West sole gas line trenched swiftly by post-burial plow

A ''post trenching'' aspect and soil conditions made it necessary for British Petroleum to plow-trench its 43.75-mile (70 km), concrete-coated 24-in. (610 mm) steel pipeline from the West Sole gas field offshore in the North Sea to the BP Easington Terminal. The capability to set a plow over an existing pipeline and to bury it in its prelaid location is an invaluable alternative to pretrenching techniques or to conventional jetting sleds. Design and modifications to equipment, instrumentation, control systems, and support vessels had to be performed in a 6-month period. Computer display CRT monitors onboard the barge helped insure that anchor movements and subsea activities remained a safe distance from another live gas pipeline along the route of the new line. Overall plowing rate average was 1.125 miles per day (1.8 km) or 1.25 m per minute (4.1 ft) on the offshore section.