Okay, I've actually started back to work on my own boat after too many months. The big project
, at the moment, is replacing the aged and waterlogged centerboard
. I'm doing this now because I'll need it this summer when I haul out
, and I don't want to be rushed in the production. I'll be taking pics of the process, should anyone be interested. The Searunner
centerboards were all built of solid laminated plywood
. Despite adding apitong strips at the leading edge, and lots of glass tape with graphite powder epoxy
, I have managed to bash it enough times to allow water
to enter into the plys. This makes it swell, crack the glass at the feather edges of the trailing part, and make the board hard to raise and lower.
The new design, by my friend and amazing multihull
colleague, Bob Dixon, uses clear redwood, vertical grain planks in the axis of the axle pin. The entire leading edge is laminated redwood planks. The entire aft section, over half the width, is laminated 4# polyurethane
foam. Ten layers of 12" wide graphite unidirectional cloth, vertically aligned will be layed atop the redwood axis core
. Graphite bidirectional cloth will then be laid atop the faired structure. Then, Kevlar/graphite tape will reinforce the impact zones. All sealer coats will be graphite powder in epoxy
resin. I used the graphite as my external coat for all below waterline surfaces when I built the boat, and I love what it does for dragging the boat onto shore when the opportunity arises. Total thickness of the centerboard
will remain under 4", as the original.
I've purchased the redwood, ordered the glass materials from FiberLay in San Diego
, and will be using WEST System epoxy. Construction begins shortly, and I'll be taking photos of the process if anyone wants to see how it works out. When completed, the board should be easily half the weight of the unwaterlogged original, even fairer, with some design changes on the upper bearing surfaces to spread loads to the centerboard trunk more evenly. I've even changed the locking cord and "fused" position latch. Now, if only I can figure out how to close up the "slot" of the trunk to reduce cavitation, I'd really be jazzed. I will also be adding a cavitation plate and end foil to the rudder
when I haul out
. Should help when I get to twenty knots and begin to feel the "spongey water".