* The Royal Navy maintains a squadron at the Rock. The squadron is responsible for the security and integrity of British Gibraltar Territorial Waters (BGTW). The shore establishment at Gibraltar is called HMS ''Rooke'' after Sir George Rooke, who captured the Rock for Archduke Charles (pretender to the Spanish throne) in 1704. The naval air base was named HMS ''Cormorant.'' Gibraltar's strategic position provides an important facility for the Royal Navy and Britain's allies. British and US nuclear submarines frequently visit the ''Z berths'' at Gibraltar. A Z berth provides the facility for nuclear submarines to visit for operational or recreational purposes and for non-nuclear repairs. During the Falklands War, an Argentine plan to attack British shipping in the harbour using frogmen (Operation Algeciras) was foiled. The naval base also played a part in supporting the task force sent by Britain to recover the Falklands.