Dave,
You may want to coat the threads of the 3 bolts (the ones that clamp the centerboard handle between triangle plate and centerboard trunk) with an automotive silicone gasket sealer to stop any leakage past the threads. And/or go to the hardware store and get some soft rubber washers and put them around these bolts between the centerboard trunk and triangular plate. Get enough so that when the bolts are tightened down the washers are compressed enough to form a seal.
steve parsons (saabdrver-at-aol.com)