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The SR.N4 (Saunders-Roe Nautical 4)〔(【引用サイトリンク】title= James' Hovercraft Site: SRN4 )〕 hovercraft (also known as the Mountbatten class hovercraft) was a large passenger and vehicle carrying hovercraft built by the British Hovercraft Corporation (BHC). BHC was formed by the merger of Saunders-Roe and Vickers Supermarine in 1966. Work on the SR.N4 began in 1965 and the first trials took place in early 1968. Power was provided by four Rolls-Royce Proteus marine turboshaft engines each driving its own lift fan and pylon-mounted steerable propulsion propeller. The SR.N4 was the largest hovercraft built to that date, designed to carry 254 passengers in two cabins besides a four-lane automobile bay which held up to 30 cars. Cars were driven from a bow ramp just forward of the cockpit / wheelhouse. The first design was long, weighed , was capable of and could cruise at over . The SR.N4s operated services across the English Channel between 1968 and 2000. ==Service== The craft entered commercial service in August 1968, with the ''Princess Margaret'' (of British Rail's Seaspeed) initially operated between Dover and Boulogne but later craft also made the Ramsgate (Pegwell Bay) to Calais route. This craft was featured in the James Bond film ''"Diamonds Are Forever"'' in 1971. The journey time, Dover to Boulogne, was roughly 35 minutes, with six trips a day at peak times. The fastest ever crossing of the English Channel by a commercial car-carrying hovercraft was 22 minutes, recorded by the SR.N4 Mk.III ''Princess Anne'' on 14 September 1995, for the 10:00 a.m. service. In 1972 the first SR.N4s were temporarily withdrawn for conversion to Mk.II specification which would provide for seven further car spaces and 28 more passengers. The first of the enlarged craft, the "Swift", entered service at the beginning of February 1973. The capacity increase was achieved by removing an inner passenger cabin in order to accommodate the extra cars and widening the outer passenger cabin: this was achieved without changing the overall footprint of the craft.〔 New aircraft-style forward-facing seats created an atmosphere of enhanced sophistication, and a redesigned skirt was intended to reduce window spray, enhancing the view out for passengers, and to give a smoother ride in rough seas: contemporary reports nevertheless commented on the "unsprung" nature of the ride.〔 From 1976 two SR.N4s were refitted with new deep skirts and stretched by almost , increasing capacity to 418 passengers and 60 cars at the cost of a weight increase to almost . To maintain speed the engines were upgraded to four Rolls-Royce turboprops fitted with four diameter steerable propellers. The work cost around £5 million for each craft, and they were designated Mark IIIs; the improvements allowed them to operate in seas up to high and with winds. The stretched SR.N4s (Super-4's) became the world's largest hovercraft, holding this title until the Russian Zubr class LCAC hovercrafts' arrival early in the 21st century. The two main commercial operators (Seaspeed and Hoverlloyd) merged in 1981 to form ''Hoverspeed'', which operated six SR.N4 of all marks. In all operations, while the craft were occasionally damaged, there was loss of life only once when on 30 March 1985 the ''Princess Margaret'' was blown onto a breakwater at Dover and four passengers were killed. The last of the craft was withdrawn from service in October 2000 and Hoverspeed itself ceased operations in November 2005. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「SR.N4」の詳細全文を読む スポンサード リンク
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