One of the Sea Gem’s legs collapsed while it was working in the North Sera in December 1965
The Sea Gem was originally a 5,600 steel barge was converted into an oil rig by BP in 1964. The jack up barge was based on 10 steel legs which was able to raise the hull 15 metres (49 ft) over the water’s surface. It had a crew of 34. At one end was a drilling derrick.
When moving the Sea Gem from a site 67km off the lincolnshire coast to anothe rlocation 2 miles away, the barge jacked down to the water surface. During the process, two of the legs broke and the rig capsized.
The radio room sank into the sea without sendin out a distress signal, but the accident was spotted by the freight ship the Baltrover which was able to help rescue the crew