| Rossiter Pintail Mortagne sur Gironde, near Bordeaux |
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| Laser 28 - Excellent example of this great design Hamble le rice |
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| Laser 140101 Tynemouth |
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List classes of boat for sale |
Howling Boats |
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NickA 
Really should get out more 
Joined: 30 Mar 05 Location: United Kingdom Online Status: Offline Posts: 784 |
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 Topic: Howling BoatsPosted: 05 Oct 06 at 2:42pm |
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My lovely new boat howls when it planes. When it really gets going a second pitch kicks in and it howls in harmony. An F18 cat I once knew was so loud you could hear it take off from the club house! I quite like it ... but it's probably going to be really annoying to everyone else, plus all that noise must be robbing energy. Anyone else had this "feature" and cured it? |
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Black no sugar
Really should get out more
Joined: 04 Dec 04 Location: Somewhere between Brighton and Lancing Online Status: Offline Posts: 3941 |
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Posted: 05 Oct 06 at 3:26pm |
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Laser4000s sing in a variety of pitches depending on the wind and the crew. Having one of those screeching things appearing out of nowhere when you're in a Topper in a force 6 is an experience to remember!
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furtive
Posting king 
Joined: 30 Mar 05 Online Status: Offline Posts: 188 |
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Posted: 05 Oct 06 at 3:34pm |
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On Laser 4000s, this is caused by having a big fat trailing edge on the daggerboard (and rudder). Class rules allow you to sand down the back 75mm of both foils to make the trailing edge finer. This stops the high speed humming, presumably saving a bit of lost energy, but does make your foils a bit more fragile - be careful of the trailing edge if you capsize and are standing on the board. Foils made in the same way (ie other Laser boats) probably have similar issues, and also probably have the same allowance in the class rules as they all originiated in the same place. More hi-tech foils are probably designed/made to avoid this problem in the first place! |
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Jamie600
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Joined: 14 Jun 05 Online Status: Offline Posts: 718 |
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Posted: 05 Oct 06 at 3:37pm |
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The back edge of one or both of your foils is vibrating. Try sanding to a finer point if your class rules allow it, should make it go away |
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Guest
Newbie 
Joined: 21 May 04 Location: United Kingdom Online Status: Offline Posts: 0 |
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Posted: 05 Oct 06 at 4:23pm |
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Boat that do that really annoy me. The way to fix it is to make sure your foil is free of imperfections and sharpen the trailing edge ... Somtimes an assymetric trailing edge is needed. Rick |
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49erGBR735HSC
Really should get out more
Joined: 30 Mar 05 Location: United Kingdom Online Status: Offline Posts: 1991 |
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Posted: 05 Oct 06 at 4:33pm |
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We had a similar problem with the 5000, fairing the foils appropriately helps but there could also be areas on the mast which are causing the humming noises. The 5000 has a hole at least a few centimetres diameter bored into the top of the mast, so in big winds it used to hum and whistle. We simply taped it up, also preventing the boat from inverting so quickly when we decided to go swimming... We do experience mild humming when sailing at speed but it is from the windage coming off the rig and it's easy to distinguish that sort of humming compared to humming caused by innadequate fairing. |
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m_liddell
Really should get out more
Joined: 27 May 05 Location: United Kingdom Online Status: Offline Posts: 583 |
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Posted: 05 Oct 06 at 7:34pm |
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The 5000 humms lounder than any boat I've ever sailed, it's really really loud. I fixed the hum on a laser buy replacing the pathetic bolt on the stock with an big fat bolt tightened up so that it was effectivly a fixed blade. Sailed a buzz that hummed from the shrouds which was weird. Some windsurf rig/board combos humm too. My 14 is silent |
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les5269
Really should get out more
Joined: 11 Oct 05 Location: United Kingdom Online Status: Offline Posts: 1530 |
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Posted: 05 Oct 06 at 7:37pm |
Your sailing the wrong 5000's then. My old one never hummed at all and my helms is just as quiet |
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49er 531 & 5000 5025 and a mirror(now gone to mirror heaven)!
Grafham water Sailing Club The greatest inland sailing in the country |
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Medway Maniac
Really should get out more
Joined: 13 May 05 Location: United Kingdom Online Status: Offline Posts: 2788 |
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Posted: 05 Oct 06 at 9:03pm |
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Noise generation requires very little energy, but the vibration might have undesirable effects on the boundary layer and consequentially on skin friction drag. Instead of simply thinning the trailing edge, you might like to try the solution proposed by United Technologies Corp in US Patent 4786016: Use of patented subject matter is free for individuals for personal use. |
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Merlinboy
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Joined: 03 Jul 06 Location: United Kingdom Online Status: Offline Posts: 3169 |
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Posted: 05 Oct 06 at 11:31pm |
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My laser used to do it back in the ay! Oh how i miss her! I used to have a knact slot gasket on my phantom that cause a fountain when you planed it was annoying because when you are hanging off the transom for dear life it would land right in my face - blinding me not good!!! |
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