The Leeuwin class is a class of two hydrographic

Hydrography

Hydrography is the measurement of the depths, the tides and currents of a body of water and establishment of the sea, river or lake bed topography and morphology. Normally and historically for the purpose of charting a body of water for the safe navigation of shipping...

 survey vessels in the Royal Australian Navy

Royal Australian Navy

The Royal Australian Navy is the naval branch of the Australian Defence Force. Following the Federation of Australia in 1901, the ships and resources of the separate colonial navies were integrated into a national force: the Commonwealth Naval Forces...

, HMAS Leeuwin and HMAS Melville

HMAS Melville (A 246)

HMAS Melville is the second ship of the Leeuwin class of hydrographic survey vessels of the Royal Australian Navy . Melville is named after Melville Island to the north of Darwin, Northern Territory...

. Both ships were built by NQEA in Cairns, Queensland

Cairns, Queensland

Cairns is a regional city in Far North Queensland, Australia, founded 1876. The city was named after William Wellington Cairns, then-current Governor of Queensland. It was formed to serve miners heading for the Hodgkinson River goldfield, but experienced a decline when an easier route was...

, and entered service in 2000.

Both ships take their names from prominent points on the Australian coast: Leeuwin is named after Cape Leeuwin

Cape Leeuwin

Cape Leeuwin is the most south-westerly mainland point of the Australian Continent, in the state of Western Australia.A few small islands and rocks, the St Alouarn Islands, extend further to the south. The nearest settlement, north of the cape, is Augusta. South-east of Cape Leeuwin, the coast...

, on the South West tip of Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

 while Melville is named after Melville Island

Melville Island, Northern Territory

Melville Island or Yermalner Island lies in the eastern Timor Sea, off the coast of the Northern Territory of Australia. It is west of the Cobourg Peninsula in Arnhem Land and north of Darwin....

, just to the north of Darwin

Darwin, Northern Territory

Darwin is the capital city of the Northern Territory, Australia. Situated on the Timor Sea, Darwin has a population of 127,500, making it by far the largest and most populated city in the sparsely populated Northern Territory, but the least populous of all Australia's capital cities...

.

The ships have the ability to support an AS 350B Squirrel helicopter (detached from 723 Squadron

723 Squadron RAN

723 Squadron is a Royal Australian Navy Fleet Air Arm squadron.-History:723 Squadron was first commissioned into the RAN on 7 April 1952 and was equipped with one Dakota, one Wirraway, one Sea Otter and two Sea Fury aircraft...

), and carry three Fantome class survey motor boats

Fantome class survey motor boat

The Fantome class survey motor boat is a class of eight small boats operated by the Royal Australian Navy and DMS Maritime. The four-man survey boats are designed to operate from the Leeuwin class survey vessels, with three assigned to each ship, while the seventh and eighth were attached to the...

.

Both ships are based at the naval base HMAS Cairns

HMAS Cairns (naval base)

HMAS Cairns is a naval base of the Royal Australian Navy located in Cairns, Queensland. Although used regularly as a port-of-call since before World War II, a permanent RAN presence was not established until 1971, when a maintenance and support base for patrol boats was set up...

 in Cairns, Queensland

Cairns, Queensland

Cairns is a regional city in Far North Queensland, Australia, founded 1876. The city was named after William Wellington Cairns, then-current Governor of Queensland. It was formed to serve miners heading for the Hodgkinson River goldfield, but experienced a decline when an easier route was...

. Leeuwin and Melville are crewed using a flexible arrangement in which three crews rotate between the two ships. The three crews are known as HS (Hydrographic Ship) White, Red and Blue crews.