Center board banging

Moderator: GreenLake

Center board banging

Postby Solarwinds » Sat Jun 25, 2016 11:34 pm

When I'm running, the centerboard has a tendency to bang in the trunk. Is this something you all experience or do I need to do something to service it?
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Re: Center board banging

Postby GreenLake » Sun Jun 26, 2016 5:39 pm

I had noise from the CB that disappeared when I faired it. But this noise was more like a flutter than a banging.

Atypical for an older DS1, my CB is supported not just on one side, but on both - someone drilled and tapped the CB pivot and ran a bolt into it, from opposite the handle.

If suspended only on one side, as per original design, I can see how flutter might build up to oscillations that result in banging.

Now, one reason the original design works as well as it does is that the CB tends to "wedge" itself into the trunk under load. Some people build up the opening a bit to make that more effective. (Class rules allow the first 4" of the inside of the CB trunk to be built up in this way).

You might take a look at your CB. If it's pretty banged up try fairing it (look in older posts). Test it. Report back.
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Re: Center board banging

Postby kokko » Thu Jun 30, 2016 10:13 am

I had a little slop in my cb that was not corrected by squaring the hole for the cb handle. I bonded two strips of 1/4 x 2" plastic lumber to the inside of the cb trunk, so when the cb was down there as less play side-to-side. These two strips were about 12" long and I bonded them with 4200 using shims between the sides of the cb and the inside edge of the trunk. Once the 4200 cured, the shims were removed. Essentially I narrowed the width of the cb trunk
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Re: Center board banging

Postby Lil Maggie » Sat Jul 09, 2016 9:01 pm

When I put in the foil (with thicker trunk section) the banging went away...
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Re: Center board banging

Postby druidae1492 » Mon May 15, 2017 12:40 am

My CB has a 1/4" thick X 12" square piece of rubber on each side. It was tricky squeaking the CB into place and having all three holes line up, but I got it. And the CB stays were I put it and does not bang inside its trunk. :)
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