The Pacific War Online Encyclopedia

French Frigate Shoals

Photograph of La Perouse Pinnacle at French Frigate Shoals

French Frigate Shoals (166.280W 23.867N) is an almost uninhabitable atoll of the Hawaiian chain located 530 miles (850 km) west-northwest of Pearl Harbor, about halfway between Oahu and Midway. The atoll is some 18 miles (29 km) across and is almost completely submerged. There is a small, crescent-shaped island, Tern Island, on the northwest end of a shallow lagoon dotted with some 16 islets and open to the west. The most imposing feature is La Perouse Pinnacle, a sea stack some 450 feet (140 meters) long, 75 feet (23 meters) wide, and 110 feet (34 meters) tall. Temperatures average between 70 F and 80 F (21 C and 27 C) and the only vegetation is scattered salt grass. The reef forms an effective breakwater for ships anchored to its southwest, and the U.S. Navy was using the atoll as a seaplane anchorage and amphibious exercise site through the 1930s.

Japanese Flying Boat Operations. The Japanese twice attempted to reconnoiter and bomb Pearl Harbor using large flying boats refueled from submarines at French Frigate Shoals. The first attempt, on 5 March 1942 by two H8K Emily flying boats, encountered heavy overcast, was unable to observe the harbor, and dropped its bombs at random. They exploded harmlessly in the hills behind Pearl Harbor.

The second attempt was to have taken place in June 1942 as part of the Midway operation. It was foiled when Nimitz, tipped off by the code breakers, ordered a seaplane base set up at the atoll. This prevented the refueling rendezvous and left the Japanese guessing that the American carrier forces were still in port.

An emergency landing strip was built on Tern Island by the U.S. Navy in July 1942 by driving steel pilings around the island in a 3000 by 400 foot (910 by 120 meter) rectangle, dredging sand and coral into the enclosed area, and capping it with concrete. The strip looked very much like the deck of an aircraft carrier when seen from the air.

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