Last year, the U.S. Navy and the Army set up a deal where they would jointly buy a fleet of ten new Joint High Speed Vessels (JHSV) transports. These 320 foot long, $160 million ships are refined versions of the earlier HSV 2 ship. The army already has two of these HSV 2s, and the navy has one. The manufacturing of the JHSVs is being set up, by an Australian firm, in the U.S. The first JHSV won't be ready for another two years, although they will show up at six month intervals after that. But both the army and the navy are seeing a more urgent need for these ships.
All this began eight years ago, 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 HSV is actually a small ship, 320 feet long and displaces 1900 tons. It can carry up to 800 tons of cargo and has airline style seating for 300 troops, although up to 600 can be carried. 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 Pacific.
There is also a helicopter pad and space for two UH-60 or CH-46 class choppers. The basic crew is only 20, but there are crew quarters for 51 and the galley can feed up to 150. The important aspect of the HAV 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 HSV design is also being studied as the basis for a new class of coastal warships.
The army isn't new to owning its own transports. Back during World War II, the U.S. Army actually had a larger fleet (but only 1,225 seagoing ships), than the U.S. Navy, but one that was almost entirely support vessels. The navy had a larger tonnage of ships, about 12 million tons, compared to about 7 million for the army. Moreover, the navy had 6,228 seagoing ships, about half of them warships. The rest were support ships.
The big change after World War II was the loss of most of the amphibious ships (including most of the 140,000 small amphibious craft the army and navy used), and support ships. Increasingly, the navy used commercial shipping to move a lot of supplies around, and had a lot fewer support ships in general. This was largely because during World War II, the navy had maintained a huge fleet of warships (over a thousand) in the Pacific, almost entirely without ports for replenishing. This was an unprecedented operation, the likes of which will probably never be seen again. The navy also took over most of the army support ships (the two services had been feuding over the size of the army fleet ever since mid 19th century). But the army still has a need for some of its own ships, mainly for operating ports and amphibious beachheads. The army wants the JHSV for moving supplies and troops. The army likes to remind the navy, and the marines, that soldiers carried out more amphibious operations in the last century than the marines have, and are still ready to fight their way across a defended beach.