 A single water-cooled Rolls-Royce Hawk engine was mounted on bearers above the level of the rear of the car, and drove a diameter four-bladed propeller in pusher configuration.The SSZ design was judged superior to the SSP, which had been developed at RNAS Kingsnorth at the same time, and so the SSP was cancelled.The SSZ's patrolled extensively from late 1917 to late 1918.