Although the U.S. Navy carrier fleet has shrunk to ten CVN type 100,000 ton carriers, this is being made up somewhat by the construction of ten 41,000 ton LHD/LHA helicopter carriers that are capable of carrying up to twenty F-35B vertical take-off fighters. The design of these mini-carriers began with the eight Wasp class LHDs. The last of these amphibious assault ships (Makin Island, LHD-8) entered service in 2009 and was followed by two more that had some drastic modifications that led them to being designated LHAs because they were a bit larger (45,000 tons) and did not have the internal dock for landing craft. The additional space was devoted to more fuel, weapons storage and aircraft maintenance. The first of these ships (LHA-6) entered service in 2014 and another is being built. The navy would like to have six of these LHAs but that depends on money being available.
The last of the Wasp class was notable for a number of technical innovations, which it does not share with other ships in the class. Built in Mississippi (and delayed by damage from hurricane Katrina) the Makin Island undertook a two month voyage around the southern tip of South America to its home port in California. This was its first long voyage and the navy found that the gas turbine engines saved some $2 million dollars in fuel costs, versus the steam engines in the other Wasp class ships.
The 41,000 ton Makin Island looks like an aircraft carrier, and it had 21 transport helicopters, six anti-submarine helicopters and five AV-8B vertical takeoff jet fighter-bombers (to be replaced by F-35Bs) on board. Weapons include two RAM missile launchers and two 20mm Phalanx autocannon for defense against anti-ship missiles. There are three 12.7mm and two 25mm machine-guns for protection against small boats (terrorists). The most potent weapon carried consists of 1,400 marines. The marines are landed by helicopter, while three LCAC hovercraft land vehicles. The ship is operated by 1,100 sailors. Top speed is 37 kilometers an hour and range is 17,600 kilometers.
In addition to the unique (for amphibious ships) gas turbine engine, all the auxiliaries are electric, which requires fewer sailors to operate and maintain. There is an improved fire suppression system and the most advanced command and control systems available. The combination of the gas turbine engines and an Auxiliary Propulsion System are expected to result in fuel savings of over $250 million over the life of the ship.
The first LHA began construction in 2009 as the last Wasp entered service and lacked the water level well deck for landing craft. This made it a helicopter landing platform ship, like the 1960s vintage Iwo Jima-class. The first American LPA was called LPH. The Iwo Jima class were 18,000 ton ships that entered service in 1961, and carried two-thousand troops and twenty-five helicopters. The U.S. retired its last LPHs in the 1990s and U.S. Marine Corps has long sought to get them back.
What made this later-day LPH into an LHA was more smart bombs and more powerful vertical takeoff jets (the F-35B). Thus an LHA carrying 12-20 F-35Bs could provide more air support for troops ashore than all the attack aircraft on a pre-smart bombs CVN.
So, why not just build more baseline Wasp-class ships, which only cost about $800 million each? That is about a third of the cost - and it leads to the natural question of whether the Navy would be better off with three baseline Wasp-class LHDs or even sticking with the Makin Island variant - which only costs about 63 percent what LHA-6 will cost (meaning three LHDs like the Makin Island can be built for the price of one LHA-6).
The answer is that the air groups of the Marine Expeditionary Units are undergoing a major change - and the ships that carry them need to evolve to properly support them. At the present time, the amphibious ships tend to carry 12 CH-46 troop transport helicopters, 4 AH-1 attack helicopters, 2-4 UH-1 helicopters, 4 CH-53E heavy-lift choppers, and 6-8 multi-role VSTOL aircraft. This is in the process of changing to 12 V-22s, 8 AH-1s, 10 F-35Bs, 4 CH-53Ks, and 4 Navy CH-60 helicopters. In both cases, actual air combat elements (the term for the reinforced squadron deployed on these vessels) may vary depending on the mission. The LHA-6 is being built with these new aircraft, tilt-rotors, and helicopters in mind.
But the lower price of the LHA compared to a CVN is a concept that is being put to the test as the marines get to see if they can get the same level of air support from a smaller carrier.