Abbas assist with the evacuation of western nationals during the Iranian revolution. While awaiting a decision as to their future employment, the ships of the squadron were engaged in investigations of the many shoals in the centre of the Persian Gulf. The ship visited Muscat and then the decision was made to withdraw the squadron, so passage was set for the UK, with visits to Haifa, Catania and Gibraltar, before arriving in Portsmouth on 19 April. She sailed on 9 May for shoal investigations in Scottish waters and spent July and August in Southampton for docking and repairs at Vosper. The autumn of 1979 was spent off the west coast of Scotland, starting a detailed survey of the Western Approaches to the North Channel, an area where a large number of U-boats were sunk in 1946 after their surrender. Three years in the life of a Royal Navy survey ship 1980–1983 Service 1980–1981 HMS Hydra was employed on surveys off the west coast of Scotland in 1980 and 1981. To West Africa and surveys in the Caribbean 1981–1982 Newly fitted with a leased Sercel Syledis positioning system for evaluation, she sailed on 7 September 1981 to conduct surveys in the Caribbean Sea (see ), surveying the Josephine Bank and the Ampere Bank on 11 and 13 September, as well as investigating "vigia 4", "vigia 7" and "vigia 23". With a maximum speed of using all three engines, when the starboard engine was lost on 21 September, the ship was limited to for the rest of the deployment. She arrived Dakar, Senegal for a visit from 24 to 28 September 1981. On leaving Dakar, the ship was directed to Banjul , on 29 September in order to locate a ditched Senegalese Puma helicopter, which had crashed into the river while landing Senegalese troops during the attempted coup d'état, on 1 August 1981, in the Gambia. Using copies of a recent survey, by sister ship flown to Dakar from the United Kingdom Hydrographic Office, in Taunton, HMS Hydras two surveying motor boats began sounding and sonar sweeping and located the ditched machine, the local port authority marking the helicopter's position with a float. She sailed the next day. She arrived in Lagos, Nigeria, on 5 October 1981, in company with the destroyer (see ), which she had met, by chance, in fog outside the entrance to the port. She sailed from Lagos