Underwater demolition refers to the deliberate destruction or neutralization of man-made or natural underwater obstacles, both for military and civilian purposes.
In 1839 Charles Pasley, a colonel of the Royal Engineers, used sealed barrels of gunpowder to demolish the wreck of the Royal George, which sank at moorings at Spithead in 1782.
Shortly after the American Civil War, Brevet Maj. Gen. John G. Foster, a West Point trained engineer, became one of the first acknowledged experts in underwater demolition. In 1869, he wrote a definitive treatise on the topic and became widely recognized as the authority on underwater demolition. Many of his theories and techniques were still in practice during the Spanish–American War and World War I.
In 1940, Christian J. Lambertsen demonstrated his semi-closed circuit rebreather, the Lambertsen Amphibious Respiratory Unit (LARU), for the U.S. Navy in connection with his proposal for the formation of military teams of underwater swimmers.
Major Lambertsen served in the U.S. Army Medical Corps from 1944 to 1946 where he did a detached service in underwater operations with the Office of Strategic Services (OSS). After joining OSS, he was vital in establishing the first cadres of U.S. military operational combat swimmers during late World War II.
His responsibilities included training and developing methods of combining self-contained diving and swimmer delivery for the OSS "Operational Swimmer Group". Following World War II, he trained U.S. forces in methods for submerged operations, including composite fleet submarine / operational swimmers activity.
In June 1943, Draper L. Kauffman organized the first U.S. Navy Demolition Teams. The original purpose of these teams was to map and record conditions in amphibious landing zones and to demolish obstacles in water which would prevent vehicles from landing during invasions. Underwater demolition specialists may still be referred to as underwater demolition teams. Today, various special operations units use aspects of demolition diving. Most prominently carried out by Navy SEALs and UCT divers.