A gas platform worker was airlifted to hospital with a crushed leg.
The accident happened off the Norfolk coast, about 60 miles from Spurn Point.
Members of HM Coastguard were called to the emergency at 7.10am on October 17.
A Coastguard spokesman said the injured man had a crushed leg and was flown to the Hull Royal Infirmary.
The oil and gas platform worker had been on the Kronborg supply vessel when the accident happened.
It is understood the man was transferring between the Kronborg and the unmanned gas platform operated by Shell.
Coastguard rescue workers were joined by the Yorkshire Ambulance Service.
The Health and Safety Executive is investigating the incident.
Officers investigated the Kronborg at Great Yarmouth after the accident.
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