Sea Rigs

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An oil rig for use at sea

Image Courtesy of Liverpool Daily Post & Echo

As a young news reporter in the 1970s I flew by helicopter to an exploratory gas rig in Morecambe Bay on a facility trip. We were taken on a fascinating tour but what I remember most was how strange we all looked in flight suits and helmets.

This was especially true of Ron and Les Clare – twin brothers who were at that time the Liverpool correspondents of the Daily Telegraph and Daily Express respectively. Oil and gas rigs may not be the most beautiful structures on the seas but they have become familiar sights off our coasts. A 1:100 exhibition model of the Sovereign Explorer semi-submersible oil rig at Merseyside Maritime Museum bristles with amazing detail and demonstrates the supreme practicality of these craft.

In 1981 shipbuilders Cammell Laird of Birkenhead received an order from Dome Petroleum Ltd of Canada to build this drilling unit for offshore oil exploration. At that time it was the most valuable offshore contract obtained from abroad for a British yard, marking the start of a new era for Laird’s. The massive Sovereign Explorer was handed over in June 1983. Standing at 109 metres, she was specially designed to tap the vast resources of oil located beneath the sea bed in the North Sea’s British section.

Sovereign Explorer was a steel catamaran where two huge hollow barges or pontoons supported a three-deck platform on four columns. She was capable of drilling to a depth of 7,600 m and exploring underwater depths of up to 600 m in severe wind and sea conditions. Another 1: 100 exhibition model depicts the self-lifting offshore accommodation platform AV-1 of 1985, also built at Cammell Laird’s, It was built for British Gas for use in the Morecambe Bay Gas Field. This unit had four 88 m legs with a hydraulic jacking system enabling it to operate in tidal waters to a maximum depth of 47.5 m. It had a helicopter landing deck (helideck), storage areas, workshop, cinema and gymnasium. A huge crane could lift up to 150 tonnes over a radius of 50m.

A gangway provided access to adjacent gas or oil rigs. Until 1975 most of Britain’s oil had to be imported and natural gas came in liquid form on tankers from North Africa. Once natural gas and oil were discovered in the North Sea, a number of fields were developed off North East Scotland and further south. Fields were later developed in Liverpool and Morecambe Bays. Before Britain’s resources began to decline, the industry supported more than 300,000 jobs including 4,000 seafarers on various kinds of offshore and support vessels.

A new Maritime Tale by Stephen Guy appears every Saturday in the Liverpool Echo. A paperback – Mersey Maritime Tales (£3.99) – is available from the museum, newsagents and bookshops.