Air attacks describing the attack The three carrier task groups committed to
Hailstone moved into position and began launching their first fighter sweep 90 minutes before daybreak on 17 February 1944. No Japanese air patrol was active at the time, as the IJN's 22nd and 26th Air Flotillas were enjoying shore leave after weeks on high alert following the Liberator sightings. Similarly problematic for the Japanese, radar on Truk was not capable of detecting low-flying planes—a weakness probably known and exploited by Allied intelligence organizations. Furthermore, radar stations were not adequately manned and telephone communications were poor. Because of these factors, U.S. carrier aircraft achieved total surprise. Japanese pilots scrambled just minutes before TF 58 planes arrived over Eten, Param, Moen, and Dublon Islands. Though more than 300
Imperial Japanese Navy Air Service (IJNAS) and
Imperial Japanese Army Air Service (IJAAS) planes were present at Truk on the first day of the attacks, only about half of them were operational, compared to over 500 operational aircraft among the carriers of TF 58. U.S. Navy fighter pilots in their
Grumman F6F Hellcats, with the advantages of speed, altitude, armor, and surprise, achieved a one-sided victory against IJNAS pilots flying
Mitsubishi A6M Zero fighters. As many as 30 of the 80 Zeros sent up in response to the fighter sweep were shot down during the battle. Only token aerial resistance was encountered for the rest of the morning; almost no Japanese aircraft were present by the afternoon. Due to the lack of air cover or warning, many merchant ships were caught at anchor, with only the islands' anti-aircraft guns for defense against American carrier planes. Some vessels outside the lagoon already steaming towards Japan were attacked by American submarines and sunk before they could make their escape. Other Japanese ships attempting to flee via the atoll's North Pass were bottled up by aerial attack and by Admiral Spruance's surface force, Task Group 50.9, which circumnavigated Truk, bombarding shore positions and engaging enemy ships.
Torpedo bomber and
dive bomber squadrons from the American carrier air groups (CAGs) were responsible for the bulk of the damage inflicted on Japanese ground facilities. Early on the first day of
Hailstone,
Grumman TBF Avenger torpedo bomber squadrons from
Enterprises Carrier Air Group 10 (CAG-10) and
Intrepids CAG-6 dropped fragmentation and incendiary bombs on runways at
Eten Island and the seaplane base on
Moen Island. Dozens of aircraft were damaged or destroyed on the ground, further blunting any possible response by the Japanese to the strikes. Subsequent joint attacks by dive bombers and Avenger torpedo bombers cratered runways and destroyed hangar facilities. Morning strikes were also launched against shipping in the lagoon. Lieutenant Commander
James D. Ramage, commanding officer of Dive Bombing Squadron 10 (VB-10), is credited with sinking the previously damaged
merchant tanker Hoyo Maru. Lieutenant James E. Bridges and his crew in one of
Intrepids Torpedo Squadron 6 (VT-6) Avengers scored a direct hit on the ammunition ship . The torpedo detonation set off the ammunition carried near the bow, resulting in a tremendous explosion which immediately sank the ship taking down 945 crew and passengers, and also engulfed Bridge's plane. By the second and third strikes of the day, CAG action reports listed the apparent enemy mission as "escape". Japanese ships that were able to make for open sea steamed for the North Pass exit from the lagoon while weathering repeated aerial attacks. One particular group of warships – the cruiser
Katori, auxiliary cruiser
Akagi Maru, destroyers
Maikaze and
Nowaki, and minesweeper
Shonan Maru – was given special attention by carrier bombers. Multiple air groups attacked these ships, inflicting serious damage.
Yorktowns dive- and torpedo-bombing squadrons claimed two hits on the violently maneuvering
Katori and hits on another cruiser and multiple destroyers;
Essex bombers claimed five hits on a , stating that the ship was stopped dead in the water after the attack.
Akagi Maru was sunk by air attacks.
Surface action At this point, reports reached Admiral Spruance concerning the group of warships fleeing through North Pass. Spruance was so adamant on engaging in ship-to-ship combat that his carrier commander, Admiral Mitscher, ordered his CAGs to stop attacking
Katori and her companions. Spruance put himself in tactical command of Task Group 50.9, made up of four destroyers, heavy cruisers
Minneapolis and
New Orleans, and the new battleships and , which he personally led in a surface engagement against the previously damaged Japanese ships. The battered Japanese ships did not stand much of a chance against Task Group 50.9, though members of his staff saw Spruance's decision to engage in surface action when aircraft likely could have achieved similar results as needlessly reckless. Indeed, the Japanese destroyer
Maikaze managed to fire torpedoes at the battleship
New Jersey during the engagement. Fortunately for Spruance, the torpedoes missed, and the "battle" ended with predictably one-sided results. The U.S. Navy surface combatants received virtually no damage, and it was the only time that
Iowa and
New Jersey fired their main guns at enemy ships. Meanwhile, ''New Jersey's
5-inch (127 mm) guns combined fire with U.S. cruisers to sink Maikaze
and Shonan Maru
, while Iowa
targeted and sank Katori
, which was already dead in the water, with numerous hits from her main battery. Nowaki
was the only Japanese ship from this group to escape, sailing through a gauntlet of fire from Iowa
and New Jersey
, only suffering very minor damage at the hand of a straddle from a high capacity, 16-inch (406 mm) round from New Jersey'' at the extremely long range of 35,700 yards (20.3 statute miles).
Japanese night raid Retaliation for the day's strikes arrived late at night in the form of small groups of Japanese bombers flying out of Truk and Formosa probing the task groups' defenses. From roughly 21:00 on 17 February to just minutes past midnight on 18 February, at least five groups of between one and three enemy planes attempted to sneak past screening ships to strike at the fleet carriers. One lone
Rikko-type twin engine bomber from the
755th Kōkūtai (Genzan Air Group) made its attack on Task Group 58.2 and torpedoed the starboard quarter of the
Intrepid, damaging steering control and killing 11 sailors.
Intrepid was forced to retire to the U.S. for repairs and did not return to combat until August 1944. ==Assessment of the attack==