 It was a military version of the SR.N2

Propulsion and lift was provided by four rear-mounted Bristol-Siddeley Gnome gas turbine engines that allowed the SR.N3 to cruise at 70 knots.The British IHTU (Interservice Hovercraft Trials Unit), based at Browndown, Stokes Bay, tested the SR.N3 in a wide variety of conditions, including ice.On 16 September 1964 an SR.N3 operated satisfactorily in a full gale and six foot seas.