Patrol from the second season onwards, with filming occurring aboard multiple ships of the class. Development and tendering Planning for the Armidale class began in 1993, as a plan to replace the , which was due for retirement in 1998. This evolved into a joint program with Malaysia to construct an offshore patrol craft. When Malaysia pulled out, the plan was scrapped, and the Fremantles underwent a life-extending refit. The cost of maintaining the aging vessels prompted the Department of Defence to create the Replacement Patrol Boat program, which received the procurement project designation SEA 1444. SEA 1444 marked several departures from the department's standard acquisition requirements. Instead of specifying a number of vessels, the coverage of 3,000 ship-days per year (with 1,800 to be spent on border protection operations, and a surge capability of 3,600 days) was given, with the producer to determine how many ships were needed to meet this. The ships had to meet specific performance parameters, such as the ability to conduct boarding operations in conditions up to Sea State 4, and to maintain surveillance capability up to Sea State 5. The producer was also required in the contract to provide support and maintenance for the ships, for fifteen years after construction completed. Nine companies expressed interest in the project; of these, seven had the required capability to build the ships. These seven were narrowed down to three based on each tender's merit, competitiveness with the other tenders, and successful meeting of Australian industry involvement targets for both construction and long-term support. Austal and Defence Maritime Services (DMS) partnered to offer twelve ships based on an expanded version of the latter's , in use with the Australian Customs Service. The companies submitted two proposals for a vessel, one with a steel hull, and one with an aluminium hull; the latter offering a 21% reduction in fuel consumption. Australian Defence Industries (ADI) tendered a design based on the Royal Danish Navy's . The vessel was to be built with a glass-reinforced plastic hull, similar to ADI's s. The Tenix proposal was a variant of a search and rescue vessel constructed for the Philippine Coast Guard. The tender was awarded to the Austal/DMS partnership in December 2003.Ships Announced as Prefered Tenderer for Royal Australian Navy Patrol Boats Austral 29 August 2003 The contract was valued at $553 million, with each ship costing between $24 million and $28 million