A man had to be taken to hospital after falling from a yacht near Burnham Yacht Harbour.
The man, who fell after being hit by the boom just before 5pm yesterday, was quickly recovered by the vessel but sustained a back injury.
South Woodham Ferrers Coastguard assisted and ensured the safety of all personnel as the casulty was transferred to an air ambulance to be taken to hospital.
An East of England Ambulance Service spokesman said: "We were called at 5.45pm and dispatched a rapid response car, ambulance, hazardous area response team, paramedic officer and the Herts Air Ambulance.
"We treated a man in his 50s who suffered back and chest injuries.
"His injuries were thought to be serious but not life threatening and he was airlifted to the Royal London Hospital."