OPERATION HAILSTONE
Now the Marshall islands were captured, Nimitz was proven right. Wanting to maintain momentum it was decided to invade the Eniwetok Atoll, which was needed as staging base for the invasions of the Carolina and Mariana Islands.
There was only one issue - Truk.
Truk consisted of an enormous coral reef surrounding 6 principle islands. The ring around the atoll had 4 openings covered by coastal defence guns. As it was consistently hidden from world view by the Japanese it had somehow obtained a reputation of nearly unsurmountable strength. One air group commander would say, that his first impulse on learning target was to jump overboard (source: u.s. naval institute/two-birds-one-hailstone)
It soon was proven that this reputation was greatly overblown, only 10,000 to 12,000 Japanese soldiers and sailors were on the Atoll, and Truk had only 40 anti aircraft guns, of which, way worse, all lacked radar. At the time of the raid 160 planes were ready for battle, with an other 180 ready for delivery to Rabaul.
Operation Hailstone would be conducted by Admiral Spruance, commander of the US 5th fleet, fast carriers. Weeks before the operation rear admiral Charles A. Pownall was replaced by Rear Admiral Marc A. Mitscher. Pownall was considered not aggressive enough by Nimitz' headquarters. Mitscher on the other hand grew up with naval aviation and had served on the Navy's first carrier the Langley (CV-1) - he enjoyed respect from the carrier commanders. His style of command was particularly appreciated ; "I tell them what I want done - not how!"
To gather information about Truk, two marin PB41Y-1 Liberators flew from Bougainville to collect intelligence. Even though the view was partially obscured by clouds, main ships both naval and merchant were observed. Admiral Koga, the successor to admiral Yamamoto, already considered the vulnerability of Truk and began to move out the combined fleet. After spotting the liberators, this plan was accelerated and the main fleet departed to Japan.
Spruance
Spruance 5th fleet included 12 carriers, which were organized in four carrier groups. As he wasn't expecting not too much naval opposition at Eniwitok, he only sent one carrier group there. The other three groups, organised as Task Force (TF) 58 where heading for Truk. For more on task force 58 see the seperate page The task force consisted of five heavy carriers and four light carriers. Spruance transferred his flag to the battleship New Jersey (BB-62) as he was hoping to engage vessels fleeing the lagoon. This was also the first operation for the New Jersey as a flag ship. On 17 and 18 February the task force sank two Japanese Light cruisers, four destroyers, three auxiliary cruisers, two submarine tenders and and armed trawler and 23 other vessels. The New Jersey sank the destroyer IJN Maikaze.
IJN Cruiser Katori had departed Truk shortly before the attack, escorting the armed merchant cruiser Akagi Maru, destroyers Maikaze and Nowaki, and minesweeping trawler Shonan Maru No. 15 towards Yokosuka, but came under attack by Grumman F6F Hellcat fighters and Grumman TBF Avenger torpedo-bombers from the carriers Yorktown, Intrepid, Essex, Bunker Hill and Cowpens. Akagi Maru was sunk, and Katori was hit by a torpedo which did minor damage.
Although aircraft could have finished off Katori, Admiral Spruance wanted a surface engagement, so Admiral Mitscher waved off further air attacks on the damaged light cruiser. Because of this, several hours later, Task Group 50.9's battleships New Jersey and Iowa, along with cruisers Minneapolis and New Orleans and destroyers Bradford and Burns, spotted the Katori group and opened fire. The screening destroyers fired six salvos of torpedoes at Katori (which was already listing slightly to port and on fire amidships), but all torpedoes missed. Katori responded with a salvo of torpedoes which were equally ineffective.
Mitscher
Mitscher led Task Force 58 in a raid against Truk, Satawan and Ponape (February 17–18).[33] This was a big step up. The idea of purposely sailing into the range of a major Japanese naval and air base brought great unease to Mitscher's airmen. Said one: "They announced our destination over the loudspeaker once we were underway. It was Truk. I nearly jumped overboard. But Mitscher felt confident they could succeed. As tactical commander of the striking force, he developed techniques that would help give his airmen the edge of surprise. In Operation Hailstone, Mitscher's forces approached Truk from behind a weather front to launch a daybreak raid that caught many of the defenders off guard. The airmen brought devastation to the heavily defended base, destroying 72 aircraft on the ground and another 56 in the air, while a great number of auxiliary vessels and three warships were sunk in the lagoon. Chuckling over the pre-raid fears, Mitscher commented, "All I knew about Truk was what I'd read in the National Geographic."
The Japanase Admirals
The Japanses had been using a different tactic throughout the war which worked well for them in the past, which was influenced by their Victory over the Czarist Russian Fleet in 1905. The "one decisive battle" and "winner takes it all" was further refined, and was clearly seen back in the massive attack on Pearl Harbour, the battle of Midway or the Leyte gulf. Unfortunately for the Japanese themselves, Yamamoto was proven right, if America could not be brought down to it's knees quickly or to the negotiation table, the odd would turn quickly against Japan. Where in the beginning the Japanese fleet was on par with the Americans, the mighty American war complex was at full steam and soon the Japanese were falling behind, specially when it came to carriers. It was not only the loss of tonnage which played into the demise of the Japanese fleet, also the loss of planes, and worse, experienced pilots, rendered the available carriers useless. Any new supplies for the Japanese were effectively neutralised by succesfull USN Submarines. Admiral Koga (Who replaced Yamamato) could not stage a massive strike anymore and was forced time after time to take steps back. He now also had to avoid the added danger of surprise air attacks as the US creeped in on the home land. It was made more difficult in two ways now for the Japanese. They were pushed into the offensive, something they never even planned or thought about, and the war shifted from capital battleships to the carrier ships with their planes which could deliver painful blows deep into Japans territory. It would quickly become painfully clear that the capital battleships Yamoto and Musashi were almost useless and moreover even defenceless without supporting air cover. The Imperial Navy had to accept that it had way too much tonnage which was effective during the beginning of the war, but was now not very usefull anymore.
The Japanese command took the right decision to evacuate the majority of the fleet from Truk. If you look at the map of the Pacific Theatre you can clearly see that Truk was massivly exposed to both the task force of MacArthur/Halsey/Nimitz from the south and Spruance from the North East.
Admiral Koga even ordered preparation for the preparations of the defences of the Mariana, specially Saipan, Guam and Palau, but his orders were ignored, "not received" or simply not believed. Just when his worst fears were coming true, he died in plane crash during a violent storm.
Operation Hailstone
17-18 February 1944
Preparations to operation Hailstone
As already pointed out in various literature, the Japanese never really counted on a multiple front battle in the Pacific. They didn't foresee the advances from New Guinea to Solomons and Marshalls (see the map above). This meant that their resources were going to be stretched out thin and left Truk more and more exposed. It also mean their resources had to move around a lot, using scarce fuel and to make matters worse, even be at the wrong place at the wrong time. To make matters worse, USN Submarine were always lurking around creating havoc among the moving assets.
During the prewar period the US concept was widely that the carrier groups were "hit and run" units (source : history.navy.mil) and this was still very much enbedded in the navy during 1943-1944. Staying in one place, and sitting it out with a big land based airforce was still considered by a lot a really bad idea. However, around early 1944 the commander of the US Pacific Fleet Admiral Nimitz (see above) decided that it was time to put a dent in Truk's reputation. He realised he had enough resources to conduct a multi day attack on the Japanese held Atoll, and with his agressive rear Admiral Mitcher he had the right man for the job.
On the other side of the ocean, admiral Koga had exactly the same idea... and decided it was time to move the combined fleet out of Truk.
Truk represented a significant danger to other US operations, the Japanese Combined fleet had been deployed to Eniwetok during the battle of Wake Island in October 1943 and burned up a lot of scarce fuel. Normally most of the Combined fleet, due to fuel shortage and the US Submarines would stay safely in Truk Lagoon, the lagoon was big enough to protect the ships from gunfire outside the lagoon. The islands were protected by about 7,500 entrenched Japanese soldiers and an other 3 to 4,000 soldiers ashore occupied with the support functions at the airstrips, ports etc. etc. The islands were protected by 40 major caliber anti aircraft guns, with only one problem. The control radar for these anti aircraft guns had gone down on a transport ship sunk by a US submarine.
The greatest concern of any attacking force where the 300 to 400 airplanes stored at the islands.
The commander of the US 5th fleet, now vice Admiral Spruance took personal command of task force 50- taking his flag from the heavy cruiser Indianapolis to the new battleship New Jersey. The fast carrier force 58 was under command of Rear Admiral Mitscher who embarked on the Yorktown. The force now was made up by the four new Essex class carriers, the Yorktown, Essex, Intrepid and the Bunker Hill. plus the Enterprise and four light carriers with 500 aircraft. Added to that six new fast battleships, ten cruisers and 28 destroyers completed the full force. For more on the task force please see the separate page on task force 58
Rewrite / with book truk lagoon data:
On 12/13 February 1944, three fast carrier task groups departed Majuro Atoll (recently captured in the Marshall Islands) and topped off from five tankers before making a high-speed run toward Truk. These task groups included
TG58.1, Commander Carrier Group 1,
Rear Admiral John W. Reeves
Enterprise, Yorktown, Belleau Wood, three light cruisers, and one anti-aircraft cruiser
TG 58.2, Commander Carrier Group 2,
Rear Admiral Alfred .E. Montgomery
Essex, Intrepid, Cabot, three heavy cruisers, and one anti-aircraft cruiser;
TG 58.3, Commander Carrier Group 3,
Rear Admiral Frederick C. Sherman,
Bunker Hill, Monterey (future U.S. President Lieutenant Gerald Ford in crew)
Cowpens, and battleships North Carolina (BB-55), Iowa (BB-61), New Jersey (BB-62, Vice Admiral Spruance embarked), Massachusetts (BB-59), South Dakota (BB-57), Alabama (BB-60), and two heavy cruisers.
TF 58 reached the launch point 90 nautical miles northeast of Truk on 17 February and commenced launching an hour and a half before dawn.
17 FEBRUARY 1944
The first succes of the day (actually the day before on the 16th) came quick in the form of the American Submarine Skate (SS-305) spotted and sank the Japanese light cruiser Agano. The Skate fired four torpedoes, of which two hit the cruiser on starboard side at 16:44 flooding the boiler room no.2 causing a large list and subsequent fire. The escorting destroyer Oite rescued 523 survivors from water during the evening.
The Oite now turned back to Truk to bring the surviving crew back. When it arrived in the morning at Truk it was attacked by US Navy planes when it was entering the harbour on the 18th of February. She was torpedoed, broke in half and immediately sank taking with her 172 of the 192 crewmen, and also the 523 survivors of the Agano.
The task force reached it's scheduled launch point half an hour before daybreak, (90 nautical miles northeast of Truk) and commenced launching. The first wave consisted out of out of a 72 plane group formed from from the 5 US carriers.
The Japanese were caught by total surprise, after they had been on high alert for twee weeks after a US reconnoissance flight was spotted weeks earlier. As nothing happened, the high alert was was lifted just before the raid.
Rear admiral Mitscher devised the fighter sweep technique. 45 Japanese fighters scrambled into the air only minutes before the US planes arrived, and an other 45 were able to get airborne during the raid. 30 Japanese fighters were shot down and 40 more were destroyed by strafing, at only the cost of the loss of 3 US planes. The fighter sweep was immediately followed by 18 avengers (see picture below) dropping incendiary and cluster fragmentation bombs. In the afternoon there was no more resistance in the air from the Japanese.
Of the 365 Japanese airplanes at Truk before the raid, only 100 survived.
As operations started at 0443 the 5 light carriers began a staggered launch, resulting in a continuous flow of aircraft getting to Truk during the whole morning. During the whole day there were about 30 US airstrikes delivering 369 1,000-pound bombs, 498 500-pound bombs and 70 torpedoes.
One of the commanders of the bombing raid, (future rear admiral James D. Ramage) sank the merchant tanker Hoyo Maru.
An avenger flown by Lt. James E. Bridges which launched from the Intrepid, hit the ammunition ship Aikoku Maru. As the ship was an ammunition vessel, she immediately blew up and as the explosion was so violent (see image below) the plane and it's crew were also obliterated. (We dived the wreck but didn't take any images - on the list for 2025).
The destroyer Fumizuki (see the relevant page) had a near miss, but her crew could not control the flooding and she sank the next day.
An other destroyer, the Tachikaze, had already run aground on the 4th of February and was hit by a torpedo and sank. The Oite's faith is already described above.
Some of the vessels in Truk lagoon tried to escape, but were eagerly awaited by submarines whilst others were blocked by US air attacks or just simply attacked by US surface vessels. The light cruiser Naka was caught when she tried to flee 35nm west of Truk by several waves of Helldivers and Avengers from the Bunker Hill and Cowpens.
Whilst US nacy aircraft were slaughtering ships inside the lagoon, Vice Admiral Spruance led a cruise around the atoll on the 17th of February to catch any vessels trying to escape, and to bombard shore installation as they went.
The new battleships New jersey and Iowa, heavh cruisers Minneapolis and New Orleans and four destroyers caught the light cruiser Katori. The Katori, the aux. cruiser Akagi Maru the destoyers Maikaze and Nowaki had left Truk before the beginning of the attack but had not gotten away far enough. Aircraft from several carriers had already crippled the group of small ships. The Akagi Maru was hit by a number of bombs which caused several large explosions and her crew abandoned her. The katori, despite being heavily damaged, took on all the survivors of the Akagi, although all would be lost when the Katori itself would go down. This tragedy costed the life of 788 crewmean and 512 passengers.
The Katori was already crippled when she took on board the survivors of the Akagi Maru, and aircraft could have finished her off. Vice admiral Spruance wanted a surface engagement. So Mitscher stopped any further air attacks on the already crippled cruiser. Some aviators and even some of Spruance's own staff found this pretty reckless. Spruance directed the Minneapolis, New Orleans and tow destroyers to engage the Katori. The destroyers Bradford (DD-545) and Burns (DD-588) fired several rounds of torpedoes at the Katori, all of which missed. The katori fired a round of torpedoes herself which also all missed. She was put out of her misery by the Iowa which fired 46 16-inch shells and 124 5-inch shells at her, hitting her multiple times. She continued to fight untill the bitter end, her guns still firing as she rolled over sank. (see picture below). Even though there were survivors in the water, none were rescued by the US nor the Japanese.
As the Katori took her beating, the destroyer Maikaze stood by her side. The Maikaze managed to fire a salvo of torpedoes towards to the battleship new Jersey (BB-62). By luck the torpedoes were spotted by a plane which warned the New Jersey which could take evasive manouvres. The torpedoes passed the bow without doing any damage. Vice admiral Spruance said : "That might have been embarrassing (if the the torpedoes would have hit) " The Maikaze took a massive beating too and sank whilst still firing. The small trawler in the group, the Shonan Maru no 15 but up a hell of a fight against the destroyer Burns, but eventually lost and sank with all hands.
The other destroyer manage to get out and put some distance between her and the attack group. However, the New Jersey and Iowa pursued and opened fire at a long distance. (22 miles) she was eventually believed to be sank by a torpedo fired by destroyer Owen, The destroyer Burns in the mean time was attacked by a Japanese Subchaser the CH-24 which opened fire at her with her single 3-inch gun. Brave but no match to the 5 inch guns of the Burns. The Burns tried to rescue the 60 surviving crew, who refused to be rescued. They took out 6 survivors, and had to drop three depth charges on them to secure them not fighting an other day....
Most of the Japanese counter attacks were futile, US anti aircraft fire kept any attacking planes away from the fleet. However, at around 2211 a kate bomber plane dropped a torpedo which into the starboard quarter of the intrepid jamming her rudder and killing 11 sailors on board. Her damages where so extensive she had to return to Pearl Harbour for repairs.
Overnight the attacks continued and breaking with the tradition of hit and run operations. It was also the first time night time fighting was tried, and the USS Enterprise continued to execute night raids.
The Japanese had lost between 250 and 275 aircraft and 75 percent of their supplies on Truk. Japanese warship losses included two light cruisers, four destroyers, two submarine chasers, one auxiliary minesweeper, and a motor torpedo boat. Additional ships sunk included three auxiliary cruisers, 16 Navy transport ships, three Army transport ships, one freighter, two submarine tenders, and––probably most valuable––five tankers. Damaged ships included two destroyers, two submarines, a repair ship, a seaplane tender, a submarine chaser, and a target ship. One additional cargo ship was also damaged.
The cost to the United States of Operation Hailstone was one fleet carrier damaged, one battleship slightly damaged, 25 aircraft lost, and 40 dead. A number of U.S. aircrew were rescued by submarine. In one case, a Kingfisher float plane launched from the heavy cruiser Baltimore, flown by Lieutenant Junior Grade D. F. Baxter, flew right into the lagoon and rescued an Essex Hellcat pilot that had been shot down on the morning fighter sweep of 18 February, while nine other Hellcats held a Japanese destroyer at bay. The submarine Searaven (SS-196) also rescued the entire three-man crew of a Yorktown Avenger.
The Japanese never again used Truk as a major fleet anchorage, and the devastating carrier attack was a huge blow to Japanese morale (and a big boost to U.S. carrier pilots’ morale and confidence). At the time of the attack, Allied commanders had not yet decided whether Truk would need to be invaded or could be bypassed. On 12 Mar 1944, Admiral Nimitz made the decision to bypass it.
* source. : Naval History and Heritage Command
Admiral's chat
Admiral Spruance : "When I look at myself objectively," he wrote in retirement, "I think that what success I may have achieved through life is largely due to the fact that I am a good judge of men. I am lazy, and I never have done things myself that I could get someone to do for me." "Some people believe that when I am quiet that I am thinking some deep and important thoughts, when the fact is that I am thinking of nothing at all. My mind is blank."
Admiral Mitscher : Chuckling over the pre-raid fears, Mitscher commented, "All I knew about Truk was what I'd read in the National Geographic."
During the sinking of the Katori, a nearby destroyer called the Maikaze was able to fire a good salvo of torpedoes to the battleship New Jersey. Thanks to an overhead plane the New Jersey was warned and the torpedo passed just ahead. Vice Admiral Spruance remarked: "That would have been embarrassing - had the torpedoes hit"