The board pivots off a pin under the deck close to the windward side of the lee hull. The faired brace attaches to the board just below waterline and thrusts against the longitudinal beam that supports the cockpit. I have attached a photo.
The photo shows the board almost up in its stowed position. The toe plate clears water level by about 300mm when fully up. The overall length is about 3m.
This board was a later addition to regain pointing ability to at least match pointing ability with the 900 span rudders that got mushed in a grounding. The board improved pointing ability over the big rudders. This arrangement was the simplest to engineer to avoid major modifications. The fact that the pivot is at a top corner makes the mounting of the brace more complicated because the pivot of the brace and the pivot of the board need to be axially aligned.
The board is not far from the centreline of the lee hull so does not generate much weather helm. It would be better to have it on the lee side of the lee hull from a balance perspective but then it would be more difficult to set up the lines for raising and lowering. It would also need a pivot mounted to the lee side of the lee hull.
For a purpose design it would be preferable to pivot the board at the middle of the top edge. But that would require the pivot point to be half the board chord below the deck so the board could be stowed under the deck with toes out of the water. The pivot would align reasonably closely with the bottom of the cockpit so that would be a suitable place to brace it.
Rick
On 28 Mar 2019, at 10:36 am, doha720@yahoo.co.uk [harryproa] <harryproa@yahoogroups.com.au> wrote:Hi rick,
Thanks for info.
Am seeing that an addition of a board could be useful for my old boat Sidecar (el camper) and for a similar new bigger boat if it happens.
So your board is actuallh on ww hull side?
I had a look at all vids on youtube but no sight of it.
Ww hull has a few benefits as you say, loading and also maybe if on a smaller boat it could be swung up by hand from cockpit.
I can't figure what effects balance when having board on lw or ww hull.
When sailing Sidecar i was not overly impressed by windward ability, though i put that down to cheap mast and own skill.
It was good enough for practical purposes, just not too high.
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Posted by: Rick Willoughby <rickwill@bigpond.net.au>
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