Merlin 133/134s (derated from to ) were fitted to all Sea Hornets. Other specialised naval equipment (mainly different radio gear) was fitted and provision was made for three camera ports, one on each side of the rear fuselage and one pointing down. Sea Hornet F.20s also incorporated the modifications of the Hornet F.3, although the internal fuel capacity was 347 Imp gal (1,557 l), slightly reduced from that of the F.1. The modifications added some 550 lb (249 kg) to the weight of the aircraft. Maximum speed was decreased by 11 mph (18 km/h).