Centerboard Shape and Specs

Submitted by johnrmcl on Thu, 04/24/2008 - 14:20
I am repairing a much munched centerboard and have received a template from FS to help with this. I have visited a website sponsored by Quannapowitt Yacht Club that discusses repair of a FS cenerboard - with pictures. The discussion and pictures present a board that is largely symmetrical fore and aft and presents a conversation with Harry Carpenter indicating the leading and trailing edges have the same profile and shape. The pattern I recieved from FS matches the basic shape of the board that I have (minus large pieces that the previous owner and I have left on various lake and river bottoms) but does not match the shape of the board pictured in the yacht club article. Does the class sanction more than one board? John McLaughlin Ngulule Customflex #1554
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Comments

I find it interesting that I have not one reply to this topic.

Submitted by johnrmcl on Tue, 05/06/2008 - 19:56.
I find it interesting that I have not one reply to this topic. Even the centerboard shown in the official measurement document has a different shape from the template that Flying Scot sent to me to use when redoing my board and an accompanying sketch showing the official lengths and widths has a different shape from the template. The template sent to me has very large radius curves at the termination of the straight foreward and aft edges, while the sketch and measurement specs show a very long straight leading and following edge with very abrupt curves (smaller radius) at the transitions. John McLaughlin Ngulule Customflex #1554

It sounds like you have the information you need, if you have a

Submitted by sawyerspadre on Tue, 05/06/2008 - 21:26.
It sounds like you have the information you need, if you have a template from Harry. I have never heard of more than one board. Phil Phil Scheetz FS 4086

Phil Scheetz

FS 4086

Fleet 163, Nockamixon Sail Club

I'm looking at the same templates, from the builder.

Submitted by ClarkT on Mon, 06/30/2008 - 15:53.
I'm looking at the same templates, from the builder. Interesting that when I fold the template in half and check for fore/aft symmetry, they are off by 1/8" on each side. Last year I saw some boards measured, and the measurer's used a feeler guage to check for symmetry, same sort of thing you would use to transcribe the shape of a crown molding. They take the profile of one side, then flip the guage fwd/aft and compare the difference. Repeat for the opposite side. From what I have seen, the measurers are looking for compliance with the "spirit of the rule", that a NACA foil shaped board is illegal, and within reasonable manufacturing tolerances the board should be symmetrical. The board that was measured from a brand new boat was very similar to the builders template, slightly asymetric fwd/aft, but clearly not an attempt to make it foil shaped. Someone please jump in if I have this wrong.

ClarkT is correct that the "spirit of the rule" is what the clas

Submitted by fssaeditor on Mon, 06/30/2008 - 16:56.
ClarkT is correct that the "spirit of the rule" is what the class is after in older boats: a symmetrical shape. Historically there had been variances in board shapes, particularly among different manufacturers. Also, there was some history of DIY board modifications which changed the symmetry of the foil. The template received from Flying Scot Inc. represents the symmetrical shape which should be used as the model for centerboard restorations; and is the one used in manufacturing new boats today. The intent is that there be one board shape for the class; that represented by the template. Any measurements done for competition, such as the NAC, are done on this basis. If a board's foil shape has been modified, it would have to be corrected before being used in the competition. If a board clearly hasn't been modified, but it doesn't match the template, there's a likely judgment that the board may be used. FSSA Forum editor