrives at Yokosuka later in the day.
18 February 1943:
Departs Yokosuka and arrives at Tateyama, Chiba Prefecture later that same day.
19 February 1943:
Departs Tateyama and arrives at Yokosuka later that day.
20 February 1943:
Departs Yokosuka, calls at Tateyama; departs there and arrives back at Yokosuka later in the day.
21 February 1943:
Departs Yokosuka and arrives at Tokyo later that day.
24 February 1943:
Departs Tokyo and arrives at Yokosuka later in the day.
26 February 1943:
Departs Yokosuka and arrives at Tokyo later that day.
1 March 1943:
Departs Tokyo and arrives at Yokosuka later that same day.
6 March 1943:
Departs Yokosuka.
8 March 1943:
Arrives at Shiogama.
10 March 1943:
Departs Shiogama.
11 March 1943:
Arrives at Muroran.
13 March 1943:
Departs Muroran.
14 March 1943:
Arrives at Onagawa.
20 March 1943:
Departs Onagawa.
22 March 1943:
Arrives at Yokosuka.
28 March 1943:
Departs Yokosuka.
3 April 1943:
Arrives at Marcus, Ogasawara Gunto.
7 April 1943:
Departs Marcus.
12 April 1943:
Arrives at Yokosuka.
14 April 1943:
Departs Yokosuka and arrives at Tokyo later that same day.
16 April 1943:
Departs Tokyo in convoy No. 7416A also consisting of IJN requisitioned cargo ship (B-AK) CHIYO MARU and IJA shared tanker (A/C-AO) TACHIBANA MARU escorted by survey ship KOMAHASHI.
18 April 1943:
Arrives at Osaka.
19 April 1943:
Departs Osaka.
20 April 1943:
Arrives at Tsukumi, Oita Prefecture, Kyushu.
21 April 1943:
Departs Tsukumi.
22 April 1943:
Arrives at Osaka.
24 April 1943:
Departs Osaka.
26 April 1943:
Arrives at Yokosuka. Departs there and arrives at Yokohama later in the day.
27 April 1943:
Departs Yokohama.
29 April 1943:
Arrives at Kobe. Departs later that day.
30 April 1943:
Arrives at Tsukumi.
1 May 1943:
Departs Tsukumi.
2 May 1943:
Arrives at Kobe.
3 May 1943:
Departs Kobe.
5 May 1943:
Arrives at Yokosuka.
8 May 1943:
Departs Yokosuka.
14 May 1943:
Arrives at Marcus.
16 May 1943:
Departs Marcus.
19 May 1943:
Arrives at Chichi Jima.
26 May 1943:
Departs Chichi Jima.
29 May 1943:
Arrives at Yokosuka.
3 June 1943:
Departs Yokosuka.
8 June 1943:
Arrives at Marcus.
12 June 1943:
Departs Marcus.
16 June 1943:
Arrives at Yokosuka.
21 June 1943:
Departs Yokosuka.
24 June 1943:
Arrives at Chichi Jima.
9 July 1943:
Departs Chichi Jima.
11 July 1943:
Arrives at Yokosuka.
17 July 1943:
Departs Yokosuka.
20 July 1943:
Arrives at Chichi Jima.
24 July 1943:
Departs Chichi Jima.
25 July 1943:
Arrives at Iwo Jima, Ogasawara Gunto.
2 August 1943:
Departs Iwo Jima.
3 August 1943:
Arrives at Chichi Jima.
5 August 1943:
Departs Chichi Jima.
8 August 1943:
Arrives at Yokosuka.
14 August 1943:
Departs Yokosuka in convoy with IJN requisitioned cargo ship (B-AK) TAIYO MARU (670 GRT) and possibly others with unknown escort.
17 August 1943:
Arrives at Chichi Jima.
19 August 1943:
Departs Chichi Jima.
22 August 1943:
Arrives at Marcus.
29 August 1943:
Departs Marcus.
1 September 1943:
Arrives at Chichi Jima.
3 September 1943:
Departs Chichi Jima.
6 September 1943:
Arrives at Yokosuka.
10 September 1943:
Departs Yokosuka for Chichi Jima in a convoy consisting of unidentified merchant ships and escort.
11 September 1943:
S of Mikura Jima, Izu Shoto (archipelago). About midnight, Cdr (MOH posthumously) Samuel D. Dealey’s (USNA ’30) USS HARDER makes radar contact with the convoy. After running ahead to improve the submarine firing position, at 0015, Dealey fires a spread of three torpedoes and scores two hits on YOKO MARU. The first one is a dud but the second breaks the transport’s back and she goes dead in the water, sinking by the stern. Eight crewmen are KIA.
12 September 1943:
YOKO MARU finally sinks at 33-49N, 139-30E, about 2.7 nautical miles WSW Mikura Jima.
1 November 1943:
Removed from the Navy’s list under instruction No. 2288.

Authors' Notes :
[1] Not to be confused with IJA transport No. 1071 (860 GRT, ’41) or IJN shared tanker (957 GRT, ’43). [2] 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.

Gilbert Casse, Bob Hackett and Peter Cundall

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