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.

The front body (2) has holes (3, 4) for receiving the ends of the wishbone boom, and an arched surface (7) intended to be applied against the mast. An arched clamping piece (9) is provided at each end with a metal rod (10, 11), each of which is intended to pass through a hole in the front body (2). The free end of these rods is threaded (13, 16) and projects beyond the body (2). The rod (10) is straight and the rod (11) is bent. A nut (17) is intended to cooperate with the thread (16) on the bent rod so as to ensure that the mast is held, with play, between the two arched parts (7, 9), while another nut (14), cooperating with the thread (13) on the rectilinear rod, enables the windsurfer to lock the device on the mast after having slid it to the height which suits him. This device can be fitted to the mast, with play, before the sailboard is put in the water and enables the height on the mast to be adjusted while sailing.

An improved windsurfer apparatus includes a boom-mast connector having a collar portion which has a concave inner surface for receiving the mast of the windsurfer, an arch portion which is adapted for grasping by an operator, and a pair of projections having boom receiving sockets defined therein. The connector is of unitary construction, which makes it simple to use and inexpensive to manufacture. The inner surface of the collar portion is shaped so as to contact a mast at two separate contact areas, in a wedge-type fashion. The inner surface is further shaped so as to include upper and lower outwardly tapered contact surfaces, which permit limited pivotal movement between the connector and the mast, and facilitate a better grip between those two elements.