centerboard handle work/ insight needed

[dsheer]

Carlos,

Good Luck. Let me know how it works. Just a cautionary note: The centerboard is like a lever. In the original setup, the fulcrum is the bottom of the hull, and the force on the fulcrum is proportional to the ratio of the length of the board below the fulcrum to the length above the fulcrum - all else being equal. if you move the fulcrum up (i.e. if the board is no longer hitting the bottom of the hull, and is rather resting against your shim, the force on the fulcrum is much increased, and this might not be good. Your board may or may not still wobble enough (or bend enough) to hit the bottom of the hull which would eliminate the problem. My shims still let the board hit the bottom of the hull, so no problem, but it still wobbles, and I don't like it. What it doesn't do anymore is to move so far to port that the brass center plate with the square hole comes off the square portion of the handle shaft.

Shims plus a narrowing of the slot at the bottom should actually reduce the wobble, and allow the shims to be tighter without becoming the fulcrum. But note the minimum standard for the width of the slot in the racing rules. My shims were a temporary fix 'till I could work out the geometry and so I could get the boat in the water and not worry. My previous post was way too long already, so I didn't share this extra detail. It may all be BS anyway, but it makes sense to me.

Dan

[calden]

Dan:

Good point. I hadn't thought of that. However I would think that reducing the wobble, even if it raises the fulcrum as you point out, would help reduce the likelihood of stress damage to the pivot mechanism.

In any case there is still play in the washers I put in, and the face plate screwed on all the way so I know the square pivot pin is fully seated. I'm going out today - I'll think about all this as I tootle along.

Carlos

[KaiB]

Dan makes a very good point here. Very interesting - to inquring minds with way too much idle time anyway.

As the fulcrum moves up, it appears to me that the righting moment would also move up, and for any given heeling force, less righting would occur.

Maybe I just need more coffee.

Off topic - I would like to replace my halyards with 1/4" Sta Set...any complaints or suggestions. As I understand it, any rope with significantly less stretch is also that much harder to splice (StaSet X, for example).

Kai

[Peter McMinn]

Kai, I replaced my internal "wire rope" main halyard last year as it broke at a chaffing point (later discoverd) in the mast. Basically, due to the rediculous expense of buying same, I went with non-stretch 3/16" line. I agree on your point with the splicing--not a splicer myself, but know the technique. I just tied a shackle on the end with a bowline and called it good. This has worked well for over a year, and I don't anticipate many hitches.

[Roger]

I upgraded to Stay tec on my jib this year and put in my own eye splice. It was a bit more difficult, but not impossible.

The important item I want to mention here is the diameter of the line. I would highly recommend at least 5/16" and for sheets go to 3/8" for any line your are going to manage by hand. I had 1/4" Spinnaker and Drifter sheets, and they were really hard on the hands due to their small size. Having said that, make sure your blocks and cleats can handle the larger line.

[calden]

I upgraded my main sheet to 3/8 and my assessment is that it feels a bit cumbersome at times - just too much rope. I've still got the original jib sheet, which is 5/16, and when I handle it, it feels fine - I don't notice it. I may go back to 5/16 for the main. Still deciding.


Carlos