Shelter Island Boat Works

Having built the centerboard it was time to build the centerboard trunk. The centerboard is 3/4″ thick (add some for the glass and epoxy coating). The inside of the trunk is 1″ and the slot through the keel is 7/8″. Nice tight fit so the board will not bang around under sail.

When I was building the hull I cut the centerboard slot in the keel and hog to match the previously made centerboard to assure a tight fit.

The sides of the trunk are 1/2″ Mahogany plywood and the end caps are solid mahogany. The two sides were cut to length, matched, leveled and placed into the boat to scribe the curve of the keel.

The sides and the end caps were assembled, glued and screwed and bunged. The insides of the trunk were given two coats of bottom paint before assembly. Then solid mahogany bed logs were scribed to the keel and attached to the trunk. Test fitting required slight planing to create a very tight joint. The whole assembly was then glued and screwed to the keel. Epoxy squeeze out was removed on the inside seam to assure a clean slot for the board.

A cap of solid mahogany was made for the cover with a 1″ wide slot for the raised centerboard.

A hole for the centerboard pivot was drilled through the bed logs and trunk sides to receive a 3/8″ solid bronze rod. The board was placed into the slot, secured to assure proper clearances, and then a hole was drilled through the board. The hole was enlarged to accept a copper pipe lining, well epoxied in place.

Holes for a 3/8″ solid bronze pin were drilled in two positions. One for board all the way up, and one for half raised. A line and grab handle block were attached to the board to stop the board in the fully down position. After varnishing bronze half ovals will be put under the pin on the cover to protect it.