Abstract: The apparatus comprises two fixtures and a length of line. A primary fixture fits against the mast and interconnects the two spars of the wishbone boom. The second fixture turns relative to the first fixture. The line is attached at one end to the second fixture, threaded through both fixtures and around the mast in a way which attaches the first fixture to the mast and enables increasing the tension in the line to effect a firm attachment. The tension is increased by turning the second fixture, twisting portions of the line to increase the tension and then locking the second fixture to the first to maintain the tension. The twisting of the line provides the user with a mechanical advantage in tightening the line. The locking is done with a pin mounted in the second fixture engaging holes in the first.