Humming Mast

[CharlotteRusse]

Does anybody else's mast hum?

In light winds, the kind often experienced at night whilst trying to sleep, my mast (Moody 29) sets up a low resonance that sounds a little like a squadron of lancasters going overhead (probably). This hum transmits itself through the coach roof and rigging and generally makes a blumin nuisance of itself. It was so bad on Saturday night at Newtown Creek that I could swear I saw several of my neighboring anchorers looking quizically skywards!

Any ideas?


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[VicS]

Are you sure it's the mast? On my boat it's the topping lift if it's tight. It took several years to discover the cause but now I slacken the mainsheet a little at night.

<hr width=100% size=1><font color=purple>Ne te confundant illegitimi.</font color=purple>

 

[claudio]

Possibly the rigging resonating, do you have an adjustable backstay that you can take the tension off slightly at night?
Failing that, try hanging some washing /forums/images/icons/smile.gif (towels e.t.c) on the rigging so that they dampen out the resonance.



<hr width=100% size=1><A target="_blank" HREF=http://shop.yachtronics.co.uk>http://shop.yachtronics.co.uk</A>

 

[alahol2]

As VicS says, almost certainly the topping lift, loosen the mainsheet and sleep tight.

<hr width=100% size=1>I really would rather be sailing...

 

[AlexL]

Yup, Topping lift on mine too, Slacken off the mainsheet till it goes away.

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[snowleopard]

other boats with my type of mast get a loud whistle when the wind strikes the sail track slot at a particular angle, the designer ended up issuing a strip of cloth with two boltropes 1 inch apart to be hoisted up the groove when it happened.

funnily enough, mine doesn't have that trouble, perhaps due to slightly different shape of trailing edge.

when it happens, you might try interfering with the air flow over any holes in the mast: tape, string, bits of cloth etc until you find something that affects the noise

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[Talbot]

Under certain specific conditions, my mast not only hums, it actually shakes. very disturbing as I sleep with my head adjacent to the strongback under the tabernacle /forums/images/icons/crazy.gif

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[Bodach na mara]

Mine hums as well and the one on my last boat had a deep whistle! The hum on my present boat is not the topping lift but the roller genoa halyard, which I don't really want to slacken. The whistle was the mast acting like a giant flute when a certain strength of wind blew at a certain angle across the slots fer the rigging.

<hr width=100% size=1>Ken Johnson

 

[CharlotteRusse]

Interesting. I shall give that a try next time it happens. That may explain why it comes and goes - obviously I don't always have the mainsheet at the same tension.



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[ChrisL]

Nope, but my swing keel hums when sailing - any one got that one sussed?

Chris

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[boatless]

I actually quite like it when that happens, but if you finish the trailing edge off at 60 degrees (to the centre line) that should get rid of it. Confuses the vortices which roll off the edge alternately, promoting a vibration of the trailing edge...

<hr width=100% size=1>my opinion is complete rubbish, probably.<P ID="edit"><FONT SIZE=-1>Edited by boatless on 02/06/2004 13:53 (server time).</FONT></P>

 

[nct1]

It is quite often a piece of the rigging, on mine it was the topping lift.

Loosening the sheeting did not solve it, however tieing a rope from the topping lift to the rail did !

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[John_Clarke]

As well as easing the mainsheet check the kicking strap is slack.

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[jerryat]

Hi!

Loosening the mainsheet will not always cure the problem if it is, as others have suggested, and I suspect, the topping lift. To effect a definite cure, take the end of your mainsheet (or any similar size rope) tie a rolling hitch on the topping lift and slide it up as far as you can comfortably reach. Leave the rest hanging. This acts as a dampener and will entirely eliminate the noise. You do not have to ease the mainsheet at all using this method, so the humming noise is not replaced by the boom swinging from side to side and possibly creaking!

Sleep well!!

Good sailing!

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[towlerg]

It might be the topping lift - try tieing a j cloth to the topping lift a couple of feet up from the boom. Sounds daft I know, but it works on my Vega

George

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[dulcibella]

A humming topping lift drives me crazy as I generally can't remember the words.

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[nordic]

My topping lift sings too!

However, we use a boom strut at rest so the topping lift can be slackened off or taken to the mast.

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[ChrisL]

Yes its a happy little hum, I think I'll keep it.

Thankyou

Chris

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[bruce]

that is the keel cable either keel not down all the way, either way, it is the cable, loosen it to remove hum...

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[boatless]

Not neccesarily, my Laser did it and MGC27s do it, and they have a threaded rod.

<hr width=100% size=1>my opinion is complete rubbish, probably.