Attack on Pearl Harbor by Alan D. Zimm Page B

lengths. Cruising at 115 knots at 12,000 feet, an A6M Zero with an average pilot at the controls could consume as little as 18 gallons per hour out of a normal fuel load of 182 gallons, giving ten hours in the air. 37 First-wave fighters launched at 0600 could have remained over Oahu for hours after the second wave had departed, if asked to do so. First-wave fighters could have been posted over each of the airfields and remained for the duration of the attack, ensuring that nothing got off the ground until after the second wave had come and gone. On US carriers this was known as “double cycling,” and was usually done only with scout bombers on inner and outer AS patrols. US Fighters could be double-cycled after drop tanks were developed.
    Evidently no thought was given to taking advantage of the A6M Zero’s endurance. Instead, the fighters went in to the attack, expended their ammunition immediately, and joined up at the strike rendezvous point so the bombers could navigate them back to the carriers. The plan allowed the Americans a hiatus in the attack, time to recuperate from the effects of the first wave, recover and rearm what fighters they had gotten aloft, and prepare for the next wave.
    Bomber Allocation for the Main Effort
    The Intelligence Foundation
    The Japanese were blessed with extraordinarily good intelligence for their attack. The Japanese Navy assigned a reserve naval officer, Yoshikawa Takeo, a graduate of the Japanese naval academy who had been medically disqualified from active duty, as a member of the Japanese legation on Oahu. While posing as a diplomat, his true role was kept secret from the legation staff. His neglecting of his “duties” at the legation scandalized the regular diplomatic staff, as he traveled about Oahu under the guise of a gadabout.
    Almost daily he traveled to a tourist overlook surveying the beauties of Pearl Harbor and counted the fleet, noting mooring locations. He recorded the fleet’s operating patterns. He determined the day of the week when most ships would be in port. He took tourist flights over the harbor, one on the 5th of December accompanied by two young ladies of questionable repute, a rather ingenious and amiable way to conceal intelligence activities. He attended open house events staged at the various bases, where he was allowed to wander about unsupervised. He worked in the kitchen at the Pearl Harbor Officer’s Club, with access to the base and the officers’ gossip. Attending a “Galaday” at Wheeler Field in August when the airdrome was dedicated, he inspected the facilities thoroughly.
    Planners from the Naval General Staff also traveled to Hawaii aboard the civilian liner Taiyo Maru . This ship traveled along Kido Butai’s intended route to take weather observations, gauge the density of traffic (no ships sighted), and observe American reconnaissance (ineffective). At Honolulu they delivered an extensive list of questions to Yoshikawa regarding Pearl Harbor and its defenses.
    Yoshikawa divided Pearl Harbor into numbered squares and transmitted the locations of ships. Periodic messages to the Naval General Staff in Tokyo, sent through diplomatic channels, included the specific anchorages and moorings occupied by the ships, along with listings of daily arrivals and departures. Kido Butai received one of these messages the day before that attack, with the information a day late due to being retransmitted from Tokyo. As Kido Butai approached Hawaii, Yoshikawa provided last minute tactical intelligence on anti-submarine nets at the entrance to the harbor (yes), anti-torpedo nets around the battleships (no), and barrage balloons (no).
    The aviators had nearly exact information on the locations of moorings and berths and, more importantly, which normally hosted battleships and carriers. Each pilot was provided a map with the locations of their targets and the location of ground AA positions. They also were given aerial “Souvenir of Honolulu”