The Huon class Minehunter Coastal (MHC) ships are a group of minehunter

Minehunter

Minehunters are mine countermeasure vessels that actively detect and destroy individual naval mines. Minesweepers, on the other hand, clear mined areas as a whole, without prior detection of mines...

s built for 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...

 (RAN). Following problems with the Bay class minehunter

Bay class minehunter

The Bay class Minehunter Inshores were a class of catamaran-hull mine warfare vessels operating with the Royal Australian Navy from 1986. Also referred to as the MHCAT , the class was an attempt to produce a locally designed inshore mine warfare vessel. Two prototype ships were ordered in 1981,...

s, a request for tender

Request for tender

A request for tender, commonly abbreviated to RFT, is a formal, structured invitation to suppliers for the supply of products or services. In the public sector, such a process may be required and determined in detail by law to ensure that such competition for the use of public money is open, fair...

 was issued in 1993 for a class of six coastal minehunters under the project designation SEA 1555. The tender was awarded in 1994 to the partnership of Australian Defence Industries

Australian Defence Industries

Thales Australia is a primary defence contractor for the Australian Defence Force. Thales Australia is best known for its naval ship repair operations, and currently leases the Captain Cook graving dock at Garden Island Naval Base in Sydney, New South Wales and also leases and occupies many of the...

 (ADI) and Intermarine SpA, which was offering a variant of the Italian Gaeta class minehunter.

Five of the six ships were constructed completely in Newcastle, New South Wales

Newcastle, New South Wales

The Newcastle metropolitan area is the second most populated area in the Australian state of New South Wales and includes most of the Newcastle and Lake Macquarie Local Government Areas...

, while the hull of the first ship was built in Italy, then transported to Australia for fitting out. Construction ran from 1994 to 2003, with lead ship entering service in 1999. All six vessels are based at , in Sydney. In 2006, following a capability review three years prior, one minehunter was placed in reserve, while another was marked for transfer to reserve status; this instruction was reversed prior to 2008, and the two vessels were tasked with supporting border protection operations.

As of October 2011, only four vessels were active, with the other two placed in reserve.

Development and tendering

In 1993, the Department of Defence issued a request for tender for six coastal minehunters to replace the problematic Bay class minehunter

Bay class minehunter

The Bay class Minehunter Inshores were a class of catamaran-hull mine warfare vessels operating with the Royal Australian Navy from 1986. Also referred to as the MHCAT , the class was an attempt to produce a locally designed inshore mine warfare vessel. Two prototype ships were ordered in 1981,...

s, of which four had been cancelled after the first two demonstrated problems with their sonar array and seakeeping capability. According to an article in Jane's International Defence Review published just before the tender was opened, three joint ventures between an Australian and a European company were expected to submit designs: Australian Defence Industries

Australian Defence Industries

Thales Australia is a primary defence contractor for the Australian Defence Force. Thales Australia is best known for its naval ship repair operations, and currently leases the Captain Cook graving dock at Garden Island Naval Base in Sydney, New South Wales and also leases and occupies many of the...

 (ADI) and Intermarine SpA with the Gaeta class, Australian Submarine Corporation

Australian Submarine Corporation

The ASC, formerly Australian Submarine Corporation, is a wholly government-owned Australian naval defence company headquartered at Osborne in Adelaide, South Australia.-History:...

 and Karlskronavarvet (later Kockums

Kockums

Kockums AB is a shipyard in Malmö, Sweden owned by the German shipyard Howaldtswerke-Deutsche Werft in Kiel. HDW itself is a subsidiary of the German ThyssenKrupp Marine Systems....

) with a lengthened version of the Landsort class

Landsort class mine countermeasures vessel

The Landsort class mine countermeasures vessel is built by Swedish shipbuilding company, Kockums for the Swedish Navy and the Republic of Singapore Navy .-Design:...

, and AMECON

AmeCon

AmeCon is an anime convention based in Leicester, United Kingdom, typically of three days in length, and is one of the largest anime conventions in the United Kingdom. The convention was formed after several committee members of the Leicester Anime and Manga Club decided to run a small,...

 and Vosper Thornycroft with the Sandown class

Sandown class minehunter

The Sandown class is a class of minehunter originally built for the British Royal Navy). Sandown-class vessels also serve with the Royal Saudi Navy and the Estonian Navy...

. According to the request for tender, the designs had to be modified to operate in Australian conditions, and at least 60% of each ship and her equipment had to be of Australian manufacture.

On 12 August 1994, Project SEA 1555 was awarded to ADI.

Design and construction

The design of the Huon class is based on the Italian Lerici class

Lerici class minehunter

The Lerici class is a class of minehunters constructed by Intermarine SpA and owned and operated by the Marina Militare, the Italian Navy...

; specificly the second run of eight ships known as the Gaeta class. Each ship has a full load displacement of 720 tons, is 52.5 metres (172.2 ft) long, has a beam of 9.9 metres (32.5 ft), and had a draught of 4.87 metres (16 ft): a slighly greater draught and displacement than the Gaetas. The minehunters main propulsion system is a single Fincantieri GMT BL230-BN diesel motor, which provides 1985 bhp to a single controllable pitch propeller

Controllable pitch propeller

A controllable pitch propeller or variable pitch propeller is a type of propeller with blades that can be rotated around their long axis to change their pitch...

, allowing the ship to reach 14 knots (7.6 m/s). Maximum range is 1500 nautical miles (2,778 km) at 12 knots (6.5 m/s), with a 30% fuel reserve, and the vessels have an endurance of 19 days. The standard ship's company consists of 6 officers and 33 sailors, plus up to 13 trainees or 6 divers. The main armament on a Huon is a MSI DS30B 30 mm cannon; this is supplemented by two 0.50 calibre machine guns. The sensor suite includes a Kelvin-Hughes Type 1007 navigational radar, a Thompson-Marconi Type 2093M variable-depth minehunting sonar, an AWA Type 133 PRISM radar warning and direction-finding system, and a Radamec 1500 surveillance system. Two Wallop Super Barricade decoy launchers are also fitted.

For minehunting operations, the Huons use three 120 hp Riva Calzoni azimuth thruster

Azimuth thruster

An azimuth thruster is a configuration of ship propellers placed in pods that can be rotated in any horizontal direction, making a rudder unnecessary...

s to provide a maximum speed of 6 knots (3.3 m/s): two are located at the stern, while the third is sited behind the variable-depth sonar. Mines are located with the minehunting sonar, and can be disposed of by the vessel's two Double Eagle mine disposal vehicles

Double Eagle (mine disposal vehicle)

The Double Eagle is a remotely operated vehicle built by the Swedish defence company Saab Underwater Systems AB and used for the disposal of naval mines.-Design:As of 2009, four versions of the ROV have been designed....

, the Oropesa mechanical sweep, the Mini-Dyad magnetic influence sweep, or the towed AMASS influence sweep (which is not always carried). To prevent damage in the event a Huon class ship triggers a mine, the ships were built with a glass-reinforced plastic

Glass-reinforced plastic

Fiberglass , is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass. It is also known as GFK ....

, moulded in a single monocoque

Monocoque

Monocoque is a construction technique that supports structural load by using an object's external skin, as opposed to using an internal frame or truss that is then covered with a non-load-bearing skin or coachwork...

 skin with no ribs or framework. The ships often work with clearance divers, and are fitted with a small recompression chamber.
Six Huon class ships built in total; all were named after famous Australian rivers (the names of which had been carried by previous RAN vessels). The hull of the lead ship, , was laid down during September 1995 at the Intermarine SpA Sarzana shipyard in Italy, and was transferred out to ADI's Newcastle facility as deck cargo, arriving on 31 August 1995. Huon was completed in Newcastle in 1999, and the other five ships were constructed completely at the Australian shipyard. All six were completed on schedule, with the last, , commissioning on 1 March 2004.

Operational history

All six vessels are based at , which serves as the home base of the Mine Warfare and Clearance Diving Group.

As part of the force structure changes arising from the 2003 Defence Capability Review two Huon class ships were deactivated and placed in reserve. HMAS Huon was deactivated in early 2006, but was reactivated later in the year, while HMAS Hawkesburys planned deactivation was cancelled so the ships could be used as patrol boats. As of 2008, Huon and Hawkesbury were taking turns supporting border security operations. However, by October 2011, both vessels had been placed into reserve, and the Australian Department of Defence predicted that it would take five years to bring both back to operational status and train personnel to run the vessels.