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Replacement of thwart.

Postby fitzwarryne on Wed Dec 21, 2005 2:09 pm

As I sheeted in hard to go to windward in a 20 knot breeze, the thwart on my 266 broke at the traveller location. Obviously it is a high streess area as numerous cracks radiated out from the control sheet hole, and not just because it sometimes has 80 kg sitting on it. What wood should I use in replacing the thwart, is softwood adequate or should I use something stronger but more heavy such as ash?
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Postby swearly on Wed Dec 21, 2005 8:17 pm

I have seen this problem before. Soft timbers seem a little week. The ideal solution is a laminated thawt. If not I would use ash.
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Thwart

Postby Eliza C on Fri Jun 09, 2006 4:36 pm

Hi

Does anybody know the part no. for the little reinforcing pieces that go through the thwart for the bridle?

Thanks

Shane C
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Sabre bridle ferrules

Postby Phillip Johnson on Sat Jun 10, 2006 10:25 am

I use Riley RM166 top and bottom to allow the bridle to be adjusted easily.
Be careful to make the holes in the thwart as small as possible and glue them using a marine epoxy such as West or Bote Cote. For the replacement thwart make sure it is maximum size 50x19. The timber type does not seem to matter providing the thwart is well anchored at the side tanks and the top of the centrboard case. The latter is very important.
The use of silver ash would make the new thwart indestructible.

Phillip Johnson
National Measurer
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New thwart

Postby Slow Hand on Sat Jun 10, 2006 4:08 pm

I recently built a new thwart for 991. I laminated gaboon ply and tasmanian oak. The latter being straight from Bunnings. The effect was great and the satisfaction even greater.
I didn't have sash clamps, but made do with a good number of g-clamps, plus making the initial timbers longer than required and bolting them together at each end. To compensate for not using sash clamps.
The finished job was then planed and sanded smooth before tediously cutting to refit to the slot on each side.
I also agree that the connect to the centrecase is very important. It was this area that had a lot of deterioration in the original, plus the use of holes for the traveller that were much too big.
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Postby fitzwarryne on Sun Jun 11, 2006 5:46 pm

I ended up laminating timber from the remains of the last spruce NS14 mast made. It was well seasoned after 20 years. The result was a ulta light stiff thwart. Following Phillip's advice on the necessity of anchoring the ends and centre is essential, so I spent some time making tight ends glued in place under pressure. I also used the Riley fittings on the traveller running end.

I acquired a few spares from 991 from her previous owner to bring 266 up to standard after 30 years use!
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