Hi George, I too have a Forespar Tiller Extension and the lock box in the side wall of the cockpit. I thought it would be ideal for holding course when single handing: which it does very nicely..........and for holding the tiller in a fixed position when at the marina dock. This latter use was a total failure. The wash of outboard powered water ski boats; and PWC put such a strain on the rudder / tiller that it split the tiller allowing the screws holding the small Forespar fitting in the tiller to fall out - and the Forespar Tiller Extension was just hanging in the breeze the next time I got to the boat. Apparently waves roll the boat so severely that something has to give in the rigid Forespar / tiller / rudder system, and the weakest link was the Forespar tiller fitting itself - held in placed with two small 1/2 inch screws...... So, back to the drawing board. Now I just use the Forespar Tiller Extension as an autopilot when raising or lowering sail, or to go below to get a sweater or a beer. At the dock, I now fasten the tiller with bungee cords. They can move; but they keep the tiller / rudder from moving too much. Connie M15 #400 LEPPO