DONE
Many thanks to the kind members of the UK Gull facebook group for their encouragement and for providing the missing details required to replicate Ingrid's centreboard.
Compost
Some photos of Ingrid's centreboard as received. A large section was missing and what was left was crumbling.
This hole is bored though the trailing edge of the centreboard, it received a locking pin which secured the board in the retracted position for trailering or beaching.
Photos of a UK-based Gull centreboard, detailing the missing section. (Thanks Simon!)
The photo and discussion also explained the mysterious bit of hardware in a box of stuff included with the boat. This is an adjustable friction brake that fits in the slot at the top of the board. It compresses 1” od rubber heater hose enough to span the centreboard case, resisting the board's swing.
Trial fit and hole marking.
As with the pivot bolt reinforcements in the trunk, I decided to make a bearing in the board itself, to protect the pivot area from wear and from water ingress.
Two discs were cut from fibreglass sheet (again, scrap) and sized to fit flush into a 1" hole, which was counterbored into the centreboard. (This is my largest forstner bit. I would have preferred a larger size.) The pivot hole in the board was then drilled to be significantly larger than the bolt diameter.
Trial fit.
The entire thing was filled with very thick, glass fibre laden epoxy putty, clamped and left to cure. Once cured, it was sanded flush and redrilled to the diameter of the pivot bolt. The result is a solid bobbin-shaped glass-filled bushing, bonded into the board.
Old and new.
Shaped to near its final form. This was laid out in pencil, then rough carved with spokeshave, then sanded, starting with 50 grit, through 150 grit. The board will be reinforced at the tip and leading edge, and covered with epoxy saturated fiberglass cloth.
The board is now ready to be covered in fiberglass cloth.
Up Lock Down Stop
I have no idea what its called but the original board ad a dowel at the end of the handle to limit its downward swing, and a hole in the trailing edge to receive a pin, which held the board in the retracted position. I decided to combine the two in the arrangement below, made from two thicknesses of HMWPE turned on the drill press. The step is intended to receive a loop of shock cord to retain the board in the retracted position.
Trial Fitting
The photo below shows the board fully deployed. From below, its leading edge is more or less vertical. I would surmise that the UK boats, whose boards appear to have a shorter handle, have a leading edge that is somewhat angled.
And in the retracted position. This will be secured with a loop of shock cord, exactly how remains to be determined.
I was asked for dimensions to assist with another restoration - so here they are.
Great work..
ReplyDeletethanks!
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