The Maritime Unit’s mission was to infiltrate agents and supply resistance groups by sea, conduct maritime sabotage, and to develop specialized maritime surface and subsurface equipment and devices. The Maritime Unit (MU) grew out of the Special Operations (SO) aquatic training requirement when it became apparent that the OSS needed a specialized amphibious capability. Marine Corps, Coast Guard, Navy, and Army personnel helped MU pioneer a special operations maritime capability.
The Maritime Unit operated in several theaters. In the Mediterranean, a fleet of hired Greek wooden fishing vessels—called caiques—covertly supported OSS agents in Albania, Greece, and Yugoslavia. After Italy surrendered, the MU and the San Marco battalion, an elite Italian special operations naval unit, operated against the Germans. In the Far East, the MU operated in conjunction with an Operational Group to attack Japanese forces on the Arakan coast of Burma. They jointly conducted reconnaissance missions on the Japanese-held coast, sometimes penetrating several miles up enemy-controlled rivers.
The MU was a special operations pioneer. In addition to being an early maritime warfare force, it developed or used several innovative devices, including an inflatable surfboard, a two-man kayak, and limpet mines that attached to the hull of a ship. Dr. Christian J. Lambertsen, then a U.S. Army captain, developed the Lambertsen Rebreathing Unit (LARU), an early underwater breathing device. The Lambertsen unit permitted a swimmer to remain underwater for several hours and to approach targets undetected because the LARU did not emit telltale air bubbles. The LARU was later refined, adapted, and the technology used by the U.S. Army, U.S. Navy, and NASA. The Army Special Forces Underwater Operations School at Key West, Florida, the home of Special Forces maritime operations, draws its roots from the Maritime Unit. Dr. Christian Lambersten is remembered today as the ‘Father of Military Underwater Operations.’