دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a mechanism that is fitted into an overshot to grasp and retrieve fish from the borehole. The interior of a grapple is wickered to engage the fish. See basket grapple. spiral grapple.

n: the part of a catching tool (such as overshot or spear) that engages the fish.

a spring like device, resembling a interlocking finger puzzle that allows a round work piece to slide through the ID when in compression, but grips the work piece (or fish) when a tension load is applied. Common in overshot fishing devices.