|Attack on Pearl Harbor|
|Approach and attack|
|Possible third wave|
Several Japanese junior officers, including Mitsuo Fuchida and Minoru Genda, the chief architect of the attack, urged Nagumo to carry out a third strike in order to destroy as much of Pearl Harbor's fuel and torpedo storage, maintenance, and dry dock facilities as possible. Military historians have suggested the destruction of these would have hampered the U.S. Pacific Fleet far more seriously than loss of its battleships. If they had been wiped out, "serious [American] operations in the Pacific would have been postponed for more than a year." Nagumo, however, decided to withdraw for several reasons:
* American anti-aircraft performance had improved considerably during the second strike, and two thirds of Japan's losses were incurred during the second wave. Nagumo felt if he launched a third strike, he would be risking three quarters of the Combined Fleet's strength to wipe out the remaining targets (which included the facilities) while suffering higher aircraft losses.
* The location of the American carriers remained unknown. In addition, the Admiral was concerned his force was now within range of American land-based bombers. Nagumo was uncertain whether the U.S. had enough surviving planes remaining on Hawaii to launch an attack against his carriers.
* A third wave would have required substantial preparation and turnaround time, and would have meant returning planes would have had to land at night. At the time, no navy had developed night carrier techniques, so this was a substantial risk.
* The task force's fuel situation did not permit him to remain in waters north of Pearl Harbor much longer, since he was at the very limits of logistical support. To do so risked running unacceptably low on fuel, perhaps even having to abandon destroyers en route home.
* He believed the second strike had essentially satisfied the main objective of his mission — the neutralization of the Pacific Fleet — and did not wish to risk further losses. Moreover, it was Japanese Navy practice to prefer the conservation of strength over the total destruction of the enemy.
At a conference aboard Yamato the following morning, Yamamoto initially supported Nagumo. In retrospect, sparing the vital dockyards, maintenance shops, and oil depots meant the U.S. could respond relatively quickly to Japanese activities in the Pacific. Yamamoto later regretted Nagumo's decision to withdraw and categorically stated it had been a great mistake not to order a third strike.
Around Pearl Harbor, divers from the Navy (shore and tenders), the Naval Shipyard, and civilian contractors (Pacific Bridge and others) began work on the ships which could be refloated. They patched holes, cleared debris, and pumped water out of ships. Navy divers worked inside the damaged ships. Within six months, five battleships and two cruisers were patched or refloated so they could be sent to shipyards in Pearl and on the mainland for extensive repair.
Intensive salvage operations continued for another year, a total of some 20,000 hours under water. Oklahoma, while successfully raised, was never repaired. Arizona and the target ship Utah were too heavily damaged for salvage, though much of their armament and equipment was removed and put to use aboard other vessels. Today, the two hulks remain where they were sunk, with Arizona becoming a war memorial.
Despite the perception of this battle as a devastating blow to America, only three ships were permanently lost to the U.S. Navy. These were the battleships Arizona, Oklahoma, and the old battleship Utah (then used as a target ship); nevertheless, much usable material was salvaged from them, including the two aft main turrets from Arizona. The majority of each battleship's crews survived; there were exceptions as heavy casualties resulted from Arizona’s magazine exploding and the Oklahoma capsizing. Four ships sunk during the attack were later raised and returned to duty, including the battleships California, West Virginia and Nevada. California and West Virginia had an effective torpedo-defense system which held up remarkably well, despite the weight of fire they had to endure, resulting in most of their crews being saved.
Chester Nimitz said later, "It was God's mercy that our fleet was in Pearl Harbor on December 7, 1941.". Nimitz believed if Kimmel had discovered the Japanese approach, he would have sortied to meet them. With the American carriers absent and Kimmel's battleships at a severe disadvantage to the Japanese carriers, the likely result would have been the sinking of the American battleships at sea in deep water, where they would have been lost forever with tremendous casualties (as many as twenty thousand dead), instead of in Pearl Harbor, where the crews could easily be rescued, and six battleships ultimately raised. This was also the reaction of Joseph Rochefort, head of HYPO, when he remarked the attack was cheap at the price.
Many of the surviving battleships were heavily refitted, including the replacement of their outdated secondary battery of anti-surface 5-inch (127 mm) guns with more useful turreted dual-purpose (antiaircraft and antiship) guns, allowing them to better cope with the new tactical reality. Addition of modern radar to the salvaged vessels would give them a marked qualitative advantage over those of the IJN.
The attack on Pearl Harbor failed to sight, or destroy, any of the Pacific Fleet's aircraft carriers; they had been designated as primary targets along with the battleships. The carriers Lexington and Enterprise were ferrying additional fighters to American bases on the islands of Wake and Midway. At the time of the Japanese attack, the US was expecting imminent war with Japan, beginning in any of several places, such as the Philippines or Allied bases in Borneo. Nagumo's hesitation, and failure to find and destroy the American carriers, may have been a product of his lack of faith in the attack plan, and of the fact he was a gunnery officer, not an aviator. In addition, Yamamoto's targeting priorities, placing battleships first in importance, reflected an out-of-date Mahanian doctrine, and an inability to extrapolate from history, given the damage German submarines did to British trade in World War I. In the end, Japan achieved surprisingly little for all her daring and apparent success.
Cruisers, essential to carrier task forces later in the war, had been considered tertiary targets and only three suffered damage. Of 27 destroyers present, only two were lost: Cassin and Downes were total losses as ships, but their machinery was salvaged and fitted into new hulls, retaining their original names, while Shaw was raised and returned to service.