Japanese Auxiliary Oilers

YUSOSEN!

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(Wartime Standard Merchant Tanker 1TL)

IJN RYOEI MARU:
Tabular Record of Movement
© 2008-2022 Bob Hackett and Peter Cundall.
Revision 6

20 September 1943:
Aioi. Laid down by Harima Zosensho K.K. as a 10,016-ton Standard Merchant 1TL tanker for Nitto Kisen K. K., Tokyo.
21 January 1943:
Launched and named RYOEI MARU.
29 February 1944:
Completed and registered in Tokyo. Her Gross Registered Tonnage (GRT) and Net Registered Tonnage (NRT) respectively are 10,016-tons and 7,315-tons. Her call sign is JVCT. That same day requisitioned by the Ship Transport Association. [1]
1 March 1944:
Departs Harima.
4 March 1944:
Arrives at Iwakuni.
11 March 1944:
Departs Iwakuni.
12 March 1944:
Arrives at Amagasaki.
15 March 1944:
Departs Amagasaki.
16 March 1944:
Arrives at Iwakuni and departs later that day.
18 March 1944:
Designated as the 37th Navy ship.
19 March 1944:
RYOEI MARU departs Moji for Singapore in convoy HI-55 also consisting of IJA oilers OTORISAN and TENSHIN MARUs, IJN fleet oilers, ASANAGI and TARAKAN MARUs and passenger liner KACHIDOKI MARU (ex-PRESIDENT HARRISON) and six unidentified merchant ships escorted by destroyer HARUKAZE.
24 March 1944:
At 1200 the convoy arrives at Takao, Formosa (now Kaoshiung, Taiwan). The six unidentified ships and destroyer HARUKAZE are detached. She is replaced by kaibokan MATSUWA and torpedo boat HATO.
26 March 1944:
The convoy departs Takao Takao now consisting of IJA oilers OTORISAN and TENSHIN MARUs, IJN fleet oilers, ASANAGI and TARAKAN MARUs and IJA transport KACHIDOKI MARU (ex-PRESIDENT HARRISON) escorted by kaibokan MATSUWA and torpedo boat HATO. Soon after departure RYOEI and TENSHIN MARUs develop unknown problems and return to Takao.
1 April 1944:
RYOEI MARU departs Moji for Singapore in convoy HI-57 also consisting of IJN fleet oilers ITSUKUSHIMA and OMUROSAN MARUs and IJA oiler OTOWASAN MARU, IJA landing craft depot ships SHINSHU and MAYASAN MARUs, transports SEIA and KINUGASA MARUs and and either IJA oiler ZUIHO MARU or IJA oiler SHINCHO MARU escorted by escort carrier KAIYO, kaibokan IKI, SHIMUSHU, CD-8, CD-9 and torpedo boat SAGI.
2 April 1944:
The convoy encounters extremely severe weather and returns to Moji.
3 April 1944:
At 0600, the unchanged convoy departs Moji.
7 April 1944:
At 1450, arrives at Takao. IJN Transport HOKKAI MARU joins the convoy.
8 April 1944:
At 1000, departs Takao.
12 April 1944:
At 1930, arrives at Camranh Bay, French Indochina (now Vinh Cam Ranh, Vietnam).
13 April 1944:
At 1200, departs Camranh Bay.
16 April 1944:
At 1240, arrives at Singapore.
21 April 1944:
At 0700, RYOEI MARU departs Singapore for Moji in convoy HI-58 also consisting of IJN fleet oilers ITSUKUSHIMA and OMUROSAN MARUs and IJA oiler OTOWASAN MARU and IJA oiler ZUIHO MARU, IJA transport KACHIDOKI MARU (ex PRESIDENT HARRISON), Army Landing craft depot ships SHINSHU and possibly MAYASAN MARUs escorted by escort carrier KAIYO and kaibokan IKI, ETOROFU, SHIMUSHU, CD-8 and CD-9.
24 April 1944:
E of Saigon, French Indochina (now Ho Chi Minh City, Vietnam). USS ROBALO (SS-273) under LtCdr Manning M. Kimmel (USNA ’35) (son of Admiral H. E. Kimmel, (USNA ’04) former CINCPACFLT at Pearl Harbor) attempts to attack the convoy, but is sighted by a Nakajima B5N2 "Kate” of the 931st NAG detachment from KAIYO. The B5N2 drops one 250-kg depth-charge on the submerged submarine and causes medium damage.
3 May 1944:
HI-58 arrives at Moji.
6 May 1944:
Requisitioned by the IJN. That same day, arrives at Kure.
9 May 1944:
Registered in the IJN under internal order No. 642-2 and attached to the Kure Naval District as an auxiliary oiler. Her home port is Kure. Tactically assigned to the Combined Fleet as a Ko category special transport. Attached to the First Mobile Fleet First Supply Unit under Combined Fleet wireless order No. 80. [2]
10 May 1944:
Departs Kure.
11 May 1944:
Arrives at Moji.
12 May 1944:
At 0400, RYOEI MARU departs Moji for Singapore in convoy HI-63 consisting of cargo liners/transports SANUKI, SANYO, AWA, TEIA (ex-French ARAMIS), USSURI and NISSHO MARUs, Army Landing craft depot ships KIBITSU and TAMATSU MARUs, IJN oiler KYOKUHO MARU and IJA oiler OTOWASAN MARU escorted by kaibokan MATSUWA, IKI, CD-9 and CD-15. SANUKI MARU and the other transports, except TAMATSU, KIBITSU and NISSHO MARUs, carry troops bound for Burma (now Myanmar).
18 May 1944:
At 1800, arrives at Manila. TAMATSU, SANYO, KIBITSU and NISSHO MARUs are detached.
20 May 1944:
At 2000, the remaining eight ships in HI-63 depart Manila with the same escort.
24 May 1944:
150 miles W of Sarawak, British Borneo (now Malaysia). LtCdr (later Cdr) James W. Davis' (USNA ’30) USS RATON (SS-270) attacks the convoy. At about 0220 (JST), IKI is hit by two torpedoes. One hits aft, one hits below the bridge. IKI breaks into three sections and sinks in less than twenty minutes. A total of 160 sailors, including IKI’s skipper LtCdr Nakao Kusuo (57) are KIA; 18 are rescued by ETOROFU. Nakao Kusuo is promoted to Cdr, posthumously. Rear Admiral the Baron, Ijuin Matsuji’s (43) (former CO of KONGO) is also KIA. He is promoted Vice Admiral, posthumously. In the same attack, Davis lightly damages MATSUWA at 01-17N 107-53E. The rest of HI-63 escapes unscathed. [3]
25 May 1944:
At 1130 arrives with IJN oiler KYOKUHO MARU at Singapore escorted by kaibokan MATSUWA.
27 May 1944:
At 2000 the remainder of the convoy arrives at Singapore escorted by kaibokan CD-9 and CD-15.
1 June 1944:
Departs Singapore.
2 June 1944:
In Banka Strait, Netherlands East Indies (now Indonesia) first meets up with IJN oiler ASANAGI MARU and then at 2330 at 225° and 2 nautical miles of the Dapur Island Lighthouse, Netherlands East Indies (now Indonesia) meets up with minesweeper W-101 that is to escort the ships. The ships anchor and wait at this point.
3 June 1944:
At 0500 departs the temporarily Bangka Strait anchorage with IJN oiler ASANAGI MARU escorted by minesweeper W-101.
5 June 1944:
At 0800 south off Laut Island, Borneo, Netherlands East Indies (now Kalimantan, Indonesia) minesweeper W-101 detaches and is replaced by subchaser CH-3. Later that day the convoy arrives at Balikpapan.
9 June 1944:
Departs Balikpapan, Borneo, Netherlands East Indies (now Kalimantan, Indonesia) with storeship ARASAKI likely for Tawi Tawi, Philippines. At unkown time and location both reverse course and return to Balikpapan. Destroyer WAKATSUKI meets up with them and escorts them back to Balikpapan.
10 June 1944:
Arrives at Balikpapan.
14 June 1944:
At 0930 departs Balikpapan in Kyokuho Maru convoy consisting of KYOKUHO, OKIGAWA and RYOEI MARUs escorted by kaibokan MANJU.
18 June 1944:
Arrives off Masapilit Point, Buad Island (off W coast of Samar), Philippines. [4].
21 June 1944:
Departs Masapilit.
22 June 1944:
KYOKUHO MARU breaks down. OKIGAWA MARU begins towing preparations, but discontinues them because of possible enemy attack. At 1400, arrives at Cabugao Bay, on the S coast of Catanduanes Island, Philippines.
23 June 1944:
At 0600, convoy departs Cabugao Bay. At 0840, enters Albay Gulf. Later that day, arrives at Legaspi, Philippines.
24 June 1944:
Departs Legaspi with IJN oiler OKIGAWA MARU escorted by kaibokan MANJU.
25 June 1944:
Arrives at Guimaras, Philippines.
26 June 1944:
Departs Guimaras. Joins up with NICHIEI, OKIGAWA and AZUSA MARUs escorted by destroyers HATSUSHIMO, YUKIKAZE and UZUKI and kaibokan CD-22 and MANJU.
26 June ~ 1 July 1944:
The destroyer YUKIKAZE runs aground on the Pepitas Rocks, Philippines. Destroyers HIBIKI and YUNAGI and fleet oiler HAYASUI assist YUKIKAZE refloat. Later calls at Gato island Visayan Sea, Philippines and Hashima (Gunkan) Island near Nagasaki.
2 July 1944:
Arrives at Kure.
3 July 1944:
Hull repairs begin.
4 July 1944:
Kure. RYOEI MARU arrives alongside NICHIEI MARU to take most of the balance of her cargo.
17 July 1944:
Returns to the Combined Fleet. At 0755 departs Kure in a convoy also consisting of NICHIEI, AZUSA and OKIGAWA MARUs escorted by destroyers SATSUKI, YUZUKI and UZUKI, kaibokan MANJU and submarine chasers CH-30 and CH-33.
20 July 1944:
At an unknown location, NICHIEI MARU refuels subchaser CH-33.
22 July 1944:
At 0640 destroyer SATSUKI meets with RYOEI MARU that has apparently separated.
23 July 1944:
At 0847 AZUSA and NICHIEI MARUs arrive at Manila escorted by CH-30 and CH-33. NICHIEI MARU refuels subchasers CH-30 and CH-33.
24 July 1944:
At 1010 OKIGAWA MARU suffers an engine breakdown. At 1340 arrives at Manila escorted by UZUKI, SATSUKI and YUZUKI. NICHIEI MARU refuels destroyer YUZUKI.
25 July 1944:
At 0644 refuels destroyer YUZUKI in Manila Bay.
27 July 1944:
At 0558, RYOEI MARU departs Manila for Singapore in the "Nichiei Maru" convoy consisting of oilers NICHIEI, and OKIGAWA MARUs escorted by DesDiv 30’s YUZUKI, UZUKI and SATSUKI and kaibokan MANJU.
29 July 1944:
At 1255, a fire breaks out in RYOEI MARU's engine room, but is successfully extinguished. At 1320 OKIGAWA MARU suffers an engine breakdown.
1 August 1944:
At 1539, arrives at Singapore.
7 August 1944:
At Lingga anchorage, Riau Archipelago, Netherland East Indies (now Indonesia) Supply training begins Refuels destroyer URAKAZE.
9 August 1944:
Supply training ends. Departs Lingga anchorage and arrives at Singapore later this day.
10 August 1944:
At 0800, RYOEI MARU departs Singapore for Kure in the "Nichiei Maru” convoy also consisting of oilers NICHIEI and OKIGAWA MARUs escorted by DesDiv 30 and kaibokan MANJU.
11 August 1944:
At 1000 OKIGAWA MARU suffers an engine breakdown. At 1740, OKIGAWA MARU and SATSUKI are detached and return to Singapore.
17 August 1944:
At 1350, arrives at Mako, Pescadores (now Magong, Penghu islands, Taiwan). Departs at 1750.
21 August 1944:
Arrives at Hashirajima, near Kure. Assigned that same day to refuel the 2nd Raiding Force ships under Navy’s telegram No. 368. Refuels battleship YAMASHIRO, hybrid battleship/carrier ISE, aircraft carrier JUNYO, destroyers MAKI and SUZUTSUKI and heavy cruiser SUZUYA.
23 August 1944:
Departs Hashirajima on towing and supply training with destroyer SUZUTSUKI. Arrives back at Hashirajima later this day. Departs Hashirajima later that day and arrives at Kure later this same day.
24 August~5 September 1944:
Undergoes hull repairs.
6 September 1944:
Departs Kure.
8 September 1944:
At 1100, RYOEI MARU departs Moji for Singapore in convoy HI-75 consisting of oilers NICHIEI, YUHO, TOHO (1944), SERIA, AMATO and MANEI MARUs and passenger liner ASAMA MARU, cargo-passenger SAIGON MARU and flying boat tender AKITSUSHIMA escorted by escort carrier SHINYO, kaibokan KANJU, MANJU and MIYAKE and DesDiv 30’s YUZUKI and UZUKI. Arrives at Imari later this day. Departs later that same day.
12 September 1944:
In the morning, SAIGON MARU, YUZUKI and KANJU are detached for the China coast. They later rejoin at Takao.
13 September 1944:
At 1400, arrives at Takao.
14 September 1944:
The convoy is increased by the addition of oilers FUJISAN MARU (1944), KUROSHIO and TAIHO MARUs, torpedo boat HIYODORI and kaibokan CD-28. At 1630, the convoy departs Takao. Soon thereafter, AMATO MARU, and at 1900, YUHO MARU develop engine problems and are detached.
16 September 1944:
At 2330, KANJU, suffering rudder problems, collides with SERIA MARU, but there is little damage. Kaibokan KURAHASHI departs Yulin, Hainan Island, China to reinforce the escort of the convoy.
17 September 1944:
At 1000, SAIGON MARU and AKITSUSHIMA with escorts YUZUKI and UZUKI are detached from HI-75 and head for Manila. Enroute, SAIGON MARU carrying 700 mines and 100 depth-charges is sunk by Cdr (later Rear Admiral) Reuben T. Whitaker's USS FLASHER (SS-249) at 14-20N, 120-05E. Six crewmen are KIA. DesDiv 30’s YUZUKI and UZUKI hunt for the submarine, but Whitaker evades. YUZUKI and UZUKI rescue SAIGON MARU’s survivors, not including Captain Kameyama Minegoro (44). He is promoted Rear Admiral, posthumously.
18 September 1944:
At 1040, kaibokan KURAHASHI joins the escort.
19 September 1944:
At 1500, AMATO MARU rejoins the convoy.
20 September 1944:
During the day, NICHIEI, KUROSHIO, TAIHO and FUJISAN (1944) MARUs and carrier SHINYO all suffer engine or rudder problems, but the convoy remains intact.
22 September 1944:
Kaibokan CD-28 falls behind due to rudder problems. At 1300, arrives at Singapore. At 1840 CD-28 solves the rudder problems.
23 September 1944:
CD-28 arrives at Singapore.
24 September 1944:
Departs Singapore and arrives at Muntok, Bangka Island, Netherlands East Indies (now Indonesia) later that day.
26 September 1944:
Muntok. Replenishes heavy oil from auxiliary oiler MANEI MARU and auxiliary oiler YUHO MARU transfers some of her cargo.

27 September 1944:
Replenishes heavy oil from auxiliary oiler MANEI MARU.
30 September 1944:
Departs Muntok. Arrives back at Singapore the same day.
2 October 1944:
At 1700, RYOEI MARU departs Singapore for Moji in convoy HI-76 consisting of oilers IJA OILER NICHINAN (5175 GRT) MARU and, IJN oilers FUJISAN (1944), KUROSHIO, TARAKAN and TOHO (1944) MARUs, ex-seaplane tender KIMIKAWA MARU and cargo ship TEIHOKU MARU (ex-French PERSEE) escorted by escort carrier SHINYO and kaibokan KANJU, MANJU, MIYAKE, KURAHASHI and CD-28 and torpedo boat HIYODORI.
8 October 1944:
South China Sea. At 0100, LtCdr Henry D. Sturr’s (USNA ’33) USS BECUNA (SS-319) torpedoes and damages KIMIKAWA MARU at 14-12N, 115-53E. KIMIKAWA MARU is hit by two torpedoes, but remains navigable. She is detached from the convoy and heads for Manila escorted by HIYODORI and CD-28. At 0248 kaibokan MANJU carries out an anti submarine sweep
10 October 1944:
After receiving reports of an American task force striking Okinawa, convoy HI-76 diverts to Samah (Sanya) Hainan Island, China. IJN oiler TARAKAN MARU discovers cracks in her hull. IJN oilers TARAKAN and NICHIEI MARUs detach and head towards Yulin escorted by kaibokan MIYAKE and MANJU.
11 October 1944:
At 1500, arrives at Samah.
16 October 1944:
At 0745, departs Samah. That same day, headquarters, Combined Fleet, assigns RYOEI MARU to Vice Admiral Kurita Takeo's (38)(former CO of KONGO) First Striking Force's 1st Supply Force with IJN oilers ITSUKUSHIMA MARU, NICHIEI, YUHO, OMUROSAN,and MANEI (BANEI) MARUs and kaibokan CHIBURI, CD-19 and CD-27, minelayer YURISHIMA and minesweeper W-34.
17 October 1944:
At 1057 the convoy reverses its course. RYOEI MARU is detached from convoy HI-76 and heads for Mako escorted by kaibokan MANJU and MIYAKE. They arrive at Takao later this day.
20 October 1944:
Vice Admiral Shima Kiyohide's (39) (former CO of OI) Fifth Fleet arrives at Mako consisting of CruDiv 21’s NACHI and ASHIGARA and Rear Admiral (later Vice Admiral) Kimura Masatomi's (41) (former CO of SUZUYA) DesRon 1's light cruiser ABUKUMA and DesDiv 7's AKEBONO, KASUMI and USHIO, DesDiv 18's SHIRANUI and Des21's WAKABA, HATSUSHIMO and HATSUHARU.
At 0930 at Mako refuels destroyer HATSUHARU and from 1000 refuels all ships of the Second Squadron.
21 October 1944:
At 1100 at Mako refuels destroyer USHIO. At 1600, Shima’s Fifth Fleet departs Mako. RYOEI MARU remains at Mako.
31 October 1944:
Departs Mako and arrives of Takao later this day. At 1600 convoy HI-79 bound for Singapore consisting of IJN transport ARIMASAN MARU and IJN oilers TENEI and MATSUSHIMA MARUs escorted by light cruiser KASHI, with Rear Admiral Yoshitomi Setsuzo (39), CINC, 5th Escort Group embarked, kaibokan CD-17, NOMI and UKURU, minesweeper W-21 and minelayer NIIZAKI departs Takao. Late afternoon RYOEI MARU with IJN oiler KUROSHIO MARU and kaibokan MANJU joins convoy HI-79
2 November 1944:
E of Hainan. At 1432, the convoy is bombed by one Consolidated B-24 "Liberator" heavy bomber from high altitude. No damage is done to the convoy.
4 November 1944:
At 2322, the convoy’s second ship falls behind due to a rudder failure. Kaibokan UKURU is dispatched to assist and escort her.
5 November 1944:
At 1030 rudder failure is repaired and subsequently the second ship and kaibokan UKURU rejoin the convoy.
8 November 1944:
At 0640 IJN transport ARIMASAN MARU falls behind due to a rudder failure. Kaibokan UKURU is dispatched to assist and escort her. At 0830 rudder failure is repaired and subsequently the IJN transport ARIMASAN MARU and kaibokan UKURU rejoin the convoy.
At 1230 arrives off Singapore.
9 November 1944:
Departs off Singapore anchorage and arrives at Singapore later that day.
17 November 1944:
RYOEI MARU departs Singapore in convoy HI-80 also consisting of IJN oilers TENEI, MATSUSHIMA, MUNAKATA, KAIHO and KUROSHIO MARUs, IJA oiler NICHINAN MARU (5175 GT) and IJN transport ARIMASAN MARU escorted by light cruiser KASHII (F), kaibokan MANJU, UKURU, NOMI, KASADO, MIYAKE, CD-17 and minelayer NIIZAKI.
20 November 1944:
At 0600, CD-23 and CD-51 join the convoy from St. Jacques, French Indochina (now Vung Tau, Vietnam). At 1240, CD-17 is detached for Saigon.
21 November 1944:
At 0235 due to poor visibility the first ship, IJA oiler NICHINAN MARU (5175 GT), kaibokan CD-23, CD-51, MIYAKE and MANJU are separated from the convoy. At 1155 they rejoin the convoy.

22 November 1944:
At 0103 due to poor visibility the eighth ship, kaibokan CD-51 and MANJU are seperated from the convoy. At 0830 they rejoin the convoy. At 1531 due to a mechanical failure IJA oiler NICHINAN MARU (5175 GRT) falls behind. Kaibokan UKURU is dispatched to escort her. At 1815 they rejoin the convoy.

23 November 1944:
At 1150 due to a mechanical failure IJA oiler NICHINAN MARU (5175 GRT) falls behind. Kaibokan UKURU is dispatched to escort her. At 1204 kaibokan MANJU replaces kaibokan UKURU. UKURU thereafter rejoins the convoy. Later this day kaibokan CD-51 detaches and joins IJA oiler NICHINAN MARU (5175 GRT) and kaibokan MANJU.
24 November 1944:
A Consolidated B-24 "Liberator" heavy bomber attacks the convoy at 16-34N, 108-21E, but is driven off without inflicting damage to the convoy.
IJA oiler NICHINAN MARU (5175 GRT) and kaibokan MANJU and CD-51 arrive at Van Fong Bay, French Indochina (now Vinh Van Phong, Vietnam).
25 November 1944:
At 1903 kaibokan UKURU’s rudder fails. At 2258 UKURU’s rudder failure is recovered.
26 November 1944:
Kaibokan CD-51 rejoins the convoy.
28 November 1944:
At 0930 detaches with IJN transport ARIMASAN MARU and escort minelayer NIIZAKI for Takao. NIIZAKI detaches soon thereafter for Mako. Arrives with IJN transport ARIMASAN MARU at Takao later that same day.
9 December 1944:
RYOEI MARU departs Takao in convoy TASA-18 consisting of IJN tankers AMATO, ENKI and DAIETSU MARUs and TAMON MARU No. 15 escorted by kaibokan CD-14, CD-16, CD-46 and minesweeper W-101. At 2000 arrives with the convoy off the coast of Anping, Formosa (now Taiwan) and stays there.
10 December 1944:
At 0000 departs temporary anchorage off the coast off Anping with the convoy. At 1000 IJN oiler TAMON MARU No. 15 has an engine breakdown and is detached with minesweeper W-101 and IJN oiler ENKI MARU for Hong Kong.
13 December 1944:
Arrives at Yulin.
14 December 1944:
Departs Yulin in convoy TASA-18.
15 December 1944:
At 1845 arrives with the convoy at Van Fong Bay and stays there during the night.
16 December 1944:
At 0730 departs Phan Thiet Bay. At 1530 calls at St. Jacques. At 1550 the convoy is atttacked by one large enemy aircraft at 233° and 10 nautical miles of the Padaran Lighthouse, French Indochina (now Muin Dinh Lighthouse, Vietnam). At 2110 arrives at Phan Thiet Bay, French Indochina (now Vinh Phan Thiet, Vietnam) and stays there during the night.
17 December 1944:
At 1530, arrives at St Jacques, Indochina.
17 ~ 18 December 1944:
Embarks 107 passengers.
18 December 1944:
Departs Saigon in convoy SASHI-38 also consisting of IJN oiler AMATO MARU. Unable to meet with escorts minelayer NIIZAKI and patroal boat PB-102 (ex-USS STEWART, DD-224).
21 December 1944:
Arrives still in convoy at Singapore.
26 December 1944:
At 1158, RYOEI MARU departs Singapore for Moji in convoy HI-84 consisting of IJA transport AWA MARU, IJN storeship IKUTAGAWA MARU and IJN oilers AKASHI, AMATO and MIRI MARUs and oiler TOA MARU (1944) and one other unidentified ship escorted by escort carrier KAIYO, kaibokan OKINAWA and CD-63 and patrol boat P-102 (ex-USS STEWART, DD-224).
29 December 1944:
At 1157, HI-84 arrives at Cape St. Jacques and departs at 1625 the same day.
30 December 1944:
South China Sea. HI-84 passes CarDiv 4's hybrid battleship/carriers ISE and HYUGA, cruisers OYODO and ASHIGARA, DesDiv 2's ASASHIMO and DesDiv 18's KASUMI that are enroute south from Camranh Bay. Later that day, HI-84 arrives at Van Phong Bay, Indochina.
31 December 1944:
At 0745, HI-84 departs Van Phong Bay. Soon after departure, LtCdr Otis R. Cole's (USNA ’36) USS DACE (SS-247) fires three torpedoes at KAIYO, but gets no hits. There is no counterattack, as the convoy seems unaware of the attack. At 1804, HI-84 arrives at Quinhon Bay, French Indochina (now Quy Nhon Bay, Vietnam).
1 January 1945:
Departs Quinhon Bay.
2 January 1945:
At 0105, arrives at Tourane, French Indochina (now Da Nang, Vietnam). Departs later this day.
3 January 1945:
S of Hainan Island. MIRI MARU strikes a mine and her engine room floods. She is left behind, but manages to reach Hong Kong.
4 January 1945:
Arrives at East Dragon Point ( west of Waglan and Tung Lung Chau, Hong Kong and east of east coast of Hong Kong Island), Hong Kong. Departs later that day and arrives at Nanao Island, China later this day. Departs Nanao Island later that same day.
5 January 1945:
At 1840, convoy HI-84 arrives at the Hong Kong area and departs at 1937.
9 January 1945:
Arrives at Chusan (now Zhoushan) Island, China.
10 January 1945:
Departs Chusan Island.
13 January 1945:
At 1725, arrives at Moji.
14 January 1945:
Arrives at Kure.
18 January 1945:
Departs Kure.
19 January 1945:
Arrives at Aioi. Enters a dock of Harima Zosensho K.K for hull repair and weapon expansion. Additional AA weapons are fitted.
28 January 1945:
Departs Aioi.
29 January 1945:
Arrives at Kure.
1 February 1945:
Departs Kure.
7 February 1945:
At 0600, RYOEI MARU, in ballast, departs Moji for Singapore in convoy HI-97 consisting of empty IJN tanker PALEMBANG MARU escorted by kaibokan CD-1, CD-130 and CD-134.
15 February 1945:
At 2200, arrives at Qui Sande Bay, French Indochina (now Vietnam).
16 February 1945:
At 0700, departs at Qui Sande Bay.
20 February 1945:
Off Singapore buoy No. 5, lightly damaged by a mine. Arrives at Singapore later that day.
27 February 1945:
At 1500, RYOEI MARU departs Singapore for Moji in convoy HI-98 consisting of IJN tanker PALEMBANG MARU escorted by kaibokan CD-69 and CD-134.
3 March 1945:
At 0730, convoy HI-98 arrives at Cap St. Jacques, Indochina. Kaibokan CD-1 and CD-130 join the escort. At 0930, the convoy departs.
4 March 1945:
Off Cape Varella, Indochina. At 0930, LtCdr Benjamin C. Jarvis' (USNA ’39) USS BAYA (SS-318) fires six torpedoes at PALEMBANG and RYOEI MARUs. Those aimed at RYOEI MARU miss, but two torpedoes hit PALEMBANG MARU carrying gasoline, copper & crude rubber, amidships. She explodes and sinks immediately at 12-52N, 103-30E. Nine passengers, 59 gunners and 67 crewmen are KIA. CD-69 and CD-134 remain behind and drop 47 depth-charges, but do not damage USS BAYA. At 2300, the convoy anchors at Tourane.
5 March 1945:
At 0600, CD-69 and CD-134 arrive at Tourane and rejoin the convoy that departs at 0700 for Samah, Hainan Island. At 1110, at 16-46N, 108-41E Reserve LtCdr H. S. Simpson's USS BASHAW (SS-241) fires six torpedoes at RYOEI MARU of which two hit. One near the fuel storage in the center of the starboard side and one in front of the engine room. At 1228 Simpson sees one end of the RYOEI MARU rise out of the water and sees only three of the four escorts. At 1321 sees three escorts departing in column in the direction of Yulin. At 1356 the escorts discover the USS BASHAW. The last escort in the column opens fire with its forward gun. However USS BASHAW is out of range. USS BASHAW chases the escorts but is unable to catch up with them before they reach Yulin. At 1650 sees the bow wreckage of the RYOEI MARU and radar shows one escort in the area. At 1735 this escort can’t be seen through the periscope. Simpson judges that 80 ~ 100 feet of wreckage is sticking out of the water and is firmly anchored on the bottom. At 1952 fires a torpedo but misses. At 2003 fires another torpedo which hits but seems to have no effect. At 2030 the pip disappears from the radar screen. Returns to firing point and discovers that the remaining wreckage has disappeared. 19 crewmen, 19 gunners and nine passengers are KIA.
10 May 1945:
Removed from the Navy List.

Authors’ Note:
[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] IJN auxiliary ships were divided two categories. (Ko) category with an IJN Captain as supervisor aboard and (Otsu) category without.
[3] Australian diver/photojournalist Kevin Denlay reports that in 2004 divers from M/V EMPRESS out of Singapore located the bow section of IKI laying on its starboard side in about 50m/165ft of water. However, although they searched nearby, they did not find the rest of the wreck.
[4] The Japanese used the phonetic Katakana syllabary to describe place names for most locations outside of Japanese territory and China. In most cases these Katakana names were phonetic representations of original English, Spanish, Dutch, Malay and Indonesian names. In some cases, the Bahasa Indonesia rendering of the name was different from the Colonial Dutch rendering of the same name. After Indonesia's independence from the Netherlands there were a number of name changes with Dutch and Anglo names excised. Thus, the noted locations given in the TROM are speculative at best.
The authors wish to acknowledge the assistance of Erich Muehlthaler of Germany in this task. Grateful thanks also to Mr. Gilbert Casse of France for additional assistance and Berend van der Wal of Netherlands for updates in Revision 6. Thanks also go to Gengoro S. Toda of Japan.
- Bob Hackett and Peter Cundall.

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