# In-mast furling noise



## turbulicity (Jan 24, 2011)

It has been just over a week since I pulled my new boat in the marina. It has hood in-mast furling. The prevailing wind is from astern and the mast is making quite a noise. As expected, today I was notified that the neighbors are complaining.

I believe there are a couple of ways to remedy this howling noise.

1. Hauling up a sailcloth strip (called flute stopper) through the slot
2. Chafing strips added to the edges of the slot (this one I learned from Don Casey at: http://www.sailnet.com/forums/gear-maintenance-articles/20009-howling-masts.html )

I can't find any more information about these methods other than what they are called. Could anyone who has one of these post a few pictures or a better description? Would be great to find out makers of such "chafe strips". I think I could make the "flute stopper" myself if I knew what it looked like.

Thanks


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## Pamlicotraveler (Aug 13, 2006)

I don't know how to fix it, but I have heard some Benetau's with this problem in a major way. And I mean BRAND new boats. It sounds like a motor is running, but if you put your ear to the mast you could tell it was something in the mast.


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## turbulicity (Jan 24, 2011)

Yep, it can get pretty loud. The wind recirculating in that sail cavity is the culprit. I will try furling the sail loosely and/or slackening the halyard but I don't think these will completely get rid of the noise.


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## sailingfool (Apr 17, 2000)

turbulicity said:


> .. I will try furling the sail loosely and/or slackening the halyard but I don't think these will completely get rid of the noise.


in my use of in-mast furling, I have understood these as being opportunities to jam the sail...


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## turbulicity (Jan 24, 2011)

sailingfool said:


> in my use of in-mast furling, I have understood these as being opportunities to jam the sail...


I am worried about that, but it will take some time for me to get a "flute stopper" or that other thing made. I don't want to be known as "that guy with the annoyingly noisy boat" around the marina. My first bet is to turn the boat around so she faces the wind most of the time. Maybe that will do for a while.


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## poopdeckpappy (Jul 25, 2006)

Our other boat is a 45CC with Seldon in-mast; had a problem with a loud vibrating hum in high winds, I wrapped a sail tie off our tayana around the boom and outhaul on the 45CC and solved the noise issue.

Took a while to pin point exactly where it was coming from cause it sounded like the whole rig was humming


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## Liquorice (Nov 28, 2007)

As a temporary measure, can't you turn the boat around so the prevailing wind comes in from the bow?
sam


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## Liquorice (Nov 28, 2007)

Ignore my last comment, I've just reread your last comment - Duh!!!


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## Minnewaska (Feb 21, 2010)

Our rig will hum like a tuning fork in high winds if the main sheet has been cranked down on the boom. Typically, before furling back in, the main sheet is tensioned to pull the boom to the center, but becomes much too tight once the main is furled. It's bizarre, but all we need to do is relieve the tension by unlocking then relocking the clutch, which lets maybe 2 inches of line through and the boom has a little bit of play side to side.

Yours may not be this simple, but thought I would pass it along, just in case its as simple.


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## turbulicity (Jan 24, 2011)

Just turned the boat around and also slackened the mainsheet a little as Minnewaska suggested. I don't know if these will do the trick as there wasn't much wind to make noise anyway today. 

I don't quite understand what the boom has to do with the noise though. The sail cavity in the mast is the source of the noise. But I have seen suggestions before about lifting the boom a little and so forth. Maybe these are changing the natural frequency of the whole setup somehow so the resonance doesn't happen at that particular wind speed anymore. When the wind speed changes, the noise should come back at some point.

Back to the original questions, can anybody who has a "flute stopper" cloth post some pictures? 

Thanks a lot for all the help.


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## Minnewaska (Feb 21, 2010)

It must be a resonance issue on mine. Mine sounds more like a tuning fork that a wind whistle. You can hear it all around the boat, its very loud. Open the clutch and it instantly silences. Very odd.


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## turbulicity (Jan 24, 2011)

I just moved to my permanent slip two days ago. Turning the boat around on the guest dock before had solved the noise issue completely. Using the same method would mean backing into my new slip which is not easy or practical in this marina. So, back to square one.

I played around with the boom, mainsheet, main halyard tension, outhaul in various ways. I got the noise a little down but it is still noisy enough to bother us and everybody else in the marina. 

I talked to a sailmaker today and asked if he knows about the so-called flute stoppers. He doesn't. We came up with a design in which two 5/8 lines would be sewn to both ends of a 5' sail tape. I would then slide in one of the lines to the groove, the other stays out, and haul the thing up the mast groove to essentially plug the whole groove. I feel this could work but I will need to unfurl the main a little to get the line into the cavity from the bottom. 

At this point, I would like to ask if anyone have a description/picture of a flute stopper so I can have it made properly instead of a makeshift design. Thanks in advance to anyone who can share any information or reference.


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## sailortjk1 (Dec 20, 2005)

> It must be a resonance issue on mine. Mine sounds more like a tuning fork that a wind whistle. You can hear it all around the boat, its very loud. Open the clutch and it instantly silences. Very odd.





> I played around with the boom, mainsheet, main halyard tension, outhaul in various ways. I got the noise a little down but it is still noisy enough to bother us and everybody else in the marina.


I have found the culprit to be the toping lift. When we crank down on the main sheet too much we get the hum. Next time it happens, put your hand on the topping lift feel the vibration and listen for the noise. Stop the vibration and see if the noise goes away. I found it by chance. Don't know if either of you are hearing the same but on our boat the noise does not come from the mast slot.


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## turbulicity (Jan 24, 2011)

It is hard to say where the noise is coming from exactly. Loosening the mainsheet didn't help though (mainsheet car banging on the stoppers was some added noise). So, I assumed loosening the outhaul would be about the same thing. I will try anyway.

Yesterday, I wrapped a tarp around the mast, tied the two ends to make a loop and hoisted the thing up the mast up to the spreaders' level. That didn't stop the noise either. I think most of the noise is generated towards the mast tip when the wind is blowing near directly into the sail cavity.


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## dhays (Jul 9, 2010)

I have inmast furling on my C400. With wind from the right direction and speed, we can get the noise you are talking about. I think each rig will be unique. It hasn't been so loud as to be annoying for us yet, but I can see the potential would be there.

While I've heard of flute-stoppers, I've not seen anything specific. I think you and your sailmaker on on the right track, two tapes sewn together, one on the inside and one on the outside.


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## turbulicity (Jan 24, 2011)

dhays said:


> I have inmast furling on my C400. With wind from the right direction and speed, we can get the noise you are talking about. I think each rig will be unique. It hasn't been so loud as to be annoying for us yet, but I can see the potential would be there.
> 
> While I've heard of flute-stoppers, I've not seen anything specific. I think you and your sailmaker on on the right track, two tapes sewn together, one on the inside and one on the outside.


Well, what we are thinking about is slightly different. We are thinking of using two ropes sewn on each end. I heard about the two cloth strips sewn in the middle before but how does that stay in the groove? Wouldn't wind easily take it out of the cavity?


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## dhays (Jul 9, 2010)

turbulicity said:


> Well, what we are thinking about is slightly different. We are thinking of using two ropes sewn on each end. I heard about the two cloth strips sewn in the middle before but how does that stay in the groove? Wouldn't wind easily take it out of the cavity?


If the tapes were stiff, I wouldn't think so, but you never know. Your idea would work fine as well, although probably a bit more spendy to make.

Dave


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## JimsCAL (May 23, 2007)

All this confirms my decision to cross off any boat with a mainsail furling system from further consideration during my recent boat search. My "new" boat came with a Dutchman system and I must say it works pretty well. When it comes time to replace the main I will definitely go with the Dutchman system again but not sure about all full length battens again or just one or two.


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## capecodda (Oct 6, 2009)

*some whistle, some don't*

I had a Hood inmast furler that was quiet in a previous boat. My neighbor has one that loves to whistle when the wind comes from the stern. Makes a LOUD hum. I'm not sure about this but I think my sail fit tighter in the mast than his, so there was less space to let the wind whistle through. He's not in the water yet, so I don't have a picture to help you with. I think this effect (whistle) is different from the hum that you get is some non-furling rigs when some resonance sets up. It really is from the wind whistling through the aperture (like blowing across the mouth of a jug), and can be unbelievably LOUD.

I think the flute stopper blocks the aperture on the mast with a thin strip of sail cloth. There is a halyard for this. I'm not sure what holds it in place in the aperture, although I've hauled it up for him (my excuse is old age). Somehow it grabs the edge of the aperture.

One idea would be to call the Hood (now Hinckley) folks in RI. Someone there has experience with these flute stoppers and could probably advise you. In the next few weeks, when my neighbor's boat shows up, I'll take a look at his setup and advise. PM if you'd like.


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## night0wl (Mar 20, 2006)

turbulicity said:


> Yep, it can get pretty loud. The wind recirculating in that sail cavity is the culprit. I will try furling the sail loosely and/or slackening the halyard but I don't think these will completely get rid of the noise.


Do *NOT* do this...recipe to jam your sail on the next time you unfurl. Ask me how I know? The Beneteua/US Spar system on my B343 is extremely sensitive to loose wraps and a loose wrap will bulge and jam, causing much pain and agony


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## turbulicity (Jan 24, 2011)

I called the hood (sailmakers now) and got some information about the so-called flute stoppers. It seems there are two kinds:

1. Two 5" strips of 8.5 ounce dacron sail cloth sewn together in the middle
2. This version uses buttons that slide into the groove instead of the second cloth.

They said the masts usually have a halyard block at top for the flute stopper and that halyard comes down from outside the mast. I don't have that halyard but I have one for spinnaker. The problem is that the spinnaker halyard will pull the flute stopper a little sideways and may pull it out of the slot. The button version would work better in that case but the buttons are not available anymore. I will either find a suitable alternative for the button or go with the bolt rope.

On the plus side, I created a new favorite topic of conversation in the marina. Everybody now can get together and hate me.


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## Silvio (Nov 10, 2010)

turbulicity said:


> On the plus side, I created a new favorite topic of conversation in the marina. Everybody now can get together and hate me.


OUCH!
Good luck getting it to quiet down. FWIW when I moved to a new marina I had a similar issue. Drove me and the neighbors batty for about two days until I chanced on the fact that the humming was being generated in the boom even though it sounded in the mast. Cranked the boom all the way over using the traveler and has been quiet since. Even had a neighbor offer me a cold one recently, talk about proof huh?


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## turbulicity (Jan 24, 2011)

Silvio said:


> OUCH!
> Good luck getting it to quiet down. FWIW when I moved to a new marina I had a similar issue. Drove me and the neighbors batty for about two days until I chanced on the fact that the humming was being generated in the boom even though it sounded in the mast. Cranked the boom all the way over using the traveler and has been quiet since. Even had a neighbor offer me a cold one recently, talk about proof huh?


Just tried that last night and didn't work. Fortunately it has been somewhat less windy yesterday so we didn't bother anyone much. It is time to order that flute stopper thing.


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## turbulicity (Jan 24, 2011)

I ordered the flute stopper I described and it should be ready sometime this week. But, the noise was the worst yesterday. We couldn't stand it and in a moment of desperation, I got rid of it. Here is how:

My jib halyard is a 5/8 inch line. It is larger than the slot in the mast. I tied a thinner nylon line to the bitter end using fisherman's hook. I slid the end of the jib halyard through the bottom of the slot, thinner rope sticking outside. Then I tied the thinner line to spinnaker halyard and hoisted up. Spinner halyard of course faces forward so towards the top, it pulls sideways. But it went most of the way up and the noise is gone (By the way, the noise got progressively louder as I was hoisting until up to the spreader's level. It was like someone grinding the mast.) The only risk is if the fisherman's hook releases, my spinnaker halyard it stuck at top so I would need to climb up the stick.

I will still go ahead with the flute stopper contraption. This could be a permanent solution if I could splice the thinner line instead of tying but I was told I could only do that with a new braided line which would be about the same cost anyway.


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## Clarity2 (Jan 12, 2011)

*Flute stopper*

I don't have a pic of the one for my boat but can describe it. My rig is a Hood Seafurl on a 42 footer, btw. Without the stopper, wind around 15 degrees abaft abeam sets up a howl that would raise the dead.

Stopper is a very stiff piece of fabric (feels like it's super-heavily starched, but I guess it's some sort of plastic-impregnated canvas) that is a little wider than the slot in the mast, maybe 3 inches, and with what look like oversized plastic buttons (like maybe from a woman's coat) every 18 inches or so. There's a brass grommet at each end. You thread the canvas inside the mast and the buttons stay outside (they too are a little wider than the slot) and hoist it with a spare halyard through the grommet, tensioning with a piece of small stuff as a downhaul through the grommet at the other end.

Don't know what kind of rig you have but the manufacturer can probably provided you with something like this.


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## turbulicity (Jan 24, 2011)

Thanks for the detailed description. Yours is one of the two designs I know of now. I order the other one (another layer of cloth instead of the buttons). I think both would work equally well. It was easier and cheaper to go with the two layer cloth design. My jib halyard inserted into the mast slot completely silenced the noise. I will post an update once I hear from the sailmaker.


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## Mikabo (4 mo ago)

It's all about the groove. It won't happen if you're on a mooring or anchored pointing into the wind. The intensity will vary with the volume of the sail cavity (tightness of the furled sail). My 'whistle stop' is a 55 foot length of a densely woven 4 inch sail material with flexible plastic discs fastened a couple of inches apart on the inside that are inserted above the clue gap. It has a separate lightweight halyard that hooks to the hoisting end with a grommet. Guide the discs inside the groove above the clue gap, hoist slowly and it blocks the gap. Silence! Pull down with a controlled halyard release, unclip, make fast and you're off.
A furling main without battens is a learning curve. Get the power curve right tune the headsail slot so the boat's pointing compromise is minimal and reduce sail in a tack if needed, (with a bit of timing) on a tack that keeps the sail from dragging over the slot edge (Starboard for a clockwise wind) . (My wife doesn't like the rail buried when she's cooking. ) Keep the grease cup stocked on the mast top and make sure the halyard run is a fair lead when you hoist in the Spring and furl with the boom up slightly so the bulk of the sail doesn't crowd at the foot.
DJ 60 years a sailor


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