HMAS Waterhen is a Royal Australian Navy (RAN) base located in on Sydney's lower north shore, within Sydney Harbour, in New South Wales, Australia. Constructed on the site of a quarry used to expand Garden Island in the 1930s, the location was used during World War II as a boom net maintenance and storage area. In 1962, the area was commissioned as a base of the RAN, and became home to the RAN's mine warfare forces. Waterhen was the first small-ship base established by the RAN, and from 1969 to 1979 was also responsible for the RAN's patrol boat forces. History Prior to the 1930s, the area on which Waterhen is constructed was a large hill overlooking Balls Head Bay. In the 1930s, the decision to construct a graving dock and landbridge connecting the naval base at Garden Island to the mainland at Potts Point led to the quarrying of this hill for sandstone, which altered the geography to a sheer cliff-face and near-water level plateau. The site was populated with fibro buildings during the leadup to World War II, and during the war was used to store spare netting for the Sydney Harbour anti-submarine boom net. The area was under military control from 15 March 1943 until the end of the war: the first three months under joint Royal Australian Navy-United States Navy control. The location reverted to a storage site after the conclusion of World War II, but in the early 1960s was earmarked as the future base for the RAN's minesweeping forces: six ex-Royal Navy s and a Clearance Diving Team, with the base commander to simultaneously hold overall command over these forces. Commissioned into the RAN as HMAS Waterhen (following the Royal Navy practice of treating naval bases as 'stone frigates') on 5 December 1962, Waterhen was the first 'small-ship' base to be established by the RAN. At commissioning, there were minimal facilities available: the River class frigate was relocated to the northern wharf in December 1952 and used as a barracks ship until June 1971. In March 1969, following the introduction of the of patrol boats, the base's role was expanded to include command of the RAN's patrol boat forces: the base commander held the position of Commander Australian Mine Warfare and Patrol Boat Forces. The command roles were split again in 1979, with the command of patrol boat forces relocated to in Queensland. The