(Oiler by Takeshi Yuki scanned from "Color Paintings
of Japanese Warships")
IJN RYOEI MARU: Tabular Record of Movement
© 2008-2015 Bob Hackett and Peter Cundall.
20 September 1943:
Aioi. Laid down by Harima Shipbuilding as a 10,006-ton Standard Merchant 1TL tanker for Nitto Kisen K. K., Tokyo.
21 January 1943:
Launched and named RYOEI MARU.
29 February 1944:
Completed and requisitioned by the IJN as a general requisitioned tanker (B-AO).
1 March 1944:
4 March 1944:
Arrives at Iwakuni.
11 March 1944:
12 March 1944:
Arrives at Amagasaki.
15 March 1944:
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 consisting of OTORISAN, KACHIDOKI (ex-PRESIDENT HARRISON), ASANAGI, TARAKAN and TENSHIN MARUs and six unidentified ships escorted by destroyer HARUKAZE.
24 March 1944:
The convoy arrives at Takao. 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 consisting of RYOEI, OTORISAN, KACHIDOKI (ex-PRESIDENT HARRISON), ASANAGI, TARAKAN and TENSHIN MARUs 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 consisting of tankers ITSUKUSHIMA, OTOWASAN and OMUROSAN MARUs, IJA landing craft depot ships SHINSHU and MAYASAN MARUs
and three unidentified ships (likely tankers SHINCHO and ZUIHO MARUs and another) 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.
8 April 1944:
At 1000, departs Takao.
12 April 1944:
At 1930, arrives at Camranh Bay.
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 consisting of tankers ITSUKUSHIMA, OMUROSAN, OTOWASAN and probably ZUIHO MARUs, Army Landing craft depot ships SHINSHU and
MAYASAN MARUs escorted by escort carrier KAIYO and kaibokan IKI, ETOROFU, SHIMUSHU, CD-8 and CD-9.
24 April 1944:
E of Saigon. 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 again 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 (Ko) category. Her home port is Kure. 
10 May 1944:
11 May 1944:
Arrives at Moji.
13 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, tankers KYOKUHO and OTOWASAN MARUs 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.
14 May 1944:
Assigned to Combined Fleet No. 1 Supply Group.
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, Borneo. 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.
27 May 1944:
At 2000, arrives at Singapore.
1 June 1944:
Departs Singapore with tanker ASANAGI MARU and in the Bangka Straits meets up with minesweeper W-101 that escorts the ships.
5 June 1944:
At 0800 off Laut Is W-101 is detached. Later that day the tankers arrives at Balikpapan.
10 June 1944:
21 June 1944:
NE of Panay Island, Philippines. Departs Cabugao Bay, on the S coast of Catanduanes Island. 
25 June 1944:
Arrives at Guimaras.
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.
2 July 1944:
Arrives at Kure.
3 July 1944:
Repairs are begun.
4 July 1944:
Kure. RYOEI MARU arrives alongside NICHIEI MARU to take most of the balance of her cargo.
17 July 1944:
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.
26 July 1944:
Arrives at Manila.
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.
1 August 1944:
At 1539, arrives at Singapore.
10 August 1944:
At 0800, RYOEI MARU departs Singapore for Kure in the "Nichiei Maru” convoy consisting of oilers NICHIEI and OKIGAWA MARUs escorted by DesDiv 30 and kaibokan MANJU.
11 August 1944:
At 1740, OKIGAWA MARU and SATSUKI are detached and return to Singapore.
17 August 1944:
At 1350, arrives at Mako. Departs at 1750.
21 August 1944:
Arrives at 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 and heavy cruiser SUZUYA.
23 August 1944:
Arrives at Hashirajima. Tows destroyer SUZUTSUKI and departs later that day, arriving at Kure that evening.
24 August~5 September 1944:
Undergoes hull repairs.
6 September 1944:
8 September 1944:
At 1100, RYOEI MARU departs Moji for Singapore in convoy HI-75 consisting of oilers NICHIEI, YUHO, TOHO (1944 built), 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.
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.
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 MARUs and carrier SHINYO all suffer engine or rudder problems, but the convoy remains intact.
22 September 1944:
At 1300, arrives at Singapore.
24 September 1944:
Departs Singapore and arrives at Muntok, Bangka Island later that day.
26 and 27 September 1944:
Muntok. Receives fuel from 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 NICHIEI, NICHINAN, FUJISAN, KUROSHIO, TARAKAN and TOHO MARUs, ex-seaplane tender KIMIKAWA MARU and cargo ship TEIHOKU MARU (ex-French PERSEE) escorted by escort carrier SHINYO and kaibokan DAITO, KANJU,MANJU, MIYAKE, KURAHASHI, CD-9 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.
10 October 1944:
After receiving reports of an American task force striking Okinawa, convoy HI-76 diverts to Samah, Hainan Island.
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 oilers TSUKUSHIMA MARU, NICHEI, YUHO, OMUROSAN,and BANEI MARUs and kaibokan CHIBURI, CD-19 and CD-27, minelayer YURISHIMA and minesweeper W-34.
17 October 1944:
RYOEI MARU is detached from convoy HI-76 and heads for Mako escorted by kaibokan MANJU and MIYAKE.
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, RYOEI MARU arrives at Mako and refuels Shima’s fleet.
21 October 1944:
At 1600, Shima’s Fifth Fleet departs Mako. RYOEI MARU remains at Mako until at least 27 October, then departs for Takao.
30 October 1944:
Takao. RYOEI MARU, tanker KUROSHIO MARU and kaibokan MANJU join convoy HI-79 consisting of transport ARIMASAN MARU and tankers TENEI and MATSUSHIMA MARUs escorted by light cruiser KASHI, kaibokan NOMI and minelayer NIIZAKI.
9 November 1944:
Arrives at Singapore.
17 November 1944:
RYOEI MARU departs Singapore in convoy HI-80 consisting of TENEI, MATSUSHIMA, MUNAKATA, ARIMASAN, KUROSHIO, NICHINAN and KAIHO MARUs escorted by light cruiser KASHII (F), kaibokan MANJU, UKURU, NOMI, KASADO, MIYAKE, CD-17, CD-23 and CD-51 and minelayer NIIZAKI.
20 November 1944:
At 1240, CD-17 is detached for Saigon.
27 November 1944:
At 0930, RYOEI and ARIMASAN MARUs are detached for Takao escorted by minelayer NIIZAKI.
28 November 1944:
Arrives at Takao.
9 December 1944:
RYOEI MARU departs Takao in convoy TASA-18 consisting of tankers AMATO, ENKI and DAIETSU MARUs and TAMON MARU No. 15 escorted by kaibokan CD-14, CD-16, CD-46 and minesweeper W-101.
10 December 1944:
TAMON MARU No. 15 has an engine breakdown and is detached with minesweeper W-101 for Hong Kong.
13 December 1944:
Arrives at Yulin.
17 December 1944:
At 1530, arrives at St Jacques, Indochina.
18 December 1944:
21 December 1944:
Arrives at Singapore.
26 December 1944:
At 1158, RYOEI MARU departs Singapore for Moji in convoy HI-84 consisting of transport AWA MARU, oilers TOA and MIRI MARUs and four other unidentified ships escorted by escort carrier KAIYO, kaibokan OKINAWA, CD-27 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 (near Saigon) 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 Binhoang Bay, Indochina.
31 December 1944:
At 0745, HI-84 departs Binhoang 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, Indochina.
1 January 1945:
2 January 1945:
At 0105, arrives at Shiran Bay, Indochina.
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.
5 January 1945:
At 1840, convoy HI-84 arrives at the Hong Kong area
and departs at 1937.
9 January 1945:
Arrives at Chusan Retto (archipelago), E of Shanghai.
10 January 1945:
Departs Chusan Retto.
13 January 1945:
At 1725, arrives at Moji.
14 January 1945:
Arrives at Kure.
18 January 1945:
19 January 1945:
Arrives at Aioi. Repairs at Harima Zosen commence.
Additional AA weapons are also fitted.
28 January 1945:
29 January 1945:
Arrives at Kure.
7 February 1945:
At 0600, RYOEI MARU, in ballast, departs Moji for Singapore in convoy HI-97 consisting of empty tanker PALEMBANG MARU escorted by kaibokan CD-1, CD-130 and CD-134.
15 February 1945:
At 2200, arrives at Qui Sande Bay, Indochina.
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 tanker PALEMBANG MARU escorted by kaibokan CD-69, CD-130 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, RYOEI MARU is torpedoed by Reserve LtCdr H. S. Simpson's USS BASHAW (SS-241) and sinks within the hour at 16-46N, 108-41E. 19 crewmen, 19 gunners and nine passengers are KIA.
10 May 1945:
Removed from the Navy List.
 IJN auxiliary ships were divided two categories. (Ko) category with an IJN Captain as supervisor aboard and (Otsu) category without.
 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.
 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.
- Bob Hackett and Peter Cundall.
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