||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (May 2010)|
Operation Hailstone (known in Japan as Japanese: トラック島空襲 Torakku-tō Kūshū, lit. "the airstrike on Truk Island") was a massive naval air and surface attack launched on February 16-17, 1944, during World War II by the United States Navy against the Japanese naval and air base at Truk in the Caroline Islands, a pre-war Japanese territory.
Truk was a major Japanese logistical base as well as the operating "home" base for the Imperial Japanese Navy's Combined Fleet. Some have described it as the Japanese equivalent of the US Navy's Pearl Harbor. The atoll was the only major Japanese airbase within range of the Marshall Islands and was a significant source of support for Japanese garrisons located on islands and atolls throughout the central and south Pacific. The base was the key logistical and operational hub supporting Japan's perimeter defenses in the central and south Pacific.
To ensure air and naval superiority for the upcoming invasion of Eniwetok Admiral Raymond Spruance ordered an attack on Truk. Vice Admiral Marc A. Mitscher's Task Force 58 had five fleet carriers (USS Enterprise (CV-6), USS Yorktown (CV-10), USS Essex (CV-9), USS Intrepid (CV-11), and USS Bunker Hill (CV-17)) and four light carriers (USS Belleau Wood (CVL-24), USS Cabot (CVL-28), USS Monterey (CVL-26), and USS Cowpens (CVL-25)), embarking more than 500 planes. Supporting the carriers was a large fleet of seven battleships, and numerous cruisers, destroyers, submarines, and other support ships.[page needed]
Fearing that the base was becoming too vulnerable, the Japanese had relocated the aircraft carriers, battleships, and heavy cruisers of the Combined Fleet to Palau a week earlier. However, numerous smaller warships and merchant ships remained in and around the anchorage and several hundred aircraft were stationed at the atoll's airfields.
The U.S. attack involved a combination of airstrikes, surface ship actions, and submarine attacks over two days and appeared to take the Japanese completely by surprise. Several daylight, along with nighttime, airstrikes employed fighters, dive bombers, and torpedo aircraft in attacks on Japanese airfields, aircraft, shore installations, and ships in and around the Truk anchorage. A force of U.S. surface ships and submarines guarded possible exit routes from the island's anchorage to attack any Japanese ships that tried to escape from the airstrikes.
In total the attack sank three Japanese light cruisers (Agano, Katori, and Naka), four destroyers (Oite, Fumizuki, Maikaze, and Tachikaze), three auxiliary cruisers (Akagi Maru, Aikoku Maru, Kiyosumi Maru), two submarine tenders (Heian Maru, Rio de Janeiro Maru), three other smaller warships (including submarine chasers Ch-24 and Shonan Maru 15), aircraft transport Fujikawa Maru, and 32 merchant ships. Some of the ships were destroyed in the anchorage and some in the area surrounding Truk lagoon. Many of the merchant ships were loaded with reinforcements and supplies for Japanese garrisons in the central Pacific area. Very few of the troops aboard the sunken ships survived and little of their cargoes were recovered. (Lindeman, 2005)
Maikaze, along with several support ships, was sunk by U.S. surface ships while trying to escape from the Truk anchorage. The survivors of the sunken Japanese ships reportedly refused rescue efforts by the U.S. ships.[page needed] The cruiser Agano, a veteran of the Raid on Rabaul and which was already en route to Japan when the attack began, was sunk by a U.S. submarine, the USS Skate (SS-305). Oite rescued 523 survivors from the Agano and returned to Truk lagoon to assist in its defense with her anti-aircraft guns. She was sunk soon after by air attack with the Agano survivors still on board, killing all of them and all but 20 of the Oite's crew.
Over 250 Japanese aircraft were destroyed, mostly on the ground. Many of the aircraft were in various states of assembly, having just arrived from Japan in disassembled form aboard cargo ships. Very few of the assembled aircraft were able to take off in response to the U.S. attack. Several Japanese aircraft that did take off were claimed destroyed by U.S. fighters or gunners on the U.S. bombers and torpedo planes.
The U.S. lost twenty-five aircraft, mainly due to the intense anti-aircraft fire from Truk's defenses. About 16 U.S. aircrew were rescued by submarine or amphibious aircraft (several Japanese, whose crew took them prisoner). A nighttime torpedo attack by a Japanese aircraft from either Rabaul or Saipan damaged the Intrepid and killed 11 of her crew, forcing her to return to Pearl Harbor and later, San Francisco for repairs. She returned to duty in June, 1944. Another Japanese air attack slightly damaged the battleship USS Iowa (BB-61) with a bomb hit.[page needed]
An aerial view of the airstrike at Truk can be seen in the U.S. Navy film The Fighting Lady.
In his autobiography Baa Baa Black Sheep, U.S. Marine Corps ace pilot Gregory "Pappy" Boyington describes his experience as a prisoner of war on the ground at Truk during the raid.
The attacks for the most part ended Truk as a major threat to Allied operations in the central Pacific; the Japanese garrison on Eniwetok was denied any realistic hope of reinforcement and support during the invasion that began on February 18, 1944, greatly assisting U.S. forces in their conquest of that island.
The Japanese later relocated about 100 of their remaining aircraft from Rabaul to Truk. These aircraft were attacked by U.S. carrier forces in another attack on April 29–30, 1944 which destroyed most of them. The U.S. aircraft dropped 92 bombs over a 29 minute period to destroy the Japanese planes. The April 1944 strikes found no shipping in Truk lagoon and were the last major attacks on Truk during the war.
Truk was isolated by Allied (primarily U.S.) forces as they continued their advance towards Japan by invading other Pacific islands such as Guam, Saipan, Palau, and Iwo Jima. Cut off, the Japanese forces on Truk, like on other central Pacific islands, ran low on food and faced starvation before Japan surrendered in August 1945. (Stewart, 1986)
Truk IJN Anchorage Evacuation Log Book 
Dec 7th, 1943 Truk -> Kure
Dec 12th, 1943 Truk -> Yokosuka
Jan 19th, 1944 Truk -> Saipan
Jan 19th, 1944 Truk -> Rabaul
Jan 20th, 1944 Truk -> Ponape
Ogura Maru No. 3.
Jan 24th Truk -> Eniwetok
Jan 27th Truk -> Yokosuka (convoy No. 4127)
auxiliary subchaser Shonan Maru No. 8
Yoshida Maru No. 3
Jan 28th Truk -> Rabaul
Feb 3rd, 1944 Rabaul -> Truk => Beppu
Feb 3rd, 1944 Yokosuka -> Truk
Feb 5th, 1944 Truk -> Davao
Feb 9th, 1944 Truk -> Saipan (convoy No. 7125)
Feb 12th, 1944 Truk -> Palau (convoy No. 7125)
auxiliary subchasers Takunan Maru No. 2
auxiliary subchasers Shonan Maru No. 5
fleet oiler Sata
tanker Hishi Maru No. 2
ammunition ship Nichiro Maru
cargo ship Kamikaze Maru
cargo ship Kitakami Maru
Feb 15th, 1944 Truk -> Japan
CL Agano, sunk 160 miles norh of Truk on Feb 16th
DD Oite, sunk while entering back Truk via North Pass with survivors from CL Agano on Feb 18th
subchaser Ch-28, sunk on Feb 16th
Feb 17th, 1944 Truk -> assist damaged Agano
CL Naka, sunk
Feb 18th, 1944 Truk -> Saipan
Feb 18th, 1944 Truk -> Palau
Feb 26th, 1944 Truk -> Palau
Feb 27th, 1944 in Truk
subchaser CH-38 complete battle-damage repairs
subchaser CH-37 complete battle-damage repairs
Feb 29th, 1944 -> Truk
Mar 6th, 1944 Truk -> Saipan (convoy 4304)
Mar 17th, 1944 Truk -> Saipan (convoy 4304)
sub tender Tsukushi Maru
April 27, 1944 Truk -> Palau
May 25, 1944 Truk -> Saipan
June 3, 1944 Truk -> Saipan
auxiliary sub chaser CHa-66
oiler Nitcho Maru
oiler Kyoei Maru
oiler Nanko Maru No. 1
13 other unidentified ships.
List of warships in Truk at the time of attack 
CL Agano (阿賀野) 6,652 tons, sunk on Feb 16th, 1944
CL Naka (那珂) 5,195 tons, departed to assist CL Agano and sunk 35 mile west of Truk on Feb 17th
CL Katori (香取) 5,890 tons, sunk 40 miles northwest of Truk on Feb 17th together with Maikaze and Shonan Maru #15, only Nowaki escaped
DD Akikaze (秋風) 峯風型 1,215 tons, escaped undamaged
DD Fumizuki (文月) 睦月型 1,315 tons, anchored in repair anchorage and sunk off west of lagoon on Feb 18th despite assistance from Matsukaze and Hakachi
DD Harusame (春雨) 白露型 1,685 tons, minor damage and later escorted damaged DD Shigure from Truk to Palau
DD Maikaze (舞風) 陽炎型 2,490 tons, sunk by gunfire northwest of Truk in convoy to Yokosuka on Feb 17th
DD Matsukaze (松風) 神風型 1,400 tons, assisted and attempted to tow DD Fumizuki, medium damaged
DD Nowaki (野分) 陽炎型 2,490 tons, undamaged
DD Oite (追風) 神風型 1,270 tons, sunk while entering Truk via North Pass with survivors from CL Agano on Feb 18th
DD/P34 Susuki (薄) 樅型 935 tons, escaped but later sunk in an unrelated event off repair anchorage
DD Shigure (時雨) 白露型 1,685 tons, damaged while departing Truk via North Channel to Palau on Feb 17th
DD Tachikaze (太刀風) 峯風型 1,215 tons, ran aground on Kuop Atoll on Feb 4th and later sunk in Operation Hailstone
auxiliary cruiser Akagi Maru (赤城丸) 7,367 tons, sunk north of Truk
auxiliary submarine tender Heian Maru (平安丸) 11,616 tons, sunk off repair anchorage
aircraft transport Fujikawa Maru (富士川丸) 6,938 tons, sunk off 4th fleet anchorage
repair ship Akashi (明石) 10,500 tons, damaged
seaplane tender Akitsushima (秋津洲) 4,650 tons, damaged
submarine chaser CH-24, 438 tons, sunk west of Truk
submarine chaser CH-28, 438 tons, departed Truk with destroyer Oite and cruiser Agano on 15th of Feb
submarine chaser CH-33, 438 tons, damaged
submarine chaser CHa-20, damaged
submarine chaser CH-29, 420 tons, sunk
auxiliary submarine chaser Shonan Maru #15 (第15昭南丸), sunk
submarine I-10 (伊10), 2,919 tons, damaged
submarine RO-36, 1,115 tons, damaged
submarine RO-42, 1,115 tons, undamaged
motor torpedo boat #10, 80 tons, sunk
cargo ship Sōya (宗谷) 3,800 tons, damaged
target ship Hakachi (波勝) 1,641 tons, damaged
List of merchant ships at the time of attack and other shipwrecks in Truk's Anchorage 
navy transport Aikoku Maru (爱国丸) 10,348 tons, sunk off 4th fleet anchorage
navy transport Kiyosumi Maru (清澄丸) 6,983 tons, sunk off repair anchorage
navy transport Rio de Janeiro Maru (りおで志゛やねろ丸) 9,627 tons, sunk off 6th fleet anchorage
navy transport Yamagiri Maru (山霧丸) 6,439 tons, carrying Yamato's 46 cm projectiles, sunk off combined fleet anchorage
navy transport/passenger/cargo ship Kensho Maru (乾祥丸) 4,861 tons, sunk off repair anchorage
navy transport/passenger/cargo ship Sankisan Maru (山鬼山丸) 4,776 tons, sunk off 6th fleet anchorage
navy transport Houki Maru (伯耆丸) 7,112 ton, sunk off 4th fleet anchorage
navy transport Reiyo Maru (麗洋丸) 5,446 tons,sunk off 4th fleet anchorage
navy transport/freighter Syoutan Maru (松丹丸) 1,999 tons, sunk off 4th fleet anchorage
navy water carrier/passenger/cargo ship Nippo Maru (日豊丸) 3,673 tons, sunk off 4th fleet anchorage
navy transport Taiho Maru (大邦丸) 2,829 tons,sunk off 6th fleet anchorage
navy transport Unkai Maru #6 (第六雲海丸), sunk off 6th fleet anchorage
navy transport/freighter Gosei Maru (五星丸) 1,931 tons, sunk sunk off 6th fleet anchorage
navy transport/freighter Hanakawa Maru (花川丸) 4,793 tons, sunk off Tol
navy transport/freighter Hokuyo Maru (北洋丸) 4,217 tons, sunk off 4th fleet anchorage
navy transport/freighter Momokawa Maru (桃川丸) 3,829 tons, sunk off 4th fleet anchorage
navy transport/freighter San Francisco Maru (桑港丸) 5,864 tons, sunk off 4th fleet anchorage
navy transport/freighter Unkai Maru #6(第六雲海丸) 3,188 tons, sunk off 6th fleet anchorage
navy transport Kikukawa Maru (菊川丸) 6,853 tons, accidentally sunk on Oct 7th, 1943
navy transport Saiko Maru (西江丸)? 5,385 tons,sunk on Feb 17th, 1944
navy hospital ship Ten'o Maru (天應丸) 6,067 tons, anchored next to Heian Maru, escaped
navy transport Zukai Maru (瑞海丸) 2,812 tons, escaped
navy transport Tatsuhane Maru (辰羽丸) 5,784 tons, escaped
freighter Katsuragsan Maru (葛城山丸) 2,428 tons, sunk on Jan 4th 1944 north east off Moen
freighter Matsutani Maru (松谷丸)? 1,999 tons
freighter Taikichi Maru (泰吉丸)?
freighter Hino Maru #2 (第二日野丸) 999 tons, sunk off off 6th fleet anchorage near Uman Island
freighter Seiko Maru (星光丸)? 5,386 tons, sunk
army transport Gyoten Maru (暁天丸) 6,865 tons, sunk by USS Tang off Truk on February 17, 1944
army transport Yubae Maru (夕映丸) 3,200 tons,sunk off 6th fleet anchorage
army transport/freighter Nagano Maru (長野丸) 3,810 tons, sunk off 4th fleet anchorage
fleet oiler Shinkoku Maru (神国丸) 10,020 tons, sunk off combined fleet anchorage
oil tanker Fujisan Maru (富士山丸) 9,524 tons, sunk south west off Moen
auxiliary oil tanker Houyou Maru (宝洋丸) 8,691 tons, sunk off repair anchorage
auxiliary oil tanker/passenger/cargo ship Amagisan Maru (天城山丸) 7,620 tons, sunk off 6th fleet anchorage
auxiliary oil tanker/whaler Tonan Maru #3 (第三図南丸) 19,209 tons, sunk off repair anchorage
auxiliary provision storeship Sapporo Maru (札幌丸), sunk on May 29, 1944 on west of lagoon
repair ship/cargo ship Urakami Maru, anchored next to Tenno Maru and Heian Maru, damaged
picket boat Kotohira Maru 30 tons, sunk on April 15, 1944
salvage tug Woshima (雄島) 812 tons, accidentally sunk in an explosion with Kikukawa Maru on Oct 7th,1943
salvage tug Futakami (二神) 600 tons, scuttled off repair anchorage postwar
- Morison 1961, p. 330 Deaths included 29 aircrew plus 11 crewmen on Intrepid. Aircraft losses included 12 fighters, 7 torpedo-bombers, and 6 dive-bombers.
- Morison 1961.
- Video: Castle Films Yanks Smash Truk (1944). Castle Films. 1944. Retrieved February 27, 2013.
- Morison 1961, p. 330 Number derived by summing the total crews of the 25 aircraft lost and subtracting the number (29) listed as killed.
Further reading 
- Bailey, Dan E. (1992). World War II: Wrecks of the Kwajalein and Truk Lagoons. North Valley Diver Publications. ISBN 0-911615-05-9.
- Brown, David (1990). Warship Losses of World War Two. Naval Institute Press. ISBN 1-55750-914-X.
- Brown, Herbert C. (2000). Hell at Tassafaronga. Ancient Mariners Pr. ISBN 0-9700721-4-7.-Firsthand account of Operation Hailstone by a crewmember of USS New Orleans.
- Cressman, Robert J. (2000). The official chronology of the U.S. Navy in World War II. Annapolis, Maryland: Naval Institute Press. ISBN 1-55750-149-1.
- D'Albas, Andrieu (1965). Death of a Navy: Japanese Naval Action in World War II. Devin-Adair Pub. ISBN 0-8159-5302-X.
- Ito, Masanori (1986 (reissue)). The End of the Imperial Japanese Navy. Jove. ISBN 0-515-08682-7.
- Lacroix, Eric; Linton Wells (1997). Japanese Cruisers of the Pacific War. Naval Institute Press. ISBN 0-87021-311-3.
- Lindemann, Klaus (2005). Hailstorm Over Truk Lagoon: Operations Against Truk by Carrier Task Force 58, 17 and 18 February 1944, and the Shipwrecks of World War II. Oregon, USA: Resource Publications. ISBN 1-59752-347-X.
- Morison, Samuel Eliot (1961). Aleutians, Gilberts and Marshalls, June 1942-April 1944, History of United States Naval Operations in World War II. Boston: Little, Brown and Company. ASIN B0007FBB8I.
- Peattie, Mark (1992). Nan'Yo: The Rise and Fall of the Japanese in Micronesia, 1885-1945 (Pacific Islands Monograph Series). University of Hawaii Press. ISBN 0-8248-1480-0.
- Stafford, Edward P.; Paul Stillwell (Introduction) (2002 (reissue)). The Big E: The Story of the USS Enterprise. Naval Institute Press. ISBN 1-55750-998-0.
- Stewart, William Herman (1986). Ghost Fleet of the Truk Lagoon: An Account of "Operation Hailstone", February, 1944. Pictorial Histories. ISBN 0-933126-66-2.
- Wright III, Burton. Eastern Mandates. The US Army Campaigns in World War II. United States Army Center of Military History.
- Tashirō Iwashige, The visual guide of Japanese wartime merchant marine, "Dainippon Kaiga". (Japan), May 2009. ISBN 978-4-499-22989-0
- Quest for Sunken Warships : "Operation Hailstone", 2007, documentary, Military Channel, last aired September 30, 2010, 4-5pm MDT.
|Wikimedia Commons has media related to: Operation Hailstone|
- Crowl, Philip A.; Edmund G. Love (1955). Seizure of the Gilberts and Marshalls. United States Army in World War II - The War in the Pacific. Office of the Chief of Military History, Department of the Army. CMH Pub 5-6. Retrieved 2007-01-23.
- Jeffery, Bill (2003). "War in Paradise: World War II sites in Truk Lagoon, Chuuk, Federated States of Micronesia". Chuuk Historic Preservation Office. Retrieved 2006-08-30.
- Jeffery, William (November 2006). "A CRM Approach in Investigating the Submerged World War II Sites in Chuuk Lagoon" (PDF). Micronesian Journal of the Humanities and Social Sciences, Volume 5. James Cook University, Townsville, Australia. Retrieved 2007-01-23.
- WW2DB: Attack on Truk
- Account of the operation from Enterprise website
- Moderately brief account of the attack
- TRUK LAGOON AREA STUDY