RE: [Paddlewise] sails on plastic boats

> Dear all

> I have a plastic skerray sea kayak. I'm thinking of mounting a locally
> designed and successful sail on it. It uses a universal joint mounted on
> the deck to which the mast will be attached. To date it has been used only
> on fibreglass boats that I am aware of. I'm concerned about the
> pressure on
> the plastic deck and imagine that some sort of reinforcing will be needed,
> maybe a plate of stainless steel, or simply  a sheet of kayak plastic,
> bolted to the deck. Does anyone have any experience of this, or any
> suggestions?
>
> nick gill
>

Nick

I made a mast step for my plastic P&H Capella last year, to mount a sail
along the lines of the Tasmanian sail design (modified from Laurie
Ford/Grant Hyland/Jeff Jennings sail patterns
:http://www.vision.net.au/~jennings/sail/sail.html) and have so far had no
problems.

My step heavily reinforces the deck. I first layed up a couple of layers of
GRP under the deck about a foot wide, and two and a half feet long, from the
front of the cockpit coaming to about eight inches forward of the step
location (which roughly is over my ankles sat in the cockpit). Once this had
cured it was removed from the inside of the boat and the same length of
~eight inch diameter plastic drain pipe (which had had its top cut off to
form a u-tube) was layed fore and aft on the (inside of cockpit side) glass
sheet. Another couple of layers of glass were applied over the sheet and U
tube and sanded smooth. This assembly formed a rigid knee tube with a wide
flange, and the deck and this assembly were then drilled with 22mm holes to
accept six inches of brass pipe mounted vertically (the step itself). I cut
a thread on the top of the brass step pipe and then glassed this into the
knee tube assembly so that 2mm of the thread would protrude through the
deck. The deck and knee tube assembly was then drilled with eight holes in
two lines of four spaced to be just inside the tube, and two 1cm strips of
brass the same length were similarly drilled as backing strips. All the
holes in the deck were smeared with silicon sealant and the whole assembly
was  bolted under the deck with brass nuts & bolts and the brass strips
inside the knee tube. Finally I cut  a circular piece of ~ 3mm brass plate
and filed one side to fit the shape of the deck over the protruding threaded
2mm of step, cut a threaded hole in it, smeared the underside with silicon
sealant and screwed it onto the protruding end of the step.

The result is very stiff - much stiffer than just bolting a flat plate under
the deck. If I step my sail on land sitting in the boat side on to a stiff
wind, and sheet it in, some flexing of the deck is noticable which was
initially a concern,  but in the water the boat just heels over and I've yet
to detect any movement of the deck.

The bonus is knee tube storage space .... and being constructed from scrap
odds and sods lying around the workshop, cost minimal.

HTH

Cheers

Colin Calder
57º19'N  2º10'W

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