My 1977 DSII has a vibration in the centerboard at certain low speeds. I have repaced the bushing with a new delrin one. I machined it to fit tight in the board and snug on the bolt. Did not want to over tighten the bolt and crack the CB truck. Not sure what to do next, any suggestions? The new bushing is only as wide as the board, should it be wider to fit snug inside the CB truck inside dimension?
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Bushing needs to be longer than Cb is thick
The bushing needs to be about 1/8" longer than the CB is thick, the bushing is actually supposed to be what the CB pivots on, not the bolt. The bushing is longer so that when you tighten the bolt to compress the rubber gaskets (to prevent leaking) you are clamping the bushing in place,not squeezing the CB and thus preventing it from pivoting. Is your CB vibrating when sailing downwind (running)? or when sailing upwind (beating), if it vibrates when sailing downwind you can retract it almost (but not quite!!) all the way (I bring it up until the block on the lift cable gets about 6" or so aft of the mast.) If the vibration is when sailing upwind.....well, that could mean you need to fair the board to make it smoother, but be careful because the fiberglass shell of the CB is thin in places and the CB trunk is not much wider than the CB is thick. The Day Sailer II centerboard is not completely solid, there are often voids that are hollow. There is no ballast in the CB allowed by class rules.
The bushing needs to be about 1/8" longer than the CB is thick, the bushing is actually supposed to be what the CB pivots on, not the bolt. The bushing is longer so that when you tighten the bolt to compress the rubber gaskets (to prevent leaking) you are clamping the bushing in place,not squeezing the CB and thus preventing it from pivoting. Is your CB vibrating when sailing downwind (running)? or when sailing upwind (beating), if it vibrates when sailing downwind you can retract it almost (but not quite!!) all the way (I bring it up until the block on the lift cable gets about 6" or so aft of the mast.) If the vibration is when sailing upwind.....well, that could mean you need to fair the board to make it smoother, but be careful because the fiberglass shell of the CB is thin in places and the CB trunk is not much wider than the CB is thick. The Day Sailer II centerboard is not completely solid, there are often voids that are hollow. There is no ballast in the CB allowed by class rules.
Thanks for the help
Thanks Sunbird, When I dropped the CB the first time I found that the hole in the CB was very wobbled out and that the previous owner had made a failed attempt at replacing the bushing with a piece of PCV pipe and epoxy. I made an assumption that the CB pivoted on the bolt and not the CB. I'll start over with a new bushing. It vibrates on any tack, the boat speed seems to be the driving factor in the vibration. First CB boat I've had, liking the old fixed fin keel boats I previoulsy owned better.
Thanks Sunbird, When I dropped the CB the first time I found that the hole in the CB was very wobbled out and that the previous owner had made a failed attempt at replacing the bushing with a piece of PCV pipe and epoxy. I made an assumption that the CB pivoted on the bolt and not the CB. I'll start over with a new bushing. It vibrates on any tack, the boat speed seems to be the driving factor in the vibration. First CB boat I've had, liking the old fixed fin keel boats I previoulsy owned better.
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