In the Persian Gulf the Oman Navy has bought two HSSV catamaran (twin hull) high speed transports from the Australian firm (Austal) that pioneered the design. Austal has been selling similar vessels to the U.S. Navy for over a decade. The HSSV is a 72 meter (234 feet) long ship that can carry 320 tons of cargo and up to 250 passengers. Top speed is 63 kilometers an hour and the vessel is operated by a crew of 69. Oman had already been using another version of this vessel as commercial ferries and the navy was impressed with their performance. The Omani Navy was also familiar with the American experience with this type of ship.
Meanwhile, five years after ordering production to start, the U.S. Navy received the first of ten Joint High Speed Vessels (JHSV) transports in 2013. These 103 meter (320 feet) long, $160 million ships are refined versions of the earlier HSV 2 ship developed for the U.S. Army. The army already had leased two of these HSVs and the navy another. Good performance of these led to the JHSV. The manufacturing of the JHSVs is being done by an Australian firm in the U.S. All ten should be in service by 2017. The army and the navy are seeing a more urgent need for these ships, which can quickly move troops, supplies, and equipment around locally.
All this began in 2001 when the U.S. Navy began leasing a high speed (60 kilometers an hour) catamaran, the Westpac Express, from an Australian firm, to move U.S. Marine Corps equipment around the Pacific. In this it was very successful, and this has served to prove the ability of such a catamaran design to serve in a military role.
This led to a new class (HSV or High Speed Vessel) of transport ships. In 2003, the navy leased an improved design, to further test the concept. The USS Swift (HSV 2) was a twin hulled catamaran, designed and built in Australia. Based on that very successful experience with the Westpac Express, many modifications were made and the Swift was built in ten months. The design was modified so the HSV 2 could perform both transport and mine sweeping missions. The HSV is actually a small ship, 103 meters long and displaces 1,600 tons. It can carry up to 600 tons of cargo and has airline style seating for 300 troops, although up to 600 can be carried for short periods. The cargo can include vehicles of up to 70 tons each, including M-1 tanks. Vehicles are driven on and off. There is a tradeoff between tonnage carried and speed and range. The twin hull design is also slowed down quite a bit in rough seas. This is not the kind of ship you can use much in the North Atlantic or North Pacific.
There is also a helicopter pad and space for two UH-60 or CH-46 class choppers. The basic crew is only 41, but there are crew quarters for 51 and the galley can feed up to 150. The important aspect of the HSV is speed. The Swift maintained a speed of 83 kilometers an hour for four hours during sea trails. The ship can cruise at 63 kilometers an hour for 2,000 kilometers, or 7,200 kilometers at 36 kilometers an hour before it has to be refueled. The HSV has four water-jets, making it very maneuverable. The Swift is going to be used mainly as a mine warfare support ship but additional HSVs will serve as high speed transports. Weapons can include manned 25mm automatic cannon and remote controlled 12.7mm machine-gun or 40m grenade launchers.
The HSSV is optimized for the calmer waters of the Persian Gulf and the shorter distances over which the Omani Navy will be operating it, compared to what the U.S. Navy required for the Western Pacific. Oman has a long coastline (over 2,000 kilometers) and most Omanis live near the coast. So the HSSV is an effective way to get troops, relief supplies or whatever around.