YUSOSEN!


(GENYO MARU prewar as an Asano Bussan tanker)

IJN GENYO MARU:
Tabular Record of Movement


© 1998-2014 Bob Hackett and Peter Cundall.
Revision 6


1937:
Kobe. Completed as the 10,018-ton merchant tanker GENYO MARU by Kawasaki for Asano Bussan, Tokyo

2 November 1941:
Requisitioned by the IJN and registered in the Sasebo Naval District.

23 November 1941:
Sasebo Naval Yard. Begins conversion to a naval auxiliary.

15 December 1941:
The conversion is completed. Attached to Vice Admiral Ibo Takahashi's Third Fleet.

18 December 1941:
Departs Sasebo.

29 December 1941:
At Palau at 1549 refuels PB-1.

9 January 1942:
Arrives at Mako, Pescadores.

13 January 1942:
Takao. Refuels auxiliary gunboat KISO MARU.

17 January 1942:
Departs Takao.

1 February 1942:
Arrives at Sasebo.

6 February 1942:
Departs Sasebo.

13 February 1942:
At Staring Bay at 1405 PB-1 refuels from GENYO MARU.

20 February 1942:
Formosa Strait. Collides with and damages Army cargo ship DAKAR MARU. Later that day, arrives at Mako.

27 February 1942:
Departs Mako.

11 March 1942:
GENYO MARU and KAMIKAZE and SENKO MARUs are reported in the Macassar area being escorted by the minelayer WAKATAKA.

28 March 1942:
Arrives at Sasebo.

1 April 1942:
Departs Sasebo.

22 May 1942:
Arrives at Sasebo.

30 May 1942: Operation "MI" - The Battle of Midway:
Departs Sasebo in Vice Admiral (later Admiral) Kondo Nobutake's (35) (former CO of KONGO) Second Fleet, Midway Invasion Force with Captain Murao Jiro's (39) Supply Group’s oilers SATA, TSURUMI and KENYO MARU and repair ship AKASHI.

4 June 1942:
Arrives at Truk.

13 June 1942:
Reassigned to the Northern Naval Force's (Fifth Fleet) 2nd Group.

24 June 1942:
Arrives at Ominato.

28 June 1942:
Departs Ominato.

13 July 1942:
Arrives at Hiroshima Bay.

2 August 1942:
Departs Kure and transits the Bungo Straits.

7 August 1942: American Operation “Watchtower” – The Invasion of Guadalcanal, Solomons:
Rear Admiral (later Admiral) Richmond K. Turner's (USNA ’08) Amphibious Task Force 62, covered by Vice Admiral (later Admiral) Frank J. Fletcher’s (USNA ’06) Task Force 61 and Rear Admiral (Admiral posthumously) John S. McCain's (USNA ’06) Task Force 63’s land-based aircraft, lands MajGen (later Gen/MOH/Commandant) Alexander A. Vandergrift’s 1st Marine Division on Florida, Tulagi, Gavutu, Tanambogo and Guadalcanal opening the campaign to retake the island.

10 August 1942:
Departs Truk for Rabaul with destroyer HAMAKAZE.

14 August 1942:
Arrives at Rabaul.

3 September 1942:
Arrives at Shimotsu.

8 September 1942:
Reassigned to the Guadalcanal Transport Replenishment Group to support Naval Forces. That same day, departs Kanokawa and transits the Bungo Straits heading south.

7 October 1942:
Arrives at Sasebo.

16 October 1942:
Departs Sasebo.

7 November 1942:
Transits the Bungo Straits enroute to Kure and Nagasaki in a convoy also consisting of tankers KENYO, NIPPON and TOEI MARUs. Arrives at Nagasaki

11 November 1942:
Departs Nagasaki in a convoy also consisting of KENYO MARU escorted by torpedo boat HATO.

21 November 1942:
Arrives at Rabaul.

2 March 1943:
At 1130 arrives at Saipan from Truk.

3 March 1943:
At 1200 due to sail from Saipan for Singapore.

30 July 1943:
Arrives at Truk.

31 July-2 August 1943:
Truk. Refuels NOWAKI and another DesDiv 27 destroyer, then refuels ISOKAZE and AKEBONO.

19 August 1943:
Departs Rabaul in convoy No. 2194 with an unidentified escort.

23 August 1943:
Arrives at Truk.

22 September 1943:
At 1500, GENYO MARU is attacked by LtCdr (later Cdr) Victor B. McCrea’s (USNA ’32) USS HOE (SS-258) in a submerged attack at 10-07N, 146-57E. McCrea fires six torpedoes, of which GENYO MARU’s lookouts spot the tracks of four. McCrea reports two hits and his target down by the stern and listing. Later at 10-10N 147-05 the destroyer YUZUKI meets up with GENYO MARU and escorts the ship to Truk.

23 September 1943:
Arrives at Truk.

6 October 1943:
At 1600, departs Truk via the South Channel with an unidentified destroyer.

10 October 1943:
At 0900, departs Truk with destroyer UMIKAZE that escorts the ship some distance before returning to Truk.

20 October 1943:
At 1000, departs Balikpapan with oiler AZUMA MARU escorted by patrol boat PB-102 (ex-USS STEWART, DD-224).

27 October 1943:
At 07-50N 143-00E destroyer YUZUKI meets up with the two tankers that are at this point unescorted.

29 October 1943:
At 0500, arrives Truk in convoy consisting of GENYO and AZUMA MARUs escorted by destroyer YUZUKI.

5 November 1943:
GENYO MARU departs Truk for Singapore in convoy with oiler HOYO MARU escorted by old destroyer YAKAZE.

6 November 1943:
150 miles NW of Truk. At 0200, the convoy is attacked by LtCdr (later Rear Admiral) Roy M. Davenport’s (USNA ’33) USS HADDOCK (SS-231) in a surface radar attack at 07-54N, 150-06E. Davenport fires six torpedoes at GENYO and HOYO MARUs from 3,000 yards. He then swings around and fires all four stern torpedoes at YAKAZE from about 4,000 yards.

The convoy switches on searchlights and opens fire. At 0005 (JST), YAKAZE steaming at 12 knots rams GENYO MARU’s starboard aft section. The escort’s bow is bent badly and speed reduced to 6 knots. YAKAZE returns to Truk on 7th. Davenport pulls off, reloads and about an hour later makes a second attack. He fires his last four torpedoes from 3,000 yards, two at each oiler, and claims sinking both. Actually, HOYO MARU is hit, set afire and abandoned.

GENYO MARU and YAKAZE return to Truk. Subchaser CH-33 assists GENYO MARU. Near Orolup Islands, auxiliary minelayer KINJO MARU joins as escort.

Later, light cruiser NAGARA departs Truk and tows HOYO MARU back to port.

12 November 1943:
Departs Truk in a convoy consisting of oilers GENYO and AZUMA MARUs escorted by destroyer MATSUKAZE.

30 November 1943:
Departs Truk for Singapore.

9 December 1943:
Departs Balikpapan for Truk.

14 December 1943:
At 1630 departs Palau escorted by destroyer HAYANAMI and convoy later met en route by destroyer INAZUMA.

19 December 1943:
Arrives at Truk.

30 December 1943:
Departs Truk escorted by the destroyer TACHIKAZE.

3 January 1944:
At 0731 departs Palau escorting convoy NE-202 consisting of tanker GENYO MARU also escorted by the destroyer TACHIKAZE. The destroyer detaches soon after leaving Palau.

5 January 1944:
At 1245 in position 04-04N 125-12E meets up with tanker KOKUYO MARU being escorted by the Storeship ARASAKI.

7 January 1944:
At 1320 arrives at Balikpapan.

15 January 1944:
Departs Palembang.

16 January 1944:
Arrives at Singapore.

25 January 1944:
At 0730, departs Singapore in convoy HI-32 consisting of oilers GENYO, OMUROSAN, TATEKAWA, ITSUKUSHIMA and KUROSHIO MARUs and passenger-cargo ship HOKUROKU MARU escorted by carrier CHITOSE and destroyer YUKIKAZE.

4 February 1944:
CHITOSE detaches and heads to Sasebo. At 1100, the convoy arrives at Moji. Later that day, GENYO MARU arrives at Tokuyama.

7 February 1944::
Departs Tokuyama.

11 March 1944:
At 1900, convoy HI-53 arrives at Takao from Moji. The convoy probably consists of tankers GENYO and MIRI MARUs and an unidentified ship. Destroyer AMAGIRI and kaibokan KANJU join the escort.

18 March 1944:
At 1730, arrives at Singapore.

8 April 1944:
Departs Davao, Philippines.

10 April 1944:
Arrives at Tarakan, Borneo. Loads a cargo of refined oil.

12 April 1944:
Departs Tarakan.

14 April 1944:
Arrives at Balikpapan, Borneo. Loads fuel oil.

18 April 1944:
Departs Balikpapan.

26 April 1944:
Arrives at Saipan, Marianas. Discharges fuel oil.

29 April 1944:
Departs Saipan.

7 May 1944:
Arrives at Balikpapan. Loads fuel oil.

13 May 1944:
Departs Balikpapan.

15 May 1944:
Arrives at Tawi Tawi, Philippines.

2 June 1944:
Tawi Tawi. Assigned to Vice Admiral Ozawa’s 2nd Supply Force. Refuels super-battleships MUSASHI and YAMATO.

3 June 1944:
At 1100, 2nd Supply Force’s oilers GENYO and AZUSA MARUs escorted by destroyers YUKIKAZE and MAIKAZE depart Tawi Tawi for Point "I", a holding position 130 miles E of northern Mindanao, Philippines. Later that day, they depart Point I for Guimaras located between Negros Island and Panay Islands.

6 June 1944:
Departs Balikpapan, Borneo, probably after loading fuel oil to replenish the fleet.

8 June 1944:
Off Guimaras Island.

13 June 1944: Operation “A-GO” - The Defense of the Marianas:
Hashirajima. From his flagship light cruiser OYODO, the CINC, Combined Fleet, Admiral Toyoda Soemu, (former CO of HYUGA), signals the fleet to activate Operation "A-GO".

14 June 1944:
Guimaras, Philippines. Vice Admiral Ozawa Jisaburo's Mobile Fleet's Main Body arrives and the 2nd Supply Force begins refueling operations.

15 June 1944:
Guimaras. At 0800, refueling is completed and the Mobile Fleet's Main Body departs. At 0830, the 2nd Supply Force and destroyers YUKIKAZE and UZUKI depart. They heads through the Visayan Sea and San Bernardino Strait into the Philippine Sea towards the designated refueling rendezvous holding area.

16 June 1944:
NW of Palau. At about 2300, LtCdr (Later Rear Admiral) Herman J. Kossler's (USNA ’34) USS CAVALLA (SS-244) is running on the surface towards the San Bernardino Strait. Her SJ radar detects four targets. Kossler closes and identifies two oilers escorted by two destroyers on a southeasterly course. Kossler increases speed and begins an "end around" to get ahead of the small convoy.

17 June 1944:
At 0315, Kossler completes the "end around" and dives to begin an approach. He closes on either AZUSA MARU or GENYO MARU and sets up for an attack. Just as he is about to fire, one of the destroyers apparently spots his 'scope and charges USS CAVALLA. Kossler takes the submarine deep as the destroyer passes overhead. He remains submerged until about 0500. When USS CAVALLA again comes to persicope depth, the convoy is nowhere in sight. At 0545, USS CAVALLA surfaces and gets off a contact report to COMSUBPAC.[1]

At 1440, destroyer UZUKI joins GENYO MARU. At 1550, destroyer AKIZUKI also arrives. At 1845, destroyers AKIZUKI and URAKAZE are detached.

18 June 1944:
At 0730, oiler HAYASUI, destroyers HATSUSHIMO, YUNAGI and TSUGA all join the convoy. At 1515, light cruiser NATORI also joins the convoy.

19 June 1944:
At 0515, NATORI is detached. At 2400, GENYO MARU is at 15-20N, 134-40E.

20 June 1944: The Battle of the Philippine Sea:
At 0620, the fleet reverses course. At 1746, a formation of Grumman "Avenger" TBF torpedo-bombers and Curtiss "Helldiver" SB2C-1 dive-bombers attacks the ships.

At 1806, GENYO MARU is dive-bombed by three SB2C-1 dive-bombers from Task Force 58's USS WASP (CV-18) Air Group 86. Bombs hit the port gangway near the machinery room, about 10 yards from the starboard bow and near the portside of the bridge wrecking the area. Near misses split GENYO MARU's sides and cause her engine to stop.

At 1850, AZUSA MARU takes GENYO MARU in tow. About 1,000 tons of water are taken onboard. This slows the towing and the line breaks several times. Since the enemy force is present nearby, this creates an impossible situation.

950 miles E of Luzon. At 2150, GENYO MARU's flag is hauled down. At 2200, her Kingston valves are opened and scuttling commences. At 2205, the crew abandons ship. At 2220, after UZUKI removes the crew, she scuttles GENYO MARU with gunfire. The ship is set afire, explodes and sinks at 15-35N 133-30E.

10 August 1944:
Removed from the Navy List.


Authors' Note:
[1] As a result of Kossler's contact report, COMSUBPAC repositions several submarines, among them USS CAVALLA and LtCdr James W. Blanchard's USS ALBACORE (SS-218). On 19 Jun '44, Blanchard torpedoes and sinks the new fleet carrier TAIHO. Later that same day, Kossler sinks SHOKAKU, the penultimate surviving carrier of the attack on Pearl Harbor.

Thanks for assistance go to Sander Kingsepp of Estonia and Allan Alsleben of Oregon.

Credit for the photo of GENYO MARU goes to Erich Muehlthaler of Germany via Gilbert Casse of France. Thanks to Mr. Gilbert Casse for extra information in revision 4 and Mr. John Whitman of USA for extra information in Revision 5.

- Bob Hackett and Peter Cundall.


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