Mountbatten class hovercraft
Encyclopedia
Hovercraft
A hovercraft is a craft capable of traveling over surfaces while supported by a cushion of slow moving, high-pressure air which is ejected against the surface below and contained within a "skirt." Although supported by air, a hovercraft is not considered an aircraft.Hovercraft are used throughout...
built by the British Hovercraft Corporation
British Hovercraft Corporation
British Hovercraft Corporation was the corporate entity created when the Saunders Roe division of Westland Aircraft and Vickers Supermarine combined March 1966 with the intention of creating viable commercial hovercraft - .None of the Vickers designs were 'taken forward', the...
(BHC). BHC was formed by the merger of Saunders-Roe
Saunders-Roe
Saunders-Roe Limited was a British aero- and marine-engineering company based at Columbine Works East Cowes, Isle of Wight.-History:The name was adopted in 1929 after Alliot Verdon Roe and John Lord took a controlling interest in the boat-builders S.E. Saunders...
and Vickers Supermarine in 1966. Work on the SR.N4 began in 1965 and the first trials took place in early 1968.
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 40 metres (131 ft) long, weighed 190 long tons (193 t), was capable of 83 knots (163 km/h) and could cruise at over 60 knots (118 km/h).
The SR.N4s operated services across the English Channel
English Channel
The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...
between 1968 and 2000, until the abolition of duty free made their service unprofitable.
Service
The craft entered commercial service in August 1968, with the Princess Margaret (of British RailBritish Rail
British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...
's Seaspeed
Seaspeed
Seaspeed was the joint hovercraft operations of British Rail in association with the French SNCF....
) initially operated between Dover and Boulogne
Boulogne-sur-Mer
-Road:* Metropolitan bus services are operated by the TCRB* Coach services to Calais and Dunkerque* A16 motorway-Rail:* The main railway station is Gare de Boulogne-Ville and located in the south of the city....
but later craft also made the Ramsgate
Ramsgate
Ramsgate is a seaside town in the district of Thanet in east Kent, England. It was one of the great English seaside towns of the 19th century and is a member of the ancient confederation of Cinque Ports. It has a population of around 40,000. Ramsgate's main attraction is its coastline and its main...
(Pegwell Bay
Pegwell Bay
Pegwell Bay is a shallow inlet in the English Channel coast at the estuary of the River Stour between Ramsgate and Sandwich in Kent. Situated in the bay is a large nature reserve, known for its migrating waders and wildfowl, with a complete series of seashore habitats including extensive mudflats...
) to Calais
Calais
Calais is a town in Northern France in the department of Pas-de-Calais, of which it is a sub-prefecture. Although Calais is by far the largest city in Pas-de-Calais, the department's capital is its third-largest city of Arras....
route. 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 to 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-tyle 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 56.1 ft (17.1 m), increasing capacity to 418 passengers and 60 cars at the cost of a weight increase to almost 265 LT (269 t). To maintain speed the engines were upgraded to four 3500 shp Rolls-Royce
Rolls-Royce Limited
Rolls-Royce Limited was a renowned British car and, from 1914 on, aero-engine manufacturing company founded by Charles Stewart Rolls and Henry Royce on 15 March 1906 as the result of a partnership formed in 1904....
turboprop
Turboprop
A turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear.The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller...
s fitted with four 21 ft (6.4 m) diameter steerable propeller
Propeller (aircraft)
Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...
s. 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 11 in 6 in (3.51 m) high and with 57.5 miles per hour (92.5 km/h) winds. The stretched SR.N4s (Super-4's) became the world's largest hovercraft, holding this title until the Russian's Zubr class LCAC
Zubr class LCAC
The Zubr class is a class of air-cushioned landing craft of soviet design. This class of military hovercraft is currently, as of 2008, the world’s largest hovercraft. There are currently nine ships in active service in the world. The Zubr is used by the Russian, Ukrainian, and Greek navies...
hovercraft's arrival early in the 21st century.
The two main commercial operators (Seaspeed
Seaspeed
Seaspeed was the joint hovercraft operations of British Rail in association with the French SNCF....
and Hoverlloyd
Hoverlloyd
Hoverlloyd operated a cross-Channel hovercraft service between Ramsgate, England to Calais, France. It operated four SR.N4 type hovercraft and was a rival to Seaspeed .-Company ownership:...
) merged in 1981 to form Hoverspeed
Hoverspeed
Hoverspeed, formed in 1981 by the merger of Seaspeed and Hoverlloyd, was a ferry company that operated on the English Channel from 1981 until 2005....
, 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
Breakwater (structure)
Breakwaters are structures constructed on coasts as part of coastal defence or to protect an anchorage from the effects of weather and longshore drift.-Purposes of breakwaters:...
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.
Military
The Royal NavyRoyal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
considered a mine sweeping version of the SR.N4, hovercraft being almost invulnerable to mines
Naval mine
A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...
, but it never got further than the concept stage, although an SR.N3 was used by the Inter-Service Hovercraft Unit for trials.
Survivors
The two remaining Mk.III examples of the craft (GH-2006 Princess Margaret and GH-2007 Princess Anne) were bought by Wensley Haydon-BaillieWensley Haydon-Baillie
Wensley Haydon-Baillie, the son of a surgeon from Worksop, Nottinghamshire, was once one of the 50 richest men in the UK after working his way up in the pharmaceutical industry. He owned a collection of Rolls-Royces and an aviation museum housing and restoring many Spitfires. He also owned...
for £500,000 and reside at the Hovercraft Museum
Hovercraft Museum
The Hovercraft Museum, located in Lee-on-the-Solent in Hampshire, England, is dedicated to hovercraft.The museum has a large collection of various designs of hovercraft - numbering over sixty at the last count...
. Haydon-Baillie is the owner of the super yacht Brave Challenger and uses the same Rolls Royce Proteus Marine engines as the SRN4s. The purchase included 7 years worth of spares including engines and so no parts have been removed from the SRN4s for use on Brave Challenger. The SRN4s are currently for sale and Hover Transit Services of Bolton, Ontario, have proposed putting the hovercraft back in operation (following a $10 million USD purchase and refurbishment) on Lake Ontario
Lake Ontario
Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north and southwest by the Canadian province of Ontario, and on the south by the American state of New York. Ontario, Canada's most populous province, was named for the lake. In the Wyandot language, ontarío means...
with service between Rochester, New York
Rochester, New York
Rochester is a city in Monroe County, New York, south of Lake Ontario in the United States. Known as The World's Image Centre, it was also once known as The Flour City, and more recently as The Flower City...
, and Toronto, Ontario.
Production
Built as Mk.I unless specified otherwise.- 01 - GH-2006 Princess Margaret, 1968 originally the prototype converted to Mk.III specification in 1979
- 02 - GH-2004 Swift converted to Mk.II specification for February 1973, broken up in 2004 at the Hovercraft Museum
- 03 - GH-2005 Sure 1968, converted to Mk.II specification in 1972, broken up in 1983 for spares
- 04 - GH-2007 Princess Anne converted to Mk.III specification in 1978
- 05 - GH-2008 Sir Christopher 1972, converted to Mk.II specification in 1974, broken up 1998 for spares
- 06 - GH-2054 The Prince of Wales built as Mk.II, scrapped in 1993 due to electrical fire.
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 tTonneThe tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
- Mark 2: 200 t
- Mark 3: 320 t
- Powerplant: 4 x 3,400 shp Rolls-Royce ProteusBristol Proteus|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9* Hooker, Sir Stanley. Not Much Of An Engineer. Airlife Publishing, 1985. ISBN 1853102857....
Gas turbineGas turbineA gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between....
s (3,800 shp in Mk.III) - Load:
- Powerplant: 4 x 3,400 shp Rolls-Royce Proteus
- Mark 1: 30 cars and 250 passengers
- Mark 2: 36 cars and 278 passengers
- Mark 3: up to 60 cars and 418 passengers (112 tonnes maximum)
Performance
- Max speed: Mark 1 - 65 knots (calm water, zero wind, at gross laden weight)
Mk.II - 70 knots (137.2 km/h) - Normal operating speeds: 40 - 60 knots (117.6 km/h)
- Endurance: 4 hours (maximum power, 2,800 Imperial gallons of fuel)
- Gradient: 1 in 11