Starboard Centerboard Repair

We purchased our newest Shearwater without a survey and without inspecting the bottom, confident that we could repair any damage we might find when she was hauled for painting.  Not surprisingly, the aft corner of the starboard centerboard just wasn't there.

Centerboards are designed to automatically pop up when you hit something going forward.  In reverse, if you hit something with the board down, the board snaps.  Kind of a back handed feature to encourage you to lift the boards when backing.

The repair above (this is and after picture) was accomplished by brushing a 50% mixture of epoxy and acetone into the board - it was split upwards about a foot - and clamping it until it was hardened and sound.  We determined the soundness by tapping it with a large stone and listening for hollow spaces.

Once sound, we applied 5 layers, alternating glass cloth and matting, to build the board to its original shape.  The final shaping was accomplished with an angle grinder. 

We tried not to make the repair stronger than new - because if we back over an obstruction, something will break again.

A critical factor in the repair it this a boat bottom, not a table top.  We could have polished it to a table top finish by applying a polyester paste and sanding it with successively finer grits.  This is how we filled the 5 or so above deck holes that held non-working speakers, inspection plates, and just plane holes leftover from abandoned projects.  Below the waterline, epoxy is best and a rough finish is best for anything except racing.  When painted (we used three coats on the repair, two coat on the boat, and two on the waterline - a total of 6 quarts), the repaired board is indistinguishable from new under all circumstances except racing with a polished bottom - something this boat will never see under our hand.

Cost:  About $10 worth of materials we had on hand.