| HMASWaterhen | |
|---|---|
| Part ofFleet Base East | |
| Waverton, New South Wales in Australia | |
 HMASWaterhen | |
| Site information | |
| Type | Naval base |
| Owner | Department of Defence |
| Operator |  Royal Australian Navy (1943–1967); Royal Australian Navy (1967 – present) |
| Location | |
  HMASWaterhen Location inGreater Sydney | |
| Coordinates | 33°50′28″S151°11′40″E / 33.84111°S 151.19444°E /-33.84111; 151.19444 |
| Site history | |
| In use | 1943 – present |
| Garrison information | |
| Current commander | Lieutenant Commander Lucy Frauenfelder, RAN |
| Past commanders | Commander Fiona Eggins, RANCommander David Jones, RAN |
HMASWaterhen is aRoyal Australian Navy (RAN)base located inWaverton onSydney'slower north shore, withinSydney Harbour, inNew South Wales, Australia. Constructed on the site of a quarry used to expandGarden Island in the 1930s, the location was used during World War II as a boom net maintenance and storage area. In 1962, the area wascommissioned 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'spatrol boat forces.
Prior to the 1930s, the area on whichWaterhen is constructed was a large hill overlookingBalls Head Bay. In the 1930s, the decision to construct a graving dock and landbridge connecting the naval base atGarden Island to the mainland atPotts 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 withfibro buildings during the leadup to World War II, and during the war was used to store spare netting for theSydney 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 jointRoyal Australian Navy-United States Navy control.[1]
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 NavyTon-class minesweepers and aClearance Diving Team, with the base commander to simultaneously hold overall command over these forces. Commissioned into the RAN as HMASWaterhen (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.[1] At commissioning, there were minimal facilities available: theRiver class frigateHMAS Culgoa was relocated to the northern wharf in December 1952 and used as abarracks ship until June 1971.[2]
In March 1969, following the introduction of theAttack class 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 toHMAS Cairns in Queensland.[1] The 1980s saw an attempted upgrade to the minesweeper fleet with the development of theBay-class minehunters, with the first two ships of the class, HMA ShipsRushcutter andShoalwater assigned toWaterhen.[3]: 222 TheBays did not enter service until 1993, and problems with their sonar andseakeeping ability saw the other four ships of the class cancelled and forced the RAN to rely on a force of minesweeper auxiliariesconverted from acquired civilian vessels and also based atWaterhen until the development of theHuon-class minehunters in the late 1990s.[3]: 275
In 1994, the same year theHuon class project began, it was recognised by the RAN that the facilities at Waterhen needed to be upgraded. Over a period from December 1994 to December 1996, the entire base was levelled, with new buildings, wharves, and facilities installed. The upgrade cost A$70 million and was completed eight months ahead of schedule.[1]
As of 2025,Waterhen is home to the Australian Navy Mine Warfare and Clearance Diving Group, which consists of:[1]
In addition, with the introduction of the Canberra-class Landing Helicopter Dock into the RAN, the ships associated Landing Craft have been based there, since their introduction in 2014.
Maintenance and the training program for the crews to operate the craft is also housed at the base.
Waterhen is also used as a base for minor war vessels visiting or operating temporarily from Sydney.
The first season of the television drama seriesSea Patrol, which was primarily set on aFremantle-class patrol boat, was filmed atWaterhen and the base was used to represent a fictional Australian naval base.Waterhen was used for the filming of several 'ashore' scenes, and was host to the decommissionedHMAS Wollongong, which was used to film scenes of the patrol boat docked at base.
