after whom the Naval Special Warfare Command building is named, and NCDU 3 under LTjg Lloyd Anderson, formed the nucleus of six NCDUs that served with the Seventh Amphibious Force tasked with clearing boat channels after the landings from Biak to Borneo. OSS Operational Swimmers Some of the earliest World War II predecessors of the SEALs were the Operational Swimmers of the Office of Strategic Services, or OSS. Many present day SEAL missions were first assigned to them. The OSS specialized in special operations, dropping operatives behind enemy lines to engage in organized guerrilla warfare as well as to gather information on such things as enemy resources and troop movements. British Combined Operations veteran Lt Cdr Wooley, of the Royal Navy, was placed in charge of the OSS Maritime Unit in June 1943. Their training started in November 1943 at Camp Pendleton, California, moved to Santa Catalina Island, California in January 1944, and finally moved to the warmer waters of The Bahamas in March 1944. Within the U.S. military, they pioneered flexible swimfins and diving masks, closed-circuit diving equipment (under the direction of Dr. Chris Lambertsen), the use of Swimmer Delivery Vehicles (a type of submersible), and combat swimming and limpet mine attacks. In May 1944, General Donovan, the head of the OSS, divided the unit into groups. He loaned Group 1, under Lieutenant Arthur Choate, Jr., to Admiral Nimitz, as a way to introduce the OSS into the Pacific theater. They became part of UDT-10 in July 1944, with Lt. Commander Choate commanding the unit. Five OSS men participated in the very first UDT submarine operation with the in the Caroline Islands in August 1944. Beach Jumpers Beach Jumper Unit One was formed at the Amphibious Training Base at Camp Bradford, Virginia on 16 March 1943 for deception operations to simulate large scale amphibious raids and invasions. Underwater Demolition Teams On 23 November 1943, the U.S. Marine landing and the subsequent battle at Tarawa Atoll emphasized the need for hydrographic reconnaissance and underwater demolition of obstacles prior to any amphibious landing. After Tarawa, 30 officers and 150 enlisted men were moved to the Waimānalo Amphibious Training Base to form the nucleus of a demolition training program. This group became Underwater Demolition Teams (UDT) One and Two. The UDTs saw their first combat on 31 January 1944, during Operation Flintlock in the Marshall Islands. FLINTLOCK became the real catalyst for