SR.N 6 hovercraft

SR.N6 of Hovertravel on the Solent, 1982
Class overview
Name:	SR.N6 Winchester class
Builders:	British Hovercraft Corporation
Preceded by:	SR.N5
General characteristics
Type:	hovercraft
Displacement:	10.9 tons
Length:	17.78 m (58 ft 4 in)
Beam:	7.97 m (26 ft 2 in)
Height:	6.32 m (20 ft 9 in) on cushion
Propulsion:	1 Rolls-Royce Gnome turbine engines 1,050 hp (780 kW) for lift and propulsion driving single four-bladed variable-pitch propeller
Speed:	50 kn (93 km/h)
Range:	170 miles at 30 knots
Capacity:	58 seated passengers
Crew:	3

The Saunders-Roe (later British Hovercraft Corporation) SR.N6 hovercraft (also known as the Winchester class) was essentially a larger version of the earlier SR.N5 series. It incorporated several features that resulted in the type becoming the one of most produced and commercially successful hovercraft designs in the world.

While the SR.N2 and SR.N5s operated in commercial service as trials craft, the SR.N6 has the distinction of being the first production hovercraft to enter commercial service. In comparison to the SR.N5, the SR.N6 was stretched in length, providing more than double the seating capacity. Some models of the craft were stretched further, enabling an even greater capacity.

Experience gained in the development of the SR.N6 has been attributed as heavily contributing towards the design and production of the largest civil hovercraft to be ever produced, the SR.N4. Several major design features of the SR.N6 appeared on both the SR.N4 and further hovercraft designs by Saunders-Roe and its successor, the British Hovercraft Corporation.

In late 1964, Saunders-Roe commenced design work on multiple hovercraft designs; in addition to the relatively huge SR.N4 and studies into a prospective 2,000 ton freighter, there was also interest in developing its existing smaller hovercraft range. In particular, the firm had observed customer demand for a model of the SR.N5 that would be capable of carrying a much greater payload; there was a view that the existing craft was uneconomic for what payload it could carry and that an expanded, or 'stretched', model would be able to rectify this. According to Saunders-Roe's own projections, an increase of the craft's payload by 110 per cent would only reduce performance by 10 per cent as the increased payload was in part offset by the expanded cushion area, which meant that cushion pressure would not need to be substantially increased instead.

The first craft to be lengthened in this manner, in effect becoming the first SR.N6, was the ninth SR.N5 to have been produced. Following three months of work to adapt the craft to the new configuration, this first prototype was launched for the first time on 9 March 1965. Portions of the SR.N6's development were performed in conjunction with Hovertravel, a newly-formed operating company located near Sauders-Roe's East Cowes facility. In June 1965, following an initial series of trials, the SR.N6 prototype was delivered to operated by Scandinavian Hovercraft Promotions of Oslo, Norway under the name 'Scanhover'; it was followed by a second craft later that same month.