Humming Mast

[ex-Gladys]

used (many moons ago) to sail on a friends dad's Iroquois Mk 1 cat, and the rudders and centreboards would do that. Reckoned to be to do with the shape of the trailing edge... IIRC, if it's too sharp it'll hum,needs to be squared off...

<hr width=100% size=1>Larry Botheras

Anderson 26 "Amber"

 

[bruce]

have heard that the sharp edges could, but don't have slightest idea why i brought up the keel, thought someone had brought it up, sorry...

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[nicho]

This shaking is not uncommon evidently, and is caused by the wind blowing from a certain direction setting up harmonics around the mast, which then gradually increases until the mast actually pumps back and forth. Selden evidently market a long piece of flexible plastic, about one and a half inches deep that runs up the masts spare channel - this breaks up the windflow and the problem goes away. I have had this shaking phenomonen a couple of times whilst in my berth (No, the mast, not me!)and asked Selden about it at the SBS. It has not done it again, so I never bothered with their cure.

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[surekandoo]

That could be the keel lift wire. Try running it slightly slack when the keel's down. I used to have that problem on a Jaguar 25 but only when going above 5 knots, which wasn't very often!!

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[MainlySteam]

Having the mooring lines without a reasonable amount of slack in them in a berth where the boat is restrained (especially if in all four corners) can greatly accentuate shaking (but not humming). If the lines have more slack allowing more movement the hull will dampen the shaking as the energy is transferred into non violent hull motion.

John

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[joe17]

Try wrapping the halyard round the mast

My mast does the same. Hums and vibrates when the wind is at the right speed and angle.

The former owner warned me about this and he told me his cure had been to take the main halyard and wrap it around the mast a few times and then fix it and tighten it. He said that had got him back to sleep many times. I havent tried it yet.

I also experienced the humming topping lift yesterday on the way back in. The topping lift and main sheet were really tight and all it took was a bit of slack on the main sheet and all was quiet.

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[BrianJ]

On behalf of those of us from OZ.. we are all being very good and not buying into this one...but it does lend itself to remarks about Poms , showering once a week etc..etc.. to te extent that even your masts " hum " ..
Gee we are kind to you all.. only because of what happened 60 years ago this weekend....
brianJ

<hr width=100% size=1>BrianJ