Three yachtsmen whose craft ran aground in driving rain and gale force onshore winds when their GPS failed were winched to safety by a rescue helicopter. They had no charts on board and had to make a rough guess as to their position.

The 25ft yacht, Nelly, was stranded off Bradwell, Essex in bad weather on Saturday. The crew were rescued by the RAF after lifeboats were unable to reach the yacht, a coastguard spokesman said.

A spokeswoman for the Maritime and Coastguard Agency said later: “Due to the severe weather conditions and breaking surf battering the yacht, the three occupants were winched from the vessel and taken ashore.”

Thames Coastguard watch manager Mark Baker added: “This incident highlights the risk of relying solely on a single GPS navigation unit. “A vessel’s position and track should be regularly plotted on a chart and a backup navigation system employed during an offshore passage.”