Operation Hailstone

Operation Hailstone
	Part of World War II, Pacific War
	; A Japanese freighter in Truk Atoll is hit by a torpedo dropped from a TBF Avenger from USS Enterprise during Operation Hailstone, February 17, 1944.
Date	February 17, 1944 – February 18, 1944
Location	Truk, Caroline Islands
Result	American victory, prevented the Japanese reinforcement of Eniwetok garrison, key Japanese warships avoided destruction
Belligerents
United States	Empire of Japan
Commanders and leaders
Marc A. Mitscher	Chuichi Hara
Strength
5 fleet carriers, ; 4 light carriers, ; 7 Battleships ; 45 other warships, ; 10 submarines, ; 589 planes	3 cruisers, ; 8 destroyers, ; 5 other warships, ; 50 merchant ships, ; 350 planes
Casualties and losses
1 aircraft carrier damaged, ; 1 battleship slightly damaged, ; 25 aircraft destroyed; 40 killed	3 cruisers, ; 4 destroyers, ; 3 auxiliary cruisers, ; 2 submarine tenders, ; 3 smaller warships, ; 32 merchant ships sunk, ; 270 aircraft destroyed

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 17-18, 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.

Background

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.

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 (Enterprise, Yorktown, Essex, Intrepid, and Bunker Hill) and four light carriers (Belleau Wood, Cabot, Monterey, and Cowpens), embarking more than 500 planes. Supporting the carriers was a large fleet of seven battleships, and numerous cruisers, destroyers, submarines, and other support ships. (Morison, 1961)

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.

Attack

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. (Morison, 1961). 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. 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.^[2] 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 with a bomb hit. (Morison, 1961)

Aftermath

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 take out 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 and 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

Jan 10th, 1944 Truk -> Kure
BB Yamato
DD Michishio
DD Asagumo
DD Fujinami

Jan 18th, 1944 Truk -> Yokosuka
CV Unyo
CVL Zuiho
DD Hatsushimo
DD Wakaba

Jan 19th, 1944 Truk -> Saipan
DD Umikaze

Jan 19th, 1944 Truk -> Rabaul
Kokuyo Maru
DD Maikaze

Jan 24th Truk -> Eniwetok
DD Suzukaze

Jan 25th, 1944 Truk -> Saipan
DD Akebon
DD Ushio
CV Unyo
supply ship Irako

Feb 1st, 1944 Truk -> Palau
BB Nagato
BB Fuso
CA Kumano
CA Suzuya
CA Tone
DD Akizuki
DD Isokaze
DD Tanikaze
DD Hamakaze
DD Urakaze

Feb 3rd, 1944 Rabaul -> Truk => Beppu
Hikawa Maru

Feb 3rd, 1944 Yokosuka -> Truk
CVL Zuiho

Feb 5th, 1944 Truk -> Davao
DD Ikazuchi

Feb 10th, 1944 Truk -> Palau
CA Atago
CA Chokai
CA Haguro
CA Myoko
DD Isokaze
DD Urakaze
DD Mamakaze
DD Tanikaze

Feb 10th, 1944 Truk -> Yokosuka
BB Musashi
CL Oyodo
CVL Chiyoda
CVL Zuiho
DD Wakaba
DD Hatsuharu
DD Shratsuyu
DD Michishio
DD Tamanami

Feb 12th, 1944 Truk -> Palau
DD Hamanami

Feb 13th, 1944 Truk -> Yokosuka
oiler Irako
oiler Notoro
Tatsuura
Hibi Maru
kaibokan Manji
kaibokan Oki
subchaser CH-31

Feb 13th, 1944 Truk -> Kure
CVE Kaiyo
DD Hibiki
DD Inazuma

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 15th, 1944
Asaka Maru
DD Yamagumo
DD Nowaki

Feb 17th, 1944 -> Truk
Ryuku Maru
DD Fujinami
minelayer Natsushima

Feb 17th, 1944 Truk -> Palau
DD Shigure
DD Harusame

Feb 17th, 1944 Truk -> Yokosuka
Akagi Maru, sunk
CL Katori, sunk
DD Maikaze, sunk
DD Nowaki, the only ship escaped
Shonan Maru #15, sunk

Feb 17th, 1944 Truk -> Yokosuka
DD Nowaki
DD Yamagumo
Asaka Maru

Feb 17th, 1944 Truk -> assist damaged Agano
CL Naka, sunk

Feb 18th, 1944 Truk -> Saipan
Tenno Maru

Feb 18th, 1944 Truk -> Palau
Akitsushima

Feb 20th, 1944 Truk -> Palau
Akashi
DD Fujinami
DD Akikaze

Feb 29th, 1944 -> Truk
Aratama Maru

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 DD Mutsukaze and Hakachi
DD Harusame (春雨) 白露型 1,685 tons, minor damaged 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 in U.S. air raid on Truk, while entering Truk via North Pass with survivors from CL Agano on Feb 18th
DD/P34 Sutsuki (薄) 樅型 935 tons, escaped but later sunk in a 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 cruisers Akagi Maru (赤城丸) 7,367 tons, sunk north of Truk
auxiliary cruisers Aikoku Maru （爱国丸) 10,348 tons, sunk off 4th fleet anchorage
auxiliary cruisers Kiyosumi Maru (清澄丸) 6,983 tons, sunk off repair anchorage
auxiliary submarine tenders Heian Maru (平安丸) 11,616 tons, sunk off repair anchorage
auxiliary submarine tenders Rio de Janeiro Maru (りおで志ゃねいろ丸) 9,627 tons, sunk off 6th fleet 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 chasers CH-24, 438 tons, sunk west of Truk
submarine chasers CHa-20, damaged
submarine chaser CH-29, 420 tons, sunk
auxiliary submarine chasers 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
ammunition ship/ice-breaking freighter Soya (宗谷) 3,800 tons, damaged
target ship Hakachi (波勝) 1,641 tons, damaged

List of ships at the time of attack and other shipwrecks in Truk's Anchorage

navy transport Yamagiri Maru (山霧丸) 6,439 tons , carrying Yamato's 46cm projectiles, sunk off combined fleet anchorage
navy transport/passenger/cargo ship Kansho Maru (乾祥丸) 4,861 tons, sunk off repair anchorage
navy trasnport/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 Taihou Maru (大邦丸) 2,829 tons,sunk off 6th fleet anchorage
navy transport Dai Roku Unkai Maru (第６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 Seigo Maru (西江丸)? 5,385 tons,sunk on Feb 17th, 1944
hospital ship Tenno Maru (天應丸) 6,067 tons, anchored next to Heian Maru, escaped

Zukai Maru
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 Dai Ni Hino Maru (第２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 Yuubae 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 Ojima 812 tons, accidentally sunk in an explosion with Kikukawa Maru on Oct 7th,1943
fleet tug Futagami 625 tons, sunk off repair anchorage

References

^ Morison, Aleutians, Gilberts and Marshalls, p. 330. Deaths included 29 aircrew plus 11 crewmen on Intrepid. Aircraft losses included 12 fighters, 7 torpedo-bombers, and 6 dive-bombers.
^ Morison, Aleutians, Gilberts and Marshalls, p. 330. Number derived by summing the total crews of the 25 aircraft lost and subtracting the number (29) listed as killed.

External links

Crowl, Philip A. (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. Retrieved 2007-01-23. {{cite web}}: Cite has empty unknown parameter: |month= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
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. {{cite web}}: Cite has empty unknown parameters: |coauthors= and |month= (help)
Jeffery, William (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. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help); Unknown parameter |month= ignored (help)
US Army Campaigns in World War II: Eastern Mandates
WW2DB: Attack on Truk
Account of the operation from Enterprise website
Account of aircrew rescue operations at Truk by U.S. submarine Tang
Moderately brief account of the attack
Diving site showing where many of the sunken Japanese ships are with background information
Franko's Guide Map of Chuuk Lagoon
TRUK LAGOON AREA STUDY

[1] Morison, Aleutians, Gilberts and Marshalls, p. 330. Deaths included 29 aircrew plus 11 crewmen on Intrepid. Aircraft losses included 12 fighters, 7 torpedo-bombers, and 6 dive-bombers.

[2] Morison, Aleutians, Gilberts and Marshalls, p. 330. Number derived by summing the total crews of the 25 aircraft lost and subtracting the number (29) listed as killed.

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