HMAS Jervis Bay (AKR 45)

The ship's first period of service was on charter to TT-Line, for service between Melbourne, Victoria and Devonport, Tasmania. Named Tascat, the ship ran in conjunction with the first Spirit of Tasmania until the new ferries Spirit of Tasmania I and Spirit of Tasmania II entered service, at which point she was laid up.

After an increase in instability in nations near Australia, the Australian Defence Force sought to upgrade a second brigade-size group to activation on short notice.[3] Delays in refitting the two Kanimbla class vessels acquired from the United States Navy several years earlier meant that the RAN's sealift capability had to be supplemented in order to support two brigades.[3] The RAN sought a large, high-speed catamaran from either Incat or Australian Ships (later named Austal): both companies had vessels available, but only Incat was able to provide a ship before June 1999.[3] A two-year bareboat charter was signed for Incat 045 in May 1999, and the vessel was commissioned into the RAN as HMAS Jervis Bay on 10 June 1999.[2][3]

For military service, the catamaran was modified with enlarged fuel tanks to extend her range to 1,000 nautical miles (1,900 km; 1,200 mi) and additional air conditioning units to improve equipment operational reliability in tropical climates.[3] Sections of the vehicle deck were reinforced to support up to nine tons of weight per axle, allowing the vessel to transport most Australian Army vehicles.[3] The catamaran's vehicle ramp was modified so it could be self-deployed, instead of requiring dock facilities.[3] After modification, Jervis Bay could transport 500 troops, plus their equipment, supplies, and vehicles.[1] In order to maintain a high operational tempo without personnel fatigue or burnout, two ships' companies of 20 (including five Army personnel responsible for the embarcation, storage, and disembarcation of Army personnel and equipment) were established;[3] a practice later used by the RAN on patrol boats and survey ships. Because Jervis Bay was designed for short-haul voyages, crew and passenger facilities were limited: little potable water was carried, cooking facilities were minimal, and there were no sleeping facilities for the crew.[3] Later modifications included the installation of additional water tanks, and the fitting of 20 bunks.[3]

HMAS Jervis Bay in Dili in October 1999

Based in Darwin after commissioning, Jervis Bay was in a fortuitous position to respond to the 1999 East Timorese crisis, and was used to provide logistic support to the Australian-led INTERFET peacekeeping taskforce.[3] The catamaran was the first RAN ship to reach Dili; deploying 3RAR to the city's damaged docks on 12 September.[3][4] Jervis Bay was then used to transport soldiers and equipment between Darwin and Dili: she was capable of sailing the 430 nautical miles (800 km; 490 mi) in around 11 hours[5] at an average speed of approximately 45 knots (83 km/h; 52 mph).[1][3] The catamaran was also used to transport humanitarian aid, and relocate displaced persons.[3]

During the two years of the ship's charter by the RAN, Jervis Bay made 107 trips between Darwin and East Timor, shipping 20,000 passengers, 430 vehicles and 5,600 tonnes of freight, becoming known as the "Dili Express".[6][7] Running the catamaran was found to be more efficient than using air transport to move materiel to and from East Timor, with the higher sailing speed meaning she could turn around a payload faster than multiple C-130 Hercules flights for an equivalent load.[8]

In March 2010, the ship was retroactively awarded the battle honour "East Timor 1999–2000".[9][10]

The successful use of a catamaran in military logistics operations led to the acquisition of three Incat catamarans by the United States military (Joint Venture (Incat 050), Spearhead (060), and Swift (061))[11] and prompted the development of the Independence class littoral combat ships as trimarans.