Abstract: A mechanism for controlling the extension of a boat anchor line from a boat, to thus anchor a boat in waters of different depths, or to let the boat drift downstream different distances from the submerged anchor. The mechanism includes a line-guidance pulley and a line-gripper device having a spring means for biasing the device to a condition wherein the line is held motionless against travel into or out of the boat. A c-clamp is used to detachably mount the mechanism on the side wall of a small boat.