HMAS Larrakia (ACPB 84) is an Armidale class

Armidale class patrol boat

The Armidale class is a class of patrol boats built for the Royal Australian Navy . Planning for a class of twelve vessels to replace the fifteen Fremantle class patrol boats began in 1993 as a joint project with the Royal Malaysian Navy, but was cancelled when Malaysia pulled out of the process...

 patrol boat of 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).

Design and construction

The Armidale class patrol boats are 56.8 metres (186.4 ft) long, with a beam

Beam (nautical)

The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

 of 9.5 metres (31.2 ft), a maximum draft of 2.25 metres (7.4 ft), and a displacement

Displacement (ship)

A ship's displacement is its weight at any given time, generally expressed in metric tons or long tons. The term is often used to mean the ship's weight when it is loaded to its maximum capacity. A number of synonymous terms exist for this maximum weight, such as loaded displacement, full load...

 of 270 tons. The semi-displacement vee hull is fabricated from aluminium alloy, and each vessel is built to a combination of Det Norske Veritas

Det Norske Veritas

Stiftelsen Det Norske Veritas is a classification society organized as a foundation, with the objective of "Safeguarding life, property, and the environment". The organization's history goes back to 1864, when the foundation was established in Norway to inspect and evaluate the technical condition...

 standards for high-speed light craft and RAN requirements. The Armidales can travel at a maximum speed of 25 knots (13.6 m/s), and are driven by two propeller shafts, each connected to an MTU 16V M70 diesel. The ships have a range of 3000 nautical miles (5,556 km) at 12 knots (6.5 m/s), allowing them to patrol the waters around the distant territories of Australia

States and territories of Australia

The Commonwealth of Australia is a union of six states and various territories. The Australian mainland is made up of five states and three territories, with the sixth state of Tasmania being made up of islands. In addition there are six island territories, known as external territories, and a...

, and are designed for standard patrols of 21 days, with a maximum endurance of 42 days.

The main armament of the Armidale class is a Rafael Typhoon stabilised 25 millimetre (0.984251968503937 in) gun mount

Typhoon Weapon System

The Typhoon is a type of remote weapon station manufactured by Rafael Advanced Defense Systems of Israel, and it shares similar design principles and common technologies with Samson Remote Controlled Weapon Station , a land-based system manufactured by the same developer...

 fitted with an M242 Bushmaster

M242 Bushmaster

The M242 Bushmaster is a 25 mm chain-fed autocannon. It is used extensively by the US armed forces, as well as by NATO's and some other nations' forces in ground combat vehicles and watercraft...

 cannon. Two 12.7 millimetre (0.5 in) machine guns are also carried. Boarding operations are performed by two 7.2 metres (23.6 ft), waterjet propelled rigid-hulled inflatable boat

Rigid-hulled inflatable boat

A rigid-hulled inflatable boat, or rigid-inflatable boat is a light-weight but high-performance and high-capacity boat constructed with a solid, shaped hull and flexible tubes at the gunwale. The design is stable and seaworthy...

s (RHIBs). Each RHIB is stored in a dedicated cradle and davit

Davit

A davit is a structure, usually made of steel, which is used to lower things over an edge of a long drop off such as lowering a maintenance trapeze down a building or launching a lifeboat over the side of a ship....

, and is capable of operating independanly from the patrol boat as it carries its own communications, navigation, and safety equipment.

Each patrol boat has a standard ship's company of 21 personnel, with a maximum of 29. The Armidales do not have a permanently assigned ship's company; instead, they are assigned to divisions at a ratio of two vessels to three companies, which rotate through the vessels and allow the Armidales to spend more time at sea, without compromising sailors' rest time or training requirements. A 20-berth auxiliary accommodation compartment was included in the design for the transportation of soldiers, illegal fishermen, or unauthorised arrivals; in the latter two cases, the compartment could be secured from the outside. However, a malfunction in the sewerage treatment facilities aboard in August 2006 pumped hydrogen sulfide

Hydrogen sulfide

Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...

 and carbon monoxide

Carbon monoxide

Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...

 into the compartment, non-fatally poisoning four sailors working inside, after which use of the compartment for accommodation was banned across the class.

Larrakia was constructed by Austal

Austal

Austal is an Australian company that specializes in the design and construction of aluminium vessels. Its main products include passenger and freight ferries, luxury yachts and military vessels....

 at their shipyard in Henderson, Western Australia

Henderson, Western Australia

Henderson is a suburb of Perth, Western Australia, located within the City of Cockburn.-History:The suburb of Henderson comprises land resumed by the Commonwealth Government in 1915 for defence purposes. A large naval base was planned by Admiral Sir Reginald Henderson, and the was area sometimes...

. She was commissioned into the RAN in Darwin, Northern Territory

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...

 on 10 February 2006. Larrakia is named after the Larrakia

Larrakia

Larrakia are the Aboriginal Traditional Owners of Larrakia Country which includes the area in and around Darwin, Northern Territory in Australia...

Aboriginal peoples, and is the only Armidale not to be named after a regional city.

Operational history

Larrakia is assigned to Attack Division, is based in Darwin, and performs border protection and fisheries protection patrols.

External links

• HMAS Larrakia official website