DaySailer.org Forum

On 568, I have a custom centerboard that was especially made to fit the trunk snugly enough to eliminate all side-to-side movement. As the spruce foil was was glassed and gelcoated, it became a snug fit indeed. It fits so well that it often becomes lodged in the trunk, which has resulted in my breaking one handle and bending the replacement to a point where the board now cannot be lowered completely. :oops:

I have taken the CB out , sanded down to the glass, and reinstalled, but it still get's stuck. I've come to the conclusion that I need to fair off the glass, sand the board thinner and reglass. I know it's crucial to duplicate angles precisely, and to use some sort of template.

In a previous discussion on fairing the CB ("Boat Pox!"), Michael Shriebman, aka, Captainsesick, mentions downloading "scaled templates for an 00XX NACA airfoil, [transferring] them to cardboard forms and [building] the centerboard to this model."

Can the good captain--or anyone--elaborate on said templates and where to find them?

John,
Both my brothers are egineers, so I understand you a little. Not sure what you mean by "chords to help near the tip", but I don't plan on modifying anything at the tip of the board, as the taper begins aprox. 2/3 down from the pivot. The section of the board I need to fair is above this point, eg, the upper 2/3 of the foil. Your plan with the template, once the correct one is found, is also what I had in mind. I guess I could apply the same method laterally, too (from leading to trailing edges).

If anyone has used a template to build / modify their board, I would be interested in a copy.

Peter:

I don't know if my observations will help at all. Probably not, because what I've done is far less than what you've done in terms of modifications...

My original centerboard was very sloppy in the slot (no, this isn't spam for a Paris Hilton video...) and I installed a couple of 1/4" thick 12" diameter UHMW-material disks, centered around the pivot hole. What I found, at least on my DSI, was that the centerboard slot tapered as it got deeper upwards. So my first attempt at a spacing disk was based on measuring the width of the slot at the hull - but I found that as the centerboard was pulled up into the slot it got tighter, so I had to thin the spacers a bit.

I'm wondering if some of your problem might be this - that you might only need to shave off the bit that sits in the up-end of the slot.

Carlos

John,
I'm hollerin'. But please don't go to any great effort because I'm only interested in finding out if the templates synch with the shaping of my board. Imagining a sort of reduced version of what I have, claro? I can also do what Caldon suggests above--"shave" off a measure of the thickest part of the board. But, again my concern is making very certain that the shape of one side mirrors the other without having been thinned too much.

More suggestions before I begin? Still have some house projects to take on while I plan this, so chime in! Want to be done by sail-time in April.

Here's a link to some drawings I made for a centerboard I built a while ago. They might be of some value.

This will be as helpful as it is elegant. It's also an excellent addition to the site.

Thanks, Bob.