Mountbatten class hovercraft
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Mark 3 SR-N4 Hovercraft arriving in Dover on its last commercial flight - 1 October 2000 |
The
Mountbatten class hovercraft or
SR-N4 was built by the
British Hovercraft Corporation (BHC). BHC had been formed by the merger of
Saunders-Roe and
Vickers Supermarine in
1966. Work on the SR-N4 had begun in 1965 and the first trials had took place in early
1968.
The SR-N4 was the largest hovercraft built to that date, designed to carry 254 passengers and 30 cars. The first design was 40 m long, weighed 190 tons and was capable of 83
knots and could cruise at over 60 knots.
The craft entered commercial service in August
1968, with the
Princess Margaret initially operated between
Dover and
Boulogne but later craft also made the
Ramsgate (Pegwell Bay) to
Calais route. The journey time, Dover to Boulogne, was roughly 35 minutes, with six trips a day at peak times. The fastest crossing was made in
1995 at just 22 minutes.
In
1972 the first SR-N4s were converted to Mark 2 specification to allow for seven further car spaces and 28 more passengers. From
1976 two SR-N4s were refitted with new deep skirts and stretched by almost 17 m, increasing capacity to 418 passengers and 60 cars at the cost of a weight increase to almost 265 tons. To maintain speed the engines were upgraded to four 3,500 shp
Rolls-Royce gas turbines fitted with enormous 21 feet diameter
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 3.5 m high and with 50 knot winds.
The two main commercial operators 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
March 30,
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 The last of the craft was withdrawn from service in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 ceased operations in November, 2005.
Interestingly the Royal Navy considered a
mine sweeping version of the SRN-4, hovercraft being almost invulnerable to
mines, but it never got further than the concept stage, although an
SRN-3 was used by the
Inter-Service Hovercraft Unit for trials.
Currently still the world's largest hovercraft. There are two remaining Mk3 examples at the
Hovercraft Museum.
Built as Mark 1 unless specified otherwise.
*01 -
Princess Margaret, 1968 originally the prototype converted to Mk3 specification in 1979
*02 -
Swift converted to Mk2 specification
*03 - GH-2005
Sure 1968, converted to Mk2 specification in 1972, broken up in 1983 for spares
*04 -
Princess Anne converted to Mk3 specification in 1978
*05 - GH-2008
Sir Christopher 1972, converted to Mk2 specification in 1974, broken up 1998 for spares
*06 -
The Prince of Wales built as Mark 2
Dimensions
*Length: :Mark 1 and 2: 39.68 m :Mark 3: 56.38 m
*Beam: 23.77 m
*Height: 11.48 m (on landing pads)
*Gross Weight :Mark 1: 165
t :Mark 2: 200 t
:Mark 3: 320 t
*Powerplant: 4 x 3,400
shp Rolls-Royce Proteus Gas turbines (3,800 shp in Mark 3)
*Load: :Mark 1:30 cars and 250 passengers:Mark 2: 36 cars and 278 passengers :Mark 3: up to 60 cars and 418 passengers (112 t maximum)
Performance
*Max speed: Mark 1 - 65 knots (calm water, zero wind, at gross laden weight)
Mark 2 - 70 knots
*Normal operating speeds: 40 - 60 knots
*Endurance: 4 hours (maximum power, 2,800 Imperial gallons of fuel)
*Gradient: 1 in 11
*
N500 Naviplane*
SR-N4 Hovershow 05 Pictures*
Hovercraft Museum on the Mark 1*
Hovercraft Museum on the Mark 2*
Hovercraft Museum on the Mark 3
