YUSOSEN!

YUSOSEN!

Stories and Battle Histories of the IJN's Fleet Oilers

28 August 2010

By Bob Hackett and Peter Cundall

Discussion & Questions

(Oiler by Takeshi Yuki scanned from "Color Paintings of Japanese Warships")

Oil was a key factor in the Empire of Japan's decision to go to war with America. After Japan occupied southern French Indochina in the summer of 1941, the United States, Great Britain and the Netherlands East Indies placed an embargo on all petroleum products into Japan.
Just before their attack on Pearl Harbor, Japan had only 49 merchant tankers of about 587,000 tons and the IJN had but nine slow fleet oilers. Despite its prewar stockpiling of two years of petroleum products, Japan had to rely on imports from its conquered South Asia territories for survival.
Like all navies, oil was the lifeblood of the IJN. As a result, the IJN requisitioned 77 merchant ships from their owners for conversion to auxiliary oilers.
During the war the Japanese employment of merchants ships was divided into three main administrative categories:
A = requisitioned and operated by the Japanese Army
B = requisitioned and operated by the Japanese Navy with civilian crew (captain often being Navy Reserve)
C = controlled and operated by Senpaku Un´eikai (Civilian Shipping Administration)
X = requisitioned by the IJN and converted into armed Naval Auxiliaries with IJN crews (gunboats, minesweepers, etc.)
Beside the above categories, there were many shared employments Army/Civilian (A/C) and Navy/Civilian (B/C). These ships were called Haitosen. Normally, this meant that the vessel on its outbound journey was under Army or Navy control carrying troops, military supplies, etc. and on its return voyage was carrying cargo for the benefit of the civilian owner of ship.
While used by the Army, the Haitosen also received Army transport numbers like Army requisitioned vessels (A). Employments by Army or Navy could also be expanded, meaning that the ship was used by Army/Navy for one full turn (outward and homeward voyage) or even a series of voyages.
This page will cover the activities of 132 fleet and coastal tankers - 70 merchant tanker auxiliaries, 18 Navy fleet oilers and 37 civilian merchant tankers in Japanese national service and six captured and one German vessel in Japanese service.
Two of the Navy fleet oilers also served in the seaplane tender role and four were designed as aviation gasoline tankers to resupply carriers underway at sea. The latter Yusosen were officially termed Kihatsuyu Umpankan. Two tankers were converted to escort carriers for the IJA while still on the ways. One of these also would have served as a tanker. Neither became operational.
Some ex-foreign vessels served as tankers, but documenation of their Japanese service for most is either sparse or non-existant.

Tabular Records of Movement (TROMs):

Auxiliary Fleet Oilers

(Classes link to specifications summaries)

GENYO MARU Class
Genyo Maru (revised 4/17/2010)

Itsukushima Maru (revised 10/3/09)) Kenyo Maru (revised 5/12/2010) Kokuyo Maru (revised 5/12/2010) Nichiei Maru (revised 4/24/2010)
Toei Maru (posted 3/29/2007)

KYOKUTO MARU Class
Kyokuto Maru (posted 7/27/2007)

Toa Maru (revised 4/24/2010)
Toho Maru (posted 7/27/2007)

FUJISAN MARU Class
Fujisan Maru(revised 4/24/2010)
NIPPON MARU Class
Nippon Maru (revised 5/12/2010)

Tatekawa Maru (revised 4/17/2010)

SHINKOKU MARU Class
Shinkoku Maru (revised 5/12/2010)
GOYO MARU Class
Goyo Maru (posted 3/28/2008)
HOYO MARU Class
Hoyo Maru (revised 4/17/2010)

Kaijo Maru No. 2 Go (posted 3/7/2009)

AKATSUKI MARU Class
Akatsuki Maru (posted 7/24/2010)
Akebono Maru (revised 6/12/2010)

TEIYO MARU Class
Teiyo Maru (revised 12/12/2009)

SAN RAMON MARU Class
San Ramon Maru (posted 11/8/2008)

San Clemente Maru (posted 8/23/2008)

SAN PEDRO MARU Class
San Pedro Maru (posted 12/27/2008)

San Luis Maru (revised 5/23/2009)
San Diego Maru (posted 11/15/2008)

OTOWASAN MARU Class
Omurosan Maru (posted 1/10/2009)
OGURA MARU No. 2 Class
Ogura Maru No. 2 (revised 4/30/10)
OGURA MARU No. 3 Class
Ogura Maru No. 3 (posted 1/17/2009)
KIRISHIMA MARU Class
Kirishima Maru (revised 4/30/10)

NISSHO MARU Class
Nissho Maru (revised 4/30/10)

KYOKUYO MARU Class
Kyokuyo Maru (revised 4/30/10)

TOEN MARU Class
Toen Maru (revised 4/17/2010)
TONAN MARU No. 2 Class
Tonan Maru No. 2 (revised 4/17/2010)
Tonan Maru No. 3 (revised 4/17/2010) HISHI MARU No. 2 Class
Hishi Maru No. 2 (revised 4/30/10)
MOJI MARU Class
Moji Maru (posted 7/5/2009)

KYOEI MARU Class
Kyoei Maru (posted 5/22/2010)
KYOEI MARUs
No. 2 Class
Kyoei Maru No. 2 (posted 7/3/2010)
Kyoei Maru No. 3 (posted 8/22/2009)
AZUMA MARU Class
Azuma Maru (posted 1/2/2010)
Arima Maru (posted 12/5/2009)

SHOYO MARU Class
Shoyo Maru (posted 2/13/2010)

KINREI MARU Class
Kinrei Maru (posted 4/10/2010)

JUKO MARU Class
Juko Maru (posted 6/26/2010)

KIYO MARU Class
Kiyo Maru (posted 6/26/2010)

KUMAGAWA MARU Class
Kumagawa Maru (posted 7/3/2010)

TERUKAWA MARU Class
Terukawa Maru (posted 7/10/2010)

HISHI MARU Class
Hishi Maru (posted 7/17/2010)

KORYU MARU Class
Koryu Maru (posted 7/31/2010)

STANDARD TANKER 1TL Class
Azusa Maru (posted 6/28/08)

Seiyo Maru (posted 8/1/09)
Miri Maru (posted 8/8/09)
Kyuei Maru (posted 10/10/09)
Ryoei Maru (posted 10/17/09)
Nampo Maru (posted 10/31/09)
Nippo Maru (posted 8/7/10)
Ominesan Maru (posted 8/14/10)
Okikawa Maru(posted 8/28/10)
Amatsu Maru Shimane Maru
STANDARD TANKER 1TM Class
Yuho Maru (revised 4/17/2010)

Tarakan Maru(posted 8/29/09)
Manei Maru (posted 10/24/09)
Ryuei Maru (posted 11/7/09)
Shimpo Maru (posted 11/14/09)
Asanagi Maru (posted 11/21/09)
Asashio Maru (posted 8/7/10)
Bokuei Maru (posted 8/21/10)
Eiho Maru
Eiyo Maru No. 2
STANDARD TANKER 2TE Class
Murotsu Maru (posted 9/5/09)

Naval Fleet Oilers

(Classes link to specifications summaries)

SHIRETOKO Class
Shiretoko (posted 9/14/2007)

Notoro (revised 5/29/2007)
Iro (revised 4/24/2010) Erimo(posted 12/14/2007) Tsurumi (revised 4/17/2010) Shiriya (revised 5/23/2009) Sata (revised 4/24/2010) Ondo (revised 5/23/2009) Hayatomo (revised 4/24/2010) Naruto (revised 4/24/2010)
KAMOI Class
Kamoi (posted 4/18/2006)
HAYASUI Class
Hayasui (posted 1/9/2010)
KAZAHAYA Class
Kazahaya (posted 2/6/2010)
SUNOSAKI Class
Sunosaki (posted 6/12/10)

Takasaki (posted 7/17/2010)

ASHIZURI Class
Ashizuri (posted 6/20/2009)
Shioya (posted 7/25/09)

HARIO Class
Hario (revised 6/26/2010))

Civilian Merchant Tankers in Japanese National Service

(Classes link to specifications summaries)

OTOWASAN MARU Class
Otowasan Maru(posted 9/12/2009)

EIYO MARU Class
Eiyo Maru (revised 1/12/2010)

CHIYODA MARU Class
Chiyoda Maru (posted 1/30/2010)

Chihaya Maru (posted 2/6/2010)

TONAN MARU Class
Tonan Maru
HOKKI MARU Class
Hokki Maru
STANDARD TANKER 1TL Class
Hakko Maru
Hakko Maru No. 2 Hashidate Maru Niyo Maru Isshin Maru Takane Maru

STANDARD TANKER 1TM Class
Jambi Maru
Sarawak Maru Palembang Maru Otorisan Maru Marifu Maru Yamamizu Maru No. 2 Nichinan Maru No. 2 Ariake Maru Tenshin Maru Zuiho Maru STANDARD TANKER 2TL Class
Jinei Maru
Seria Maru Mitsushima Maru Tenei Maru Arita Maru Tojo Maru Fujisan Maru Kaiho Maru Munakata Maru Akashi Maru Amato Maru Akane Maru Matsushima Maru Tatekawa Maru No. 2 Yamashio Maru

Captured and Foreign Vessels in Japanese Service as Tankers

(Ex-Countries link to specifications summaries)

Ex-American Vessel

Sanraku Maru

Ex-British Vessels

Choran Maru Enoshima Maru

German Vessel

Teikon Maru
Ex-Dutch Vessels

Ose Kyoko Maru Aiten Maru

Bibliography of Sources

About the Authors

Mr. Robert Hackett is a military historian and researcher. Retired from the United States Air Force and later from the aerospace industry, he resides in the United States.

Mr. Peter Cundall is a maritime historian and researcher who specializes in merchant ships. He resides in Australia.

Questions to the authors concerning these TROMs should be posted on the Discussion and Questions board.

GENYO MARU Class Genyo Maru (revised 4/17/2010) Itsukushima Maru (revised 10/3/09)) Kenyo Maru (revised 5/12/2010) Kokuyo Maru (revised 5/12/2010) Nichiei Maru (revised 4/24/2010) Toei Maru (posted 3/29/2007)	KYOKUTO MARU Class Kyokuto Maru (posted 7/27/2007) Toa Maru (revised 4/24/2010) Toho Maru (posted 7/27/2007)	FUJISAN MARU Class Fujisan Maru(revised 4/24/2010)	NIPPON MARU Class Nippon Maru (revised 5/12/2010) Tatekawa Maru (revised 4/17/2010)	SHINKOKU MARU Class Shinkoku Maru (revised 5/12/2010)	GOYO MARU Class Goyo Maru (posted 3/28/2008)	HOYO MARU Class Hoyo Maru (revised 4/17/2010) Kaijo Maru No. 2 Go (posted 3/7/2009)	AKATSUKI MARU Class Akatsuki Maru (posted 7/24/2010) Akebono Maru (revised 6/12/2010)
TEIYO MARU Class Teiyo Maru (revised 12/12/2009)	SAN RAMON MARU Class San Ramon Maru (posted 11/8/2008) San Clemente Maru (posted 8/23/2008)	SAN PEDRO MARU Class San Pedro Maru (posted 12/27/2008) San Luis Maru (revised 5/23/2009) San Diego Maru (posted 11/15/2008)	OTOWASAN MARU Class Omurosan Maru (posted 1/10/2009)	OGURA MARU No. 2 Class Ogura Maru No. 2 (revised 4/30/10)	OGURA MARU No. 3 Class Ogura Maru No. 3 (posted 1/17/2009)	KIRISHIMA MARU Class Kirishima Maru (revised 4/30/10)	NISSHO MARU Class Nissho Maru (revised 4/30/10)
KYOKUYO MARU Class Kyokuyo Maru (revised 4/30/10)	TOEN MARU Class Toen Maru (revised 4/17/2010)	TONAN MARU No. 2 Class Tonan Maru No. 2 (revised 4/17/2010) Tonan Maru No. 3 (revised 4/17/2010)	HISHI MARU No. 2 Class Hishi Maru No. 2 (revised 4/30/10)	MOJI MARU Class Moji Maru (posted 7/5/2009)	KYOEI MARU Class Kyoei Maru (posted 5/22/2010)	KYOEI MARUs No. 2 Class Kyoei Maru No. 2 (posted 7/3/2010) Kyoei Maru No. 3 (posted 8/22/2009)	AZUMA MARU Class Azuma Maru (posted 1/2/2010) Arima Maru (posted 12/5/2009)
SHOYO MARU Class Shoyo Maru (posted 2/13/2010)	KINREI MARU Class Kinrei Maru (posted 4/10/2010)	JUKO MARU Class Juko Maru (posted 6/26/2010)	KIYO MARU Class Kiyo Maru (posted 6/26/2010)	KUMAGAWA MARU Class Kumagawa Maru (posted 7/3/2010)	TERUKAWA MARU Class Terukawa Maru (posted 7/10/2010)	HISHI MARU Class Hishi Maru (posted 7/17/2010)	KORYU MARU Class Koryu Maru (posted 7/31/2010)
STANDARD TANKER 1TL Class Azusa Maru (posted 6/28/08) Seiyo Maru (posted 8/1/09) Miri Maru (posted 8/8/09) Kyuei Maru (posted 10/10/09) Ryoei Maru (posted 10/17/09) Nampo Maru (posted 10/31/09) Nippo Maru (posted 8/7/10) Ominesan Maru (posted 8/14/10) Okikawa Maru(posted 8/28/10) Amatsu Maru Shimane Maru	STANDARD TANKER 1TM Class Yuho Maru (revised 4/17/2010) Tarakan Maru(posted 8/29/09) Manei Maru (posted 10/24/09) Ryuei Maru (posted 11/7/09) Shimpo Maru (posted 11/14/09) Asanagi Maru (posted 11/21/09) Asashio Maru (posted 8/7/10) Bokuei Maru (posted 8/21/10) Eiho Maru Eiyo Maru No. 2	STANDARD TANKER 2TE Class Murotsu Maru (posted 9/5/09)