Centerboard rocking side-to-side

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Centerboard rocking side-to-side

Postby VTDS2 » Sun Sep 05, 2021 8:27 am

Has anyone else experienced their centerboard rocking port and starboard? This was especially noticeable when our wind died yesterday and we were bobbing in the water. The centerboard was rocking back and forth and making a thumping noise. I confirmed the rocking by swimming out and holding the starboard side of the boat and touching the centerboard with my feet - once the pressure was on from my feet the rocking and thumping stopped.

Thoughts?
If this needs to be fixed, any thoughts on how to start?
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Re: Centerboard rocking side-to-side

Postby jalmeida51 » Sun Sep 05, 2021 2:15 pm

Just sold my Daysailer1 and in rather calm waters the c/b did bang side to side. I think it's just the nature of the beast. You could put shims in the c/b trunk if it really bothers you. Had my boat for over 3 1/2 years and the banging never caused any damage. Before that boat I had a Rhodes19 and that c/b did the same thing. I had that boat over 10 years and saw no damage. I guess in a perfect world no c/b should bang.

This is just my opinion some builders of these boats had no quality control and were in a rush to get them out of the shop. Not much profit building small boats so many cut corners.

John
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Re: Centerboard rocking side-to-side

Postby GreenLake » Sun Sep 05, 2021 6:48 pm

We forget that the level of quality control increased dramatically for most products in the decades after the early boats were built. You could say, we have modern expectations.
~ green ~ lake ~ ~
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Re: Centerboard rocking side-to-side

Postby VTDS2 » Tue Sep 07, 2021 12:06 pm

This is reassuring - I wasn't excited about the idea of centerboard work as a fall project.
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Re: Centerboard rocking side-to-side

Postby tomodda » Tue Sep 07, 2021 4:49 pm

If the centerboard's rockin', don't come knockin'! Sorry, couldn't help myself... :)

Seriously, it's like GreenLake and John wrote, all CB's rattle around a bit, especially if no wind. Solution? Sail faster! Water pressure will shove the board up against it's pin. No reason to worry.

I daysailed a lovely little Beetle Cat this summer, an old wooden beauty. Every time I got her up to speed, the board would start humming, and I was sure I had caught some seaweed or whatnot. So I'd yank the board up and shove it back down and it would stop humming for a while then start up again. When I got back to the dock, I thanked the owner for letting me borrow her for such a fun sail, but I told him about the humming centerboard. He said to me: "Oh! That just means she's happy! Let her be!"
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Re: Centerboard rocking side-to-side

Postby GreenLake » Tue Sep 07, 2021 10:19 pm

Humming/thrumming or vibration at high speeds: taper the rear edge and cut it off so it's 1/16" to 1/8" wide. But angle the cut a bit, to prefer one side. The board will change the way it sheds vortexes and stop vibrating.
~ green ~ lake ~ ~
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Re: Centerboard rocking side-to-side

Postby tomodda » Wed Sep 08, 2021 1:08 pm

Yes, squaring the trailing edge like GL describes will definitely stop the hum. My DS 1doesn't have that problem, thank goodness. As for the Beetle Cat, it's a great boat, but essentially a floating sofa with a big mast. Getting her "up to speed" is very relative and the added drag of a humming CB is nothing compared to her big fat bottom... that didn't sound right at all! ;) Anyway, "She hums when she's happy" is a nice poetic explanation, who can argue with poetry?
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Re: Centerboard rocking side-to-side

Postby GreenLake » Wed Sep 08, 2021 2:00 pm

This forum is missing a "like" button. Yes, on the poetry.
~ green ~ lake ~ ~
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Re: Centerboard rocking side-to-side

Postby Anstigmat » Wed Sep 08, 2021 4:04 pm

I shimmed mine by making a large PVC washer on one side. Conventional wisdom was to do 2 washers but I took an easier route. No issues this year! No noises, works well.
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