Operation K - Execution

Execution

When time came for the raid, only two of the big flying boats were available. Pilot Lieutenant Hisao Hashizume was in command of the mission, with Ensign Shosuke Sasao flying the second airplane. They were sent to Wotje Atoll in the Marshall Islands, where each airplane was loaded with four 550-pound (250 kg) bombs. From there, they flew 1,900 miles (3,100 km) to French Frigate Shoals to refuel, then set off for O'ahu, 560 miles (900 km) distant. In addition to their reconnaissance mission, they were to bomb the "Ten-Ten" dock - named for its length, 1,010 feet (310 m) - at the Pearl Harbor naval base to disrupt salvage and repair efforts. However, a comedy of errors ensued on both sides.

The Japanese submarine I-23 was supposed to station itself just south of Oahu as a "lifeguard" and weather spotter for the flying boats, but was lost sometime after February 14.

American radar stations on Kaua'i (and later O'ahu) picked up and tracked the two planes as they approached the main Hawaiian Islands, prompting a search by P-40 Warhawk fighters. PBY Catalina flying boats were also sent to seek Japanese aircraft carriers, which were assumed to have launched the two invaders. However, heavy clouds (and possibly an overcast below the H8Ks) prevented the defenders from spotting the Japanese planes, which were flying at an altitude of 15,000 feet (4,600 m).

Those same clouds also confused the IJN pilots. Using the Ka'ena Point lighthouse for a position fix, Hashizume decided to attack from the north. Sasao, however, did not hear Hashizume's order and instead turned to skirt the southern coast of Oahu.

Hashizume, having lost sight of his wingman, and only able to see small patches of the island, dropped his four bombs on the slopes of Tantalus Peak, an extinct volcano cinder cone just north of Honolulu sometime between 2-2:15am HST. He was unable to see Pearl Harbor, the only lit facility on Oahu due to blackout conditions intended to hinder air raids. Hashizume's bombs landed about 1,000 feet (300 m) from Roosevelt High School, creating craters 6–10 feet (1.8-3 m) deep and 20–30 feet (6.1-9.1 m) across. Damage was limited to shattered windows. Sasao is assumed by historians and officials to have eventually dropped his bombs into the ocean, either off the coast of Wai'anae or near the sea approach to Pearl Harbor. The two flying boats then flew southeast toward the Marshall Islands. Sasao returned as planned to Wotje atoll, but Hashizume's airplane had sustained hull damage while taking off from French Frigate Schoals. Fearing the primitive base at Wotje was insufficient to repair the damage, Hashizume proceeded non-stop all the way to their home base at Jaluit Atoll, also in the Marshall Islands. That made his flight the longest bombing mission in history up to that point.