Leeuwin-class survey vessel

The Leeuwin class is a two-ship class of hydrographic survey vessels operated by the Royal Australian Navy (RAN). HMAS Leeuwin (A 245) and HMAS Melville (A 246) were ordered from NQEA in 1996, and were commissioned in 2000. The ships are capable of charting waters up to 6,000 m deep, carry three Fantome class survey boats, and can operate an AS 350B Squirrel helicopter. In addition to surveying duties, since 2001 both vessels have been used to supplement the RAN patrol force. Leeuwin and Melville are based at HMAS Cairns (naval base), and are active as of 2012.

Design and construction
The ships have a displacement of 2,170 tons at full load. They are 71.2 m long, with a beam of 15.2 m, and a draught of 4.3 m. Main propulsion machinery consists of four GEC Alsthom 6RK 215 diesel generators, which supply two Alsthom electric motors, each driving a propeller shaft. A Schottel bow thruster is fitted for additional manoeuvrability. Maximum speed is 18 kn, with a range of 18,000 nmi at 9 kn.

Each ship is fitted with a STN Atlas 9600 APRA I-band navigational radar. The vessels are fitted with a C-Tech CMAS 36/39 hull-mounted high-frequency active sonar. In addition, the ships carry an Atlas Fansweep-20 multibeam echo sounder and an Atlas Hydrographic Deso single-beam echo sounder, and a Klein 2000 towed sidescan sonar array. The sonars and echo sounders allow the vessels to chart waters up to 6,000 m deep. There are three sets of davits fitted; although normally used to carry the 10.7 m Fantome class survey boats, they can be configured for other small craft. In addition, they carry a RHIB and two utility boats. The Leeuwins are fitted with a helicopter deck for an AS 350B Squirrel helicopter (detached from 723 Squadron), although lack long-term hosting facilities. They are armed with two single 12.7 mm machine guns.

The ship's company consists of 10 officers and 46 sailors. In addition, up to 5 trainees can be accommodated. The Leeuwins were the first RAN ships to use a multi-crewing concept, with three complements used to operate the two vessels.

The two ships were ordered from NQEA on 2 April 1996, and built at the company's shipyard in Cairns, Queensland. Construction of HMAS Leeuwin (A 245) commenced in August 1996, and she was launched in July 1997, while HMAS Melville (A 246) was laid down in May 1997 and launched in June 1998. The vessels underwent a joint commissioning ceremony on 27 May 2000. The ships initially bore the pennant numbers "HS 01" and "HS 02" respectively, but these were changed in 2004 to "A 245" and "A 246".

Operational history
Both Leeuwin and Melville are based at HMAS Cairns (naval base). They operate in support of the Australian Hydrographic Office.

In late 2001, both ships began operations to supplement patrol forces and counter illegal immigration as part of Operation Relex, in addition to normal surveying duties. The survey ships were selected as they had greater range and seakeeping capabilities that the Fremantle class patrol boats. In January 2002, Leeuwin and Melville were repainted from white to grey.