دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a system for monitoring the position of a floating offshore drilling rig in relation to the subsea wellhead. A taut steel line is stretched from the rig to the ocean floor. An inclinometer measures the slope of the line at the rig, and, because the line is assumed to have been straight when stretched from the rig to the ocean floor, any angle in the line indicates that the rig has moved. The systems weakness is that the tautline can be distorted by currents and thus give inaccurate readings. Compare acoustic position reference, position-reference system.