Arafura-class offshore patrol vessel

First made public in Defending Australia in the Asia Pacific Century: Force 2030, the 2009 Department of Defence white paper, the planned vessels stem from Government instructions for the RAN to rationalise patrol, mine warfare, and hydrographic survey assets into a single class of warship.[12] It was originally planned 20 OCVs would replace 26 vessels across four separate ship classes: the Armidale-class patrol boats, the Huon-class minehunters, the Leeuwin-class survey vessels, and the Paluma-class survey motor launches

Instead of being capable of performing all roles simultaneously, the ships will have a modular mission payload system like the Standard Flex system used by the Danish Navy, or the system used by the United States Navy's littoral combat ships: mission-specific equipment will be fitted to containerised modules, which can be exchanged for different modules when the ship needs to change roles.[12][13][14] The use of containerised modules means that equipment can be upgraded without taking the ships out of service for refit, and if necessary can be fitted to requisitioned civilian vessels.[15] The cost in developing and implementing the modular system is predicted to be offset by the savings in the areas of maintenance (having to purchase and maintain stocks to repair four different designs), personnel (having to retrain sailors when they transfer to a new ship), and administration.[12][15]

The Paluma-class survey motor launch HMAS Benalla (left) and the Huon-class minehunter HMAS Gascoyne: two of the four ship classes were to be replaced by the Offshore Combatant Vessel

It was anticipated that the new ships could have displaced anywhere up to 2,000 tonnes, although defence magazine editor Kym Bergmann predicts that this 'worst case' would require 50,000 tons of steel or aluminium to be fabricated (compared to 36,000 tons for the Attack-class submarine program), and unless multiple shipbuilders are involved, the 12- to 18-month construction time per vessel will see the last ship enter service during the late 2020s.[12][16]

Instead of building all 20 vessels to the same design, the idea of hull variants optimised for different roles is also being explored:[15] the module system will allow a ship designed for one role to be rapidly reconfigured to serve in another role, with a small but acceptable loss in capability compared to a 'native' OPV. The OPVs could be designed to carry a helicopter or an unmanned aerial vehicle to improve each ship's surveillance range, but this avenue is dependent on further study and cost-benefit analysis.[12][17]

The OPV was originally planned to replace 26 vessels across four warship classes: the Armidale-class patrol boats, the Huon-class minehunters, the Leeuwin-class survey vessels, and the Paluma-class survey motor launches.[12][18] The new ships were to be used for offshore and littoral patrol, border protection, anti-terrorism and anti-piracy operations, mine warfare, and hydrographic survey.[12] It was plausible that the OPVs will operate in support of the Canberra-class landing helicopter dock ships; amphibious operations would benefit from the survey and mine warfare capabilities of the ships.[17]

Another major change, reportedly being examined by the DSR (Australia's Defence Strategic Review), is the possibility of either up-arming or divesting the service's new Arafura-class OPVs, before NUSHIP Arafura has even conducted sea trials. The concern is that the OPVs are not able to contribute to any high-end scenarios, as they lack so much as a large calibre gun. One possibility, being examined, is outfitting the vessels with between four and six Kongsberg Naval Strike Missiles, which the RAN is already procuring. Another approach, which has gained some traction, is the possibility of divesting the fleet to other government agencies (such as the Australian Border Force) and international partners (such as Papua New Guinea), and instead procuring a fleet of missile-armed corvettes.

The Royal Navy has begun plans for a similar vessel under the Future Surface Combatant program, designated the Future Mine Countermeasures/Hydrographic/Patrol Vessel (FMHPV).[19] At the start of 2010, it was announced that the governments of Australia and the United Kingdom were exploring the potential for idea-sharing and co-operation on the design of the OPV and FMHPV, as well as planned replacements for the Anzac-class, Type 22, and Type 23 frigates.[19] Although the nations will share their analyses, a common design or shared construction program is unlikely, as the two nations have different needs and replacement schedules.[15][19] The RAN is also observing the development of the United States Navy Littoral Combat Ships, to take advantage of lessons learned during the program.[15]

Austal suggested a scaled-down variant of the Independence-class littoral combat ship (USS Coronado pictured) for the Australian OCV project

While designing the Independence-class trimarans for the Littoral Combat Ship program, Australian-owned shipbuilder Austal also prepared a scaled-down version that could serve as the basis for the Australian OPV.[16] The Austal Multi Role Vessel (MRV 80) would have an overall length of 80 metres, a top speed of 26 knots, carry an NH-90 or similar helicopter, and have 500 square metres for mission equipment or cargo.[20]

In 2012, American shipbuilder Huntington Ingalls Industries proposed a variant of the Legend-class National Security Cutter, a ship built for the United States Coast Guard.[21]

The Arafura-class is based on the Lürssen-designed Darussalam-class, operated by the Royal Brunei Navy.[1] Each vessel has a gross displacement of 1,640 tonnes, and measures 80 metres long, with a beam of 13 metres and a draft of 4 metres.[1] Propulsion power is from two MTU 16V diesel engines rated at 4440kW each, which drive variable pitch propellers and give a top speed of 22 knots, and shipboard electrical power is generated by MAN diesel engines.[1] The ship's range is about 4,000 nautical miles (7,400 km), with an endurance of 21 days.[1] The standard crew complement is 40 sailors, though up to 20 more can be berthed if required.[1] The ships will be deployed with empty space available to install container-mounted systems such as aircraft support and sensors; if fully utilized, the gross displacement could increase to 1,800 tonnes.[1]

Shipboard armament was originally intended to be a single 40 mm gun and two 12.7 mm guns.[1] The 40 mm gun was cancelled in 2021 due to a combination of technical problems and a re-assessment of the threats the ships would face. The ships will instead be armed with a Typhoon Weapon Station on an interim basis until a replacement weapon is identified and then acquired.[27] In May 2023 it was reported that the RAN was considering purchasing a containerised variant of the C-Dome surface to air missile system to improve the Arafura-class's armament.[28]

Each vessel carries two 8.5 metre rigid inflatable boats and a single 10 metre boat, which are intended as the primary means of deploying offensive force in the ships' border patrol role.[1] A single unmanned aerial vehicle is carried and deployed from an open utility deck.[1] Two separate electro-optic targeting systems and three radars are installed and managed by the Saab 9LV system.[1] In order to allow the ships to operate in conjunction with allied international forces, each ship is equipped with a unique electronic identifier transponder that allows for communication via the Link 16 network.[1]