ZATSUYOSEN!

(SANTO MARU prewar)

IJN SANTO MARU:
Tabular Record of Movement

© 2012-2015 Gilbert Casse, Bob Hackett and Peter Cundall

Revision 1


1 November 1930:
Tama. Laid down by Mitsui Bussan Zosembu K.K. shipyard for Dairen Kisen K.K., as a 3,234-ton cargo ship.

15 April 1931:
Launched and named SANTO MARU.

31 May 1931:
Completed and registered in Dairen, Manchuria (now Dalian, China). Her Gross Registered Tonnage (GRT) is 3,234-tons and Net Registered Tonnage (NRT) is 1,820-tons. [1]

July 1931:
Departs Kong Kong.

14 July 1931:
Arrives at Dairen.

1934:
Her GRT and NRT are respectively changed to 3,266-tons and 1,872-tons. [1]

24 December 1937:
Requisitioned by the IJN. Registered that same day as an auxiliary transport and attached to the Yokosuka Naval District with Yokosuka as homeport under internal orders No. 972 and No. 985. Captain (Rear Admiral posthumously) Maruyama Hidenori (41) (former XO of NAGATO) is appointed temporary Supervisor.

3 January 1938:
Departs Sasebo.

E 5-9 January 1938:
Operates in northern China waters.

16 January 1938:
Arrives at Sasebo.

20 January 1938:
Departs Sasebo.

E 21 January-1 February 1938:
Operates in Chosen (now Korea) waters.

2 February 1938:
Arrives at Sasebo.

7 February 1938:
Departs Sasebo.

13 February 1938:
Arrives at Chefoo (now Yantai), northern China. Departs later that day.

14 February 1938:
Arrives at Ryojun (ex Port-Arthur, now Lushun), northern China.

17 February 1938:
Departs Ryojun.

E 18-24 February 1938:
Operates in northern China waters.

25 February 1938:
Arrives at Saishu-To, Chosen (now Jeju-Do, South Korea).

26 February 1938:
Removed from the Navy list by internal order No. 135.

5 March 1938:
Released to her owners.

5 July 1940:
Captain Maruyama is replaced by an unknown Captain.

25 July 1941:
Osaka. Starts conversion to her military duty at Fujinaga Shipyard.

17 August 1941:
Requisitioned by the IJN.

5 September 1941:
Registered in the IJN as an auxiliary gunboat and attached to the Maizuru Naval District with Maizuru as homeport under internal order No. 1025. Assigned to minelaying missions under internal order No. 1026.

14 October 1941:
Completes conversion.

October 1941:
Attached to Rear Admiral Yoshida Tsunemitsu’s (36) Maizuru Local Defense Squadron.

8 December 1941:
Assigned to Base Defense Unit as auxiliary gunboat No. 1 (Flagship) under Maizuru Naval District orders No. 3 and No. 6.

16 December 1941:
Assigned to Base Defense Unit, first squadron, auxiliary gunboat No. 1 under Maizuru Naval District orders No. 4.

20 December 1941:
Assigned to coastal waters patrol duties under Maizuru Naval District No. 5.

25 December 1941:
Departs Maizuru on drill exercise and returns back later that day.

15 January 1942:
Scheduled to be fitted with a rangefinder under Navy’s secret instruction No. 520.

20 January 1942:
Departs Maizuru.

E 20-22 January 1942:
Undergoes training in Wakasan Wan (Bay).

21 January 1942:
Assignement confirmed to Base Defense Unit, first squadron, auxiliary gunboat No. 1 under Maizuru Naval District order No. 7.

22 January 1942:
Arrives at Kohama, Shimane Prefecture. Departs later.

23 January 1942:
Arrives at Maizuru.

30 January 1942:
Departs Maizuru on minelaying training mission and returns back later in the day.

5 February 1942:
Docks at Maizuru Naval Yard. Flag is temporarily transferred to auxiliary gunboat UNYO MARU No. 1 under Maizuru Naval District order No. 13.

13 February 1942:
Undocked.

18 February 1942:
Becomes Flagship again.

24 February 1942:
Departs Maizuru on training mission.

27 February 1942:
Undergoes AA (Anti Aircraft) fire drill.

28 February 1942:
Arrives back at Maizuru.

16 March 1942:
Departs Maizuru.

E 16-20 March 1942:
Undergoes training in Wakasa Wan.

20 March 1942:
Arrives at Maizuru. That same day, assignment confirmed to Base Defense Unit, first squadron, auxiliary gunboat No. 1 under Maizuru Naval District order No. 9.

24 March 1942:
Departs Maizuru on minelaying training mission and returns back later that same day.

3 April 1942:
Fitted with a Type 97 searchlight.

8 April 1942:
Departs Maizuru.

9 April 1942:
Arrives at Mano-Wan, Niigata Prefecture.

10 April 1942:
Departs Mano-Wan.

11 April 1942:
Arrives at Niigata.

13 April 1942:
Departs Niigata.

14 April 1942:
Arrives at Nanao, Ishikawa Prefecture.

16 April 1942:
Departs Nanao and arrives at Ichinose, Toyama Prefecture later that day.

17 April 1942:
Departs Ichinose.

18 April 1942:
Arrives at Maizuru.

24 April 1942:
Fitted with additional weapons (type unspecified).

6 May 1942:
Assignment confirmed to Base Defense Unit, first squadron, auxiliary gunboat No. 1 under Maizuru Naval District order No. 9.

12 May 1942:
Departs Maizuru.

13 May 1942:
Arrives back at Maizuru.

22 May 1942:
Departs Maizuru on extensive ASW (Anti Submarine Warfare) training and returns back later that day.

23 May 1942:
Departs Maizuru.

E 23-26 May 1942:
Undergoes minelaying training.

25 May 1942:
Flag is temporarily transferred to auxiliary gunboat KATORI MARU.

26 May 1942:
Aircraft warning in Oki-Dogo vicinity.

27 May 1942:
Arrives at Maizuru.

29 May 1942:
Departs Maizuru on Squadron training mission.

4 June 1942:
Arrives at Maizuru. Becomes flagship again.

10 June 1942:
Flag is temporarily transferred to auxiliary gunboat KATORI MARU. Departs Maizuru and returns back later in the day.

11 June 1942:
Becomes flagship again. Departs Maizuru and returns back later in the day.

12 June 1942:
Flag is temporarily transferred to auxiliary gunboat KATORI MARU. Departs Maizuru and returns back later in the day.

15 June 1942:
Departs Maizuru and returns back later in the day.

19 June 1942:
Becomes flagship again.

26 June 1942:
Departs Maizuru on gunfire drill. Returns back later that day and docks at Maizuru Navy Yard.

27 June 1942:
Flag is temporarily transferred to auxiliary gunboat KATORI MARU.

15 July 1942:
Undocked. Shifts anchorage.

20 July 1942:
Assignment confirmed to Base Defense Unit, first squadron under Maizuru Naval District order No. 17.

24 July 1942:
Departs Maizuru on training mission and returns back that same day.

26 July 1942:
Becomes flagship again.

27 July 1942:
Departs Maizuru on combat maneuvers and minelaying training mission.

28 July 1942:
Arrives at Maizuru.

1 August 1942:
Departs Maizuru on training mission and returns back that same day.

11 August 1942:
Departs Maizuru on training mission and returns back that same day.

12 August 1942:
Hoists the flag.

31 August 1942:
Departs Maizuru on ASW training and returns back that same day.

9 September 1942:
Departs Maizuru on training mission and returns back that same day.

10 September 1942:
Attached to Maizuru Naval District Guard Force under secret order No. 574/36. Attached to Maizuru Local Defense Squadron, under secret orders No. 1 and No. 27.

16 September 1942:
Departs Maizuru and arrives at Kohama Wan later in the day.

17 September 1942:
Departs Kohama Wan and arrives at Maizuru that same day.

12 October 1942:
Departs Maizuru.

13 October 1942:
Arrives at Sakaiminato, Tottori Prefecture.

14 October 1942:
Departs Sakaiminato.

15 October 1942:
Arrives at Tsuruga, Fukui Prefecture.

16 October 1942:
Departs Tsuruga and arrives at Maizuru later in the day.

6 November 1942:
Departs Maizuru, calls at Ine, Kyoto Prefecture and returns to Maizuru that same day.

10 November 1942:
Departs Maizuru and arrives at Kohama later in the day.

11 November 1942:
Departs Kohama and arrives at Miyazu, Kyoto Prefecture later that day.

12 November 1942:
Departs Miyazu and arrives at Maizuru later that same day.

24 November 1942:
Detached from Maizuru Local Defense Squadron under Maizuru Naval District secret order No. 31. Assigned to transport missions under Navy confidential order No. 163. Departs Maizuru and arrives at Tsuruga later that day.

25 November 1942:
Departs Tsuruga and arrives at Kohama that same day.

26 November 1942:
Departs Kohama and arrives at Maizuru later that day.

6 December 1942:
Departs Maizuru.

E 6-14 December 1942:
Engaged in a search and rescue mission of a missing Yokohama Ku (Kokutai) flying boat crew off Noto coast.

14 December 1942:
Arrives at Maizuru.

18 December 1942:
Undergoes a refit to comply with her new military duty.

29 December 1942:
Departs Maizuru.

E 29-31 December 1942:
Assists auxiliary emergency tanker KONSAN MARU drifting off Tottori with engine failure, and tows her back to Maizuru.

31 December 1942:
Arrives at Maizuru.

1 January 1943:
Removed from the Navy auxiliary gunboat list by internal order No. 163. Registered that same day as a Fleet auxiliary replenishment vessel (tokusetsu unsokan) attached to the Maizuru Naval District with Maizuru as homeport under Ordinance No. 3. [2]

1943:
IJN Captain Takeda Kiyogo (38) is appointed Commanding Officer (CO) at an unknown date.

13 January 1943:
Departs Tokyo Wan (Bay) for Hokkaido in convoy No. 1113 A also consisting of auxiliary collier/oiler ASAKAZE MARU, IJA transports NIKKO and GOZAN MARUs and civilian cargo ship (C-AK) INARI MARU escorted by minesweeper W-18.

5 February 1943:
Departs Maizuru.

10 February 1943:
Arrives at Kushiro, Hokkaido.

15 February 1943:
Departs Kushiro.

17 February 1943:
Joins convoy No. 2217A also consisting of NORWAY MARU and civilian cargo ship (C-AK) IBURI MARU escorted by torpedo boat MANAZURU.

20 February 1943:
Arrives at Tokyo. Departs later.

1 March 1943:
Departs Yokosuka.

8 March 1943:
Arrives at Saipan.

11 March 1943:
Departs Saipan with auxiliary oiler KOKUYO MARU for Truk.

E 28 April 1943:
Departs Rabaul in a convoy with fleet ammunition ship SOYA escorted by destroyer YUZUKI.

3 May 1943:
Arrives at Truk, Central Carolines.

11 May 1943:
Departs Truk in convoy No. 7112 also consisting of auxiliary oiler KUMAGAWA MARU escorted by destroyer KIYONAMI.

15 May 1943:
The convoy is dissolved off Palau Harbor, Western Carolines. Arrives at Palau. Departs later.

18 May 1943:
Arrives at Fais, Eastern Carolines. Departs later.

31 May 1943:
Departs Palau for Saeki in convoy P-531 also consisting of IJA transports SHOHO, TAIRIN, DOVER and TOYU MARUs and auxiliary collier/oiler ASAKAZE MARU escorted by torpedo boat HATO.

E 6 June 1943:
Auxiliary minesweeper TAMA MARU No. 6 joins the escort at 28-30N 134-45E.

E 8 June 1943:
Auxiliary minesweeper TAKUNAN MARU No. 3 and auxiliary subchaser TAKUNAN MARU No. 8 join the escort at 30-45N 133-05E.

9 June 1943:
Arrives at Saeki. Departs later that day.

10 June 1943:
Arrives at Niihama, Shikoku. Departs later.

June 1943:
Arrives at Tamano, Okuyama Prefecture. Docks at Mitsui Shipbuilding and Engineering K.K. shipyard for maintenance and repairs.

16 July 1943:
Repairs are completed. Undocked.

18 July 1943:
Departs Tamano.

26 July 1943:
Arrives at Yokosuka. Departs later that day for Chichi-Jima, Ogasawara Gunto (Bonins) in convoy No. 3726 also consisting of auxiliary transports KENRYU MARU and EIKO MARU No. 2 GO and IJN requisitioned cargo ship TSUNESHIMA MARU escorted by patrol boat PB-101, and auxiliary gunboat EDO MARU.

29 July 1943:
At 1430 arrives at Chichi-Jima. PB-101 is detached at this point.

1 August 1943:
Departs Chichi-Jima for Saipan, Marianas.

5 August 1943:
Arrives at Saipan. The escorts are detached.

9 August 1943:
At 0830 departs Saipan for Truk escorted by auxiliary submarine chasers CHa-14 and KYO MARU No. 8 and auxiliary gunboat EDO MARU. KYO MARU No. 8 is later detached.

12 August 1943:
Arrives at Truk.

26 September 1943:
At 1000, departs Truk for Saipan in convoy No. 4926 also consisting of auxiliary transports MUKO and KENRYU MARUs and IJN requisitioned TSUNESHIMA MARU escorted by destroyers IKAZUCHI and YUZUKI.

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.

30 September 1943:
SANTO MARU is towed to the inner harbour.

3 October 1943:
Departs Saipan but returns back probably due to previous damage.

14 March 1944:
At 1540, Departs Saipan in convoy No. 4313 B towed by auxiliary transport (ex-auxiliary gunboat) JUZAN MARU. The convoy also consists of IJN requisitioned cargo ship (B-AK) SHIRANE MARU and civilian cargo ship (C-AK) SEIKAI MARU No. 1 escorted by subchasers CH-17 and CH-18 and minesweeper W-21.

17 March 1944:
At 1200, CH-18 and CH-17 are detached from convoy No. 4313-B.

20 March 1944:
At 0700, the convoy arrives safely at Chichi-Jima.

21 March 1944:
At 1700, departs Chichi-Jima still towed by JUZAN MARU.

25 March 1944:
Arrives at Yokosuka.

E March-September 1944:
Yokohama. Under repairs at Mitsubishi Heavy Industries K.K. shipyard.

15 May 1944:
Re-rated as an auxiliary transport, (Otsu) category and attached to the Maizuru Naval District with Maizuru as homeport under internal order No. 681. [3]

15 October 1944:
Departs Kataoka, Shimushu-To, Kuriles (now Zaliv Kozyrevskogo, Ostrov Shumushu) in convoy WO-502 also consisting of unidentified ships and escorts.

24 May 1945:
At 2230, departs Otaru, Hokkaido for Paramushiro, Kuriles in “NU” convoy also consisting of IJA transports HOKUYU and TAISHO (797 GRT) MARUs escorted by kaibokan KUNASHIRI and CD-65.

25 May 1945:
TAISHO MARU's poorly loaded cargo begins to shift. As a result, the convoy returns to Otaru.

26 May 1945:
The convoy re-departs Otaru.

31 May 1945:
At 1403, arrives at Kataoka Wan (Bay), Paramushiro.

30 June 1945:
Removed from the Navy’s list under internal order No. 577. That same day, derequisitioned and released to her owners by secret order 610-No. 14.

15 August 1945:
Cessation of hostilities.

1 February 1946:
U.S. Naval Technical Mission to Japan reports SANTO MARU, SCAJAP No. S-016, as “under repair at Mitsubishi Dockyard, Yokohama”.

Postwar:
Back into commercial service.

6 June 1950:
Wrecked off Aghennasaki, Miyakojima.


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.

[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.

[3] 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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