St Vincent Calder, Squadron Commander Marian Diamond as Sue Herrick, Glenn's girlfriend (series 3) Prunella Ransome as Zoe Carter, Holt's girlfriend (series 4) Royal Navy and Royal Australian Navy co-operation The series enjoyed close collaboration between the Royal Navy and the BBC, and—unusually for a TV drama of the 1970s—looked like a documentary. Seven s played the role of HMS Hero and for continuity, all were repainted with the pennant number F42 of , the main warship used for filming. The others were , , , , and . , a of the Royal Australian Navy, was also used as Hero for some scenes filmed in 1976 in Hong Kong and Singapore. This Australian link and Australian broadcasts of Warship influenced the production of the later and similar Australian Broadcasting Corporation series Patrol Boat. The crews of these frigates - and Derwent - were given Hero cap tallies for filming purposes, and their ships were given HMS Hero ships' badges, name plates and lifebuoys. Similarly, their Westland Wasp helicopters from the Fleet Air Arm's 829 Naval Air Squadron were all repainted with the identification HMS Hero, the code 471, and the nickname "The Fighting Forty-Two". Among the Wasps used for the fictional Hero Flight were serial numbers XT419 from HMS Phoebes Flight, XV625, and XV626. (One of these Wasps, XV625 still painted with the 471 code, is preserved at in the Royal Naval Air Engineering and Survival School.) These measures, along with the use by all the frigates of the pennant number F42, had the unintended side effect of confusing Soviet spy ships. Other Royal Navy warships used for the series included the aircraft carrier , the helicopter cruiser , the commando carrier and the submarine . The Royal Marine Commandos took part in the series, as also did the Fleet Air Arm, the Royal Naval Reserve in the shape of the , the Royal Fleet Auxiliary in the shape of and other ships, and the Royal Maritime Auxiliary Service. Fleet Air Arm squadrons embarked on HMS Ark Royal used for filming included the Buccaneer S 2s of 809 Naval Air Squadron and the Phantom FG 1s of 892 Naval Air Squadron. The Westland Wessex HU 5s of 845 Naval Air Squadron embarked on HMS Bulwark also featured in some episodes. The series was also filmed ashore in, among other places, Gibraltar, Malta, Hong Kong, Singapore, north-east of Isfjellet in