In Britain the Royal Air Force is transferring 25 of its AW101 Merlin battlefield transport helicopters to the Royal Navy for use by the Royal Marine Commandos. These are 15 ton medium aircraft that can carry five tons of cargo or up to twenty passengers. Top speed is 300 kilometers an hour and endurance is about four hours. The AW101s are being navalized, which means folding rotors (to fit on carriers), different communications and some anti-corrosion measures. These changes will cost of about $20 million each. Six are being delivered in 2016 but it will take until 2022 to complete all of them.
The AW101s, although used, are a big improvement over the 1960s vintage Sea Kings they replace. The Sea King has a range of about a thousand kilometers and a top speed of 210 kilometers an hour. Most Sea King were used for anti-submarine warfare and search and rescue. Some 1,500 Sea Kings were built (about ten percent were the civilian S-61 version), and less than a hundred are still in use. Such long service lives are increasingly common because of improved aircraft maintenance techniques. Some of the first Sea Kings built survived for over three decades. And many of the U.S. Navy Sea Kings will continue to serve with the U.S. Marines, where even the U.S. president still travels aboard them.