YUSOSEN!

(RONSAN MARU pre-war )

RONSAN MARU
Tabular Record of Movement


© 2012 Bob Hackett


27 March 1929:
Tamano. Laid down at Mitsui Bussan, K. K. as a 2,735-ton cargo ship for Dairen Kisen, K. K., Dairen (Dalian), Manchuria.

24 August 1929:
Launched and named RONSAN MARU. [1]

30 September 1929:
Completed.

1 December 1942:
Tamano. Begins conversion to an emergency tanker (Ohkyu Yusosen) at Mitsui Bussan, K. K.

30 December 1942:
Completes conversion.

16 April 1943:
RONSAN MARU departs Takao in convoy No. 252 consisting of JUYO MARU and ten unidentified merchant ships escorted by patrol boat PB-36.

22 April 1943:
Arrives at Moji.

21 June 1943:
RONSAN MARU departs St Jacques, Indochina escorting convoy No. 404 consisting of KONSAN and TAINAN MARU and seven unidentified merchant ships escorted by kaibokan MASUWA.

27 June 1943:
Arrives at Takao.

2 July 1943:
RONSAN MARU departs Takao escorting convoy No. 278 consisting of LONDON and MANSHU MARUs and five unidentified merchant ships escorted by destroyer KURETAKE.

6 July 1943:
Arrives at Moji.

26 July 1943:
RONSAN MARU departs Takao in convoy No. 762 consisting of fleet oiler TSURUMI and tankers NANMAN, TAIKOKU and SHOYU MARUs and four unidentified merchant ships escorted by torpedo boat SAGI and auxiliary patrol boats KAIYO MARU No. 1 and KAIYO MARU No. 2.

30 July 1943:
Arrives at Manila.

24 August 1943:
RONSAN MARU departs St Jacques in convoy No. 421 consisting of tanker TAKETOYO MARUs and three unidentified merchant ships escorted by patrol boat PB-36.

30 August 1943:
Arrives at Manila.

E 12 November 1943:
RONSAN MARU departs Paramushiro, Kuriles in a convoy consisting of SHONAN MARU and refrigerator ship KOKO MARU escorted by kaibokan HACHIJO.

E 15 November 1943:
In heavy weather, the convoy separates.

17 November 1943:
At 0400, SHONAN MARU and HACHIJO arrive at Otaru. RONSAN MARU arrives later.

16 December 1943:
RONSAN MARU arrives at Tokuyama Naval Fuel Depot Refuels and departs that same day.

17 December 1943:
Departs for Takao in an unidentified convoy probably from Moji.

23 December 1943:
Arrives at Takao.

December 1943:
Departs Takao for Miri, Borneo.

13 January 1944:
At 1500, RONSAN MARU departs Manila in convoy No. 3102 consisting of tankers KOSHIN, SEINAN, NITTATSU and TAKETOYO MARUs and cargo ships TEIRYU (ex-German AUGSBURG) and NITTAI MARUs escorted by destroyer WAKATAKE.

20 January 1944:
At 1500 arrives at Miri.

21 January 1944:
At 1200, RONSAN MARU departs Miri escorting convoy 3202 consisting of tankers KOSHIN, SEINAN and NITTATSU MARUs escorted by destroyer WAKATAKE.

22 January 1944:
At 1736, LtCdr Donald F. Weiss' USS TINOSA (SS-283) attacks the convoy. Weiss torpedoes and sinks KOSHIN MARU at 07-27N, 115-07E. 22 crewmen are KIA.

Weiss' also torpedoes and sinks SEINAN MARU at 07-19N, 116-52E. 29 crewmen and 16 gunners are KIA. WAKATAKE drops 17 depth charges, but TINOSA escapes.

E 23 January 1944:
The remainder of the convoy shelters at Labuan.

26 January 1944:
Off Labuan. The convoy joins convoy 3203 that sailed from Miri, Borneo that same day. The combined convoy consists of NITTATSU MARU, tankers RONSAN, SAN PEDRO and TAKETOYO MARUs and four unidentified merchant ships escorted by WAKATAKE and torpedo boat MANAZURU.

31 January 1944:
At 1300, arrives at Manila.

E 9 February 1944:
RONSAN MARU departs Moji for Mako (Makung) in an unidentified convoy.

12 February 1944:
East China Sea. LtCdr Russell Kefauverís USS TAMBOR (SS-198), sights smoke at 25,000 yards. By 1730, Kefauver is able to make out the convoy consisting of four ships and three escorts.

At 1921, unable to maneuver for a submerged attack, Kefauver surfaces TAMBOR and closes the targets on her four diesel engines. At 2052, he fires three torpedoes by SJ radar and submerges to avoid the escorts.

Between 2052 and 2054, TAMBORís crew hears one hit that sinks RONSAN MARU off Okinoerabu Island, about 40 miles SW of Amami O-Shima, Ryukyus at 27-44N, 128-42E. 17 crewmen and 2 gunners are KIA.

Between 2056 and 2148, TAMBOR endures 17 depth charges, but escapes undamaged.


Author's Notes:
[1] Also known as RONZAN MARU.

[2] Photo credit goes to Gilbert Casse of France.

[3] Thanks goes to Peter Cundall of Australia for some additional JACAR data about RONSAN MARU.

- Bob Hackett


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