TONAN MARU NO. 2: Tabular Record of Movement
© 2008-2014 Bob Hackett and Peter Cundall.
14 August 1936:
Osaka. Laid down at Osaka Iron Works as a 19,262-ton whale oil factory ship for Nippon Suisan K. K. (Japan. Fisheries Co., Ltd.) of Tokyo.
11 May 1937:
Launched and named TONAN MARU No. 2.
31 August 1937:
26 September 1937:
Departs Japan for whaling operations for Nippon Suisan K. K. in the Antarctic Ocean.
30 October 1937:
Her owners are notified of the forthcoming requisition of TONAN MARU No. 2 by the IJN under secret instruction No. 1294.
22 February 1941:
Antarctic Ocean. German Rear Admiral Robert Eyssen’s Hilfskreuzer (Auxiliary Cruiser) Schiff 45 KOMET is looking for the Anglo-Norwegian whaling fleets, but his radio operator hears only Japanese traffic. Commerce Raider KOMET discovers a Japanese whaler and later, TONAN MARU No. 2 and 16,801-ton factory ship NISSHIN MARU. Eyssen learns from the Captain of TONAN MARU No. 2 that his potential targets are operating further west.
8 November 1941:
Starts conversion to an auxiliary transport with oil supply capacity at Kure Naval Yard.
10 November 1941:
Registered in the IJN as an auxiliary transport, (Otsu) category and attached in the Kure Naval District with Kure as home port under internal order No. 1391.
23 December 1941:
Davao, Mindanao, Philippines. TONAN MARU No. 2 is a station tanker for the 3rd Fleet. She is attacked and damaged by Dutch Dornier flying boats of GVT-2 from Tondano, Celebes, Netherlands East Indies.
15 January 1942:
Departs Kure for Moji.
16 January 1942:
Arrives at Moji and departs later the same day.
17 January 1942:
Arrives at Osaka.
19 January 1942:
21 January 1942:
Arrives at Tokyo.
26 January 1942:
Departs Tokyo for Mereyon.
E 2 February 1942:
Arrives at Mereyon.
E 3 February 1942:
E 5 February 1942:
Arrives at Truk.
10 February 1942:
Truk. Provides water to auxiliary gunboat CHOAN MARU No. 2 GO. Later leaves Truk for Ponape, Mille and Yokosuka.
1 March 1942:
Arrives at Yokosuka.
8 March 1942:
10 March 1942:
Arrives at Osaka.
13 March 1942:
14 March 1942:
Arrives at Kure.
16 March 1942:
21 March 1942:
Arrives at Mako.
24 March 1942:
Departs Mako for Davao.
14 April 1942:
Passes through Bungo Suido (Strait) heading north.
19 April 1942:
20 April 1942:
Arrives at Kobe.
21 April 1942:
25 April 1942:
At 1500, TONAN MARU No. 2 departs Truk for Kwajalein in convoy No. 5252 escorted by armed merchant cruiser NOSHIRO MARU. 
30 April 1942:
At 0400, arrives at Kwajalein.
10 May 1942:
At 1730 departs from off Futtsu, Tokyo Bay with TAKUNAN MARU escorted by destroyer OKIKAZE and auxiliary netlayer KOKAI MARU. The escorts detach and TONAN MARU No.2 and TAKUNAN MARU head south to Ponape.
25 June 1942:
At 1020 in 28-34N 136-54E sighted a torpedo track but succesfully avoided.
8 September 1942:
Departs Singapore escorted by auxiliary minesweeper TOSHI MARU No. 2 to Sabang.
24 September 1942:
CH-7 and then CH-5 meet TONAN MARU No. 2 off Aru Bank and escort the ship as far as the Bangka Straits.
TONAN MARU No. 2 arrives at Kavieng, New Hanover, Bismarcks ferrying aircraft on her huge deck, as well as delivering fuel oil.
10 October 1942:
Kavieng. At about 1105 (JST), from 3,500 yards outside the harbor, LtCdr John A. Bole’s (USNA ’28) USS AMBERJACK (SS-219) fires four torpedoes at two large ships inside. Bole hits and sinks TONAN MARU No. 2 in shallow water and gets one torpedo hit port side on transport TENRYU MARU moored alongside.
The Japanese pump out and refloat TONAN MARU No. 2 and make emergency repairs.
26 November 1942:
Departs Kavieng under tow by auxiliary transport SUWA MARU, but towing efforts are unsuccessful and both return to Kavieng later that day.
6 December 1942:
A second attempt is made this time successfully, and TONAN MARU No. 2 leaves Kavieng under tow by SUWA MARU.
11 December 1942:
Arrives at Truk where she undergoes temporary repairs, probably by repair ship AKASHI.
16 December 1942:
At 0500, departs Truk under tow by passenger-cargo ship SUWA MARU with tug NAGAURA on the starboard side and an unknown tug on the port side, escorted by destroyer YUZUKI.
27 December 1942:
Destroyer YAMAGUMO takes over escort.
30 December 1942:
Arrives at Yokohama.
Yokohama. TONAN MARU No. 2 is drydocked and undergoes repairs at an unknown shipyard.
31 August 1943:
Removed from the Navy List under internal order No. 1776.
1 September 1943:
Requisitioned again as an Ippan Choyosen (General Requisitioned transport).
4 September 1943:
Truk. TONAN MARU No. 2 is acting as static oil storage.
26 September 1943:
Reclassified as the 22nd Navy ship.
E December 1943:
Transferred to the Senpaku Uneikai (Civilian Administration) and allotted to the IJN (B/C-AK).
17 December 1943:
At 1200 Departs St Jacques in convoy No. 450 also consisting of ZUISHO MARU and one unidentified merchant ship with an unknown escort.
23 December 1943:
At 1500 arrives at Takao.
31 January 1944:
TONAN MARU No.2 departs Takao in convoy No. 357 also consisting of TSUKUBA, ANKO (ex Chinese AN SHING), NORFOLK and TOTTORI MARUs and eight unidentified merchant ships escorted by sub-chasers CH-41 and CH-43 and auxiliary gunboat HUASHAN (KAZAN) MARU.
9 February 1944:
Departs Camranh Bay, French Indochina still in convoy No. 357. At about noon, while TONAN MARU No. 2 is enroute to Nagasaki, LtCdr (later Cdr) Thomas W. Hogan’s (USNA ’31) USS BONEFISH (SS-223) torpedoes and damages her at 11-30N, 109-08E. Hogan claims four hits out of five torpedoes he fires.
Later that day, USN codebreakers intercept and decrypt a message that reads: "Order to Subchasers No. 21, 41, and 43 to attack the submarine that attacked TONAN MARU No. 2.
10 February 1944:
Arrives at St Jacques.
12 February 1944:
Departs St Jacques in convoy SASHI-03 also consisting of TOTTORI, KUNIYAMA, NORFOLK, YOSHU MARUs escorted by old destroyer KARUKAYA.
15 February 1944:
Arrives at Singapore.
TONAN MARU No. 2 is towed to Seletar Naval Base, Singapore. Undergoes repairs by the IJN’s No. 101 Repair Unit.
Repairs are completed.
7 May 1944:
At 1900, TONAN MARU No. 2 departs Singapore for Miri, Borneo in convoy SHIMI-02 also consisting of tankers EIYO, CHIHAYA, SHINEI and NICHINAN MARUs and cargo ships DURBAN, CHINA, FUKUJU and KUNIYAMA MARUs escorted by minesweeper W-18 and subchaser CH-19.
11 May 1944:
At 1545, arrives at Cape Kidurang.
12 May 1944:
At 1005, the convoy arrives at Miri.
20 August 1944:
TONAN MARU No. 2 departs Keelung in convoy TAMO-23 also consisting of 13 unidentified merchant ships escorted by kaibokan CD-5, CD-6, CD-9, CD-18, subchaser CH-58 and auxiliary gunboat CHOHAKUSAN MARU.
22 August 1944:
South China Sea. At about 1900, LtCdr (later Admiral/CINCPACFLT) Bernard A. Clarey’s (USNA ’34) USS PINTADO (SS-387) picks up the convoy. After dark, Clarey moves past a nearby escort and into the center of the convoy. He fires two spreads of 10 torpedoes at TONAN MARU NO. 2 and gets at least two hits. Set ablaze, TONAN MARU No. 2 burns for about three hours, then sinks at 29-53N, 125-19E. Four crewmen are KIA. 
 Although taken from a published source (Komamiya's Senji Yuso Sendan Shi) the dates of this convoy appear dubious. Other sources indicate the ship was at Yokohama on this date.
 TONAN MARU was one of the largest merchant ships sunk by an American submarine during World War II.
Thanks go to Allan Alsleben of Oregon. Thanks also go to John Whitman for info on CNO intercepts of Japanese messages and to Gilbert Casse of France.
- Bob Hackett and Peter Cundall.
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