How the Navy's most important ships avoided destruction at Pearl Harbor

• The attack on Pearl Harbor was a massive blow to the US Navy, costing it thousands of sailors, hundreds of airplanes, and many ships. But not all was lost.
• By chance, all three of the Pacific Fleet's carriers were at sea on missions and survived the attack, and they would go on to determine the outcome of the war.

At 7:48 a.m. on December 7, 1941, 183 Japanese fighters, dive bombers, and torpedo bombers descended on the US Navy's Pacific Fleet base at Pearl Harbor in Hawaii. They swarmed airfields and warships with bombs and torpedoes, causing a massive amount of damage.

A little more than an hour later, a second wave of 167 aircraft arrived, wreaking more havoc before returning to six Japanese aircraft carriers some 240 miles off the coast of Hawaii.

By the time the smoke cleared, the crippling damage was apparent. At the cost of 29 planes and five mini submarines, the Japanese had sunk or heavily damaged all the Pacific Fleet's eight battleships. Three cruisers, three destroyers, and a number of other ships were seriously damaged.

There were 188 US aircraft destroyed and 157 damaged. The attack killed 2,335 US servicemen and wounded 1,143 more, in addition to 68 civilians killed and 34 wounded. The Japanese lost 129 servicemen and had one submarine crewman captured.

It was a massive blow to the US Navy. But not all was lost. By chance, all three of the Pacific Fleet's carriers were on missions and survived the attack.

Preparing for war

Though the attack on Pearl Harbor was a complete surprise, the US had long believed that war with Japan was a realistic possibility. Japan's actions in China and Southeast Asia had provoked a furious diplomatic response, with the US placing embargoes on Japan and freezing its assets.

The US also prepared its military. The Pacific Fleet moved from its original base in San Diego to Pearl Harbor in April 1940, and the US was reinforcing and strengthening the defenses of its Pacific territories.

Official messages sent to Pearl Harbor's commanders on November 27 stated "this dispatch is to be considered a war warning," and warned that "an aggressive move by Japan is expected within the next few days."

The Navy had seven carriers in service at the time.

Four - Ranger, Yorktown, Hornet, and Wasp - were stationed on the East Coast, poised to deal with Germany's U-boats, which had caused a number of incidents already. The three carriers of the Pacific Fleet - Enterprise, Lexington, and Saratoga - were being used to support reinforcement efforts in the Pacific.

USS Enterprise

Enterprise was the closest American carrier to Pearl Harbor on December 7 and actually did contribute to its defense.

It left Pearl Harbor on November 28 with an escort of three heavy cruisers and nine destroyers on a mission to transport 12 Marine Corps F4F-3 Wildcat fighters to Wake Island. It completed the mission on December 4 and was heading back to Pearl with an expected return date of December 6 but was delayed by poor weather.

On the morning of the attack, Enterprise was some 215 miles west of Oahu. It sent 18 SBD Dauntless dive bombers out on patrol as it sailed to Pearl. The dive bombers were to land in Hawaii ahead of the carrier's arrival, but by complete coincidence, they ran into the middle of the first wave of Japan's attack.

The dive bombers immediately joined the battle. Seven were shot down by the Japanese or by friendly fire, with eight pilots and crew killed and two wounded. At least one Zero was shot down by one of Enterprise's aircraft.

After the attack, Enterprise was ordered to send an attack force to find and destroy the Japanese carriers, which the Navy incorrectly believed was south of Oahu.

Unable to find the carriers, the dive bombers returned to Enterprise, while the fighters flew to Pearl Harbor, where some were shot down by friendly fire.

USS Lexington and USS Saratoga

Like Enterprise, Lexington was taking aircraft to an American base in the Pacific. The carrier and its escort of three heavy cruisers and five destroyers had left for Midway on December 5 to deliver 18 Marine Corps SB2U Vindicator dive bombers.

On the morning of the attack, Lexington was about 500 miles southeast of Midway but was ordered to return once the attack started.

Lexington was then ordered to search for the Japanese fleet southwest of Hawaii. Unable to find the Japanese and running low on fuel, Lexington returned to Pearl Harbor, arriving on December 13.

Saratoga was in San Diego on the day of the attack, having just arrived from Puget Sound Navy Yard, where it underwent an eight-month refit.

Saratoga was in San Diego to receive its air wing, which had been training in Southern California during the refit. The carrier was also expected to pick up a Marine Corps air squadron and other aircraft to be delivered to Pearl Harbor.

The day after the attack, Saratoga was made the flagship of Carrier Division One and set sail for Pearl Harbor, arriving on December 15.

A missed opportunity

The Japanese were aware that the American carriers were not at Pearl Harbor.

After some debate, they decided the chance to destroy all eight US Pacific Fleet battleships - still seen as the dominant naval weapon at the time - was just too good an opportunity to pass up.

But the war in the Pacific would show that the carrier was king of the seas. American carriers played decisive roles in the battles of the Coral Sea and Midway, and would prove to be the deciding factor in the most important naval battles of the war.

Carriers became so important that the US poured a massive amount of resources into building them. By the end of the war, the US had 28 fleet carriers and 71 smaller escort carriers.