Daggerboard rattles whole boat when on any tilt or good speed

Discussion in 'Sailing Talk' started by my old puffer, Jun 1, 2010.

  1. my old puffer

    my old puffer New Member

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    Does any body out there know this problem? I bought a early 70's "Puffer"..if not familiar, it was made by AMF and it was just thier tub version of the sunfish but with a jib...totally the same rig and all (rutter and daggerboard, I think)....I totally refinished the boat and painted it..after it was all said and done i took it out for a sail...sails great but if you put any good sail behind it, the daggerboard rattles so bad it sounds like it doing damage to the hull/dagger box..not that i am trying to heel-over this boat, but it would be nice to push its limits or have any good speed in that matter...but i know that it is not a good idea for the dagger box or hull...i bought it from a guy who didnt know anything about it..the dagger could be the wrong one/right one..thats all i can come up with...only problem is that its a good fit through the slot...it self rises also, which i find odd....can anybody help with this? the session is appon us and its time to sail :)
     
  2. Wayne

    Wayne Member Emeritus

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    [​IMG]


    Your daggerboard might fit snuggly through the wood top cap, but fit loosely in the daggerboard trunk itself.

    To exacerbate things, a daggerboard that's not well faired (smooth and symmetrical) will want to flutter at speed. All daggerboards and rudders will find a point where they will vibrate in a sympathetic harmonic fashion.

    You can buffer the vibration by contact cementing I/O carpet strips vertically inside the daggerboard trunk.

    [​IMG]

    .
     
  3. my old puffer

    my old puffer New Member

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    Thanks!! I thought about maybe foam would help, but carpet makes more since! Thanks again!:D
     

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  4. pez

    pez Member

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    Some dude has one of these at our lake... he has fewer teeth than this boat has sails... While I cant specifically tell how it is supposed to be rigged I know he is doing it wrong. I offered to give him a hand and he refused... looks like it's a fun boat for what it is...
     
  5. my old puffer

    my old puffer New Member

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    Well Pez, don't feel bad. He apparently doesn't take advice from anyone, especially his dentist by the way it sounds...ya, she is a little fun one. I live a block from the ocean, so i launch her off the beach. not something ya want to push when there is a swell ;) or ya might want to bring a bunch of bilge pumps and batteries
     
  6. uid100

    uid100 New Member

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    Closed cell foam strips might be a better choice since they won't soak up and hold water like the carpet strips will. That may dampen the vibration some, but likely won't eliminate it. The cause is more likely the shape of the board itself. Is there any foil shape to the board at all? Maybe a curved leading edge and (more importantly) a sharp(er) trailing edge? Can you sand a nice streamlined shape into the board without spending too much time/effort?

    Cavitation will cause the whole boat to vibrate. Trying to dampen the vibration by holding it tighter may help, but reducing the vibration if you can is a better solution. Also, I can just imagine pulling pieces of carpet through the water as it breaks down and starts hanging off the bottom of your boat.

    http://www.aerospaceweb.org/question/aerodynamics/sports/sphere-airfoil-comparison.jpg
     
  7. my old puffer

    my old puffer New Member

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    uid100, the board has niether a leading or a trailing edge..well, they are all the same...its a flat dagger with bullnosed edges...i run a custom metal shop but my buddy owns a custom wood furniture shop. I was trying to see if there was any other advice before i take it to his shop and shape a whole new one. Does anybody have a photo or idea what it should look like in "plan"? uid100, im a bit timid on sanding down the board at all since i feel it may be to small already
     
  8. uid100

    uid100 New Member

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    Try cutting a V-shape into the last 3/4" or so. It doesn't have to be sharp, and doesn't have to be pretty. I would just get the trailing edge to be more of an edge and not worry about the rest of the board. Keep the changes minimal and then throw it back in the water. If it gets better, you're on the right track.
     
  9. Wayne

    Wayne Member Emeritus

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    If...IF... it sets the same as the board for a Sunfish, the photo I swiped from Sailing Texas for my earlier post shows the boards orientation..., the slight angled part of the end curve goes forward. <shrug> Try it both ways, some Sunfish sailors claim just the opposite works better for them.

    You could see if the Sunfish profile is close to what you have. Look in the racing rules for specs. pp 7 & 9 of the pdf file...
    http://www.sunfishclass.org/archives/2006/ISCA_CLASS_RULES_20052006.pdf

    If you are making a new one, grab the new Sunfish design. It's a real improvement over the flat board of yesteryear.

    There's an owner's support group. They may have more info.

    http://groups.yahoo.com/group/amf_puffer

    .
     
  10. Wayne

    Wayne Member Emeritus

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    Mine doesn't wick up water when I'm sailing and hasn't held water or grown anything slimy in over 15 years. It's a door mat cut into 2" strips and the synthetic nap sheds water pretty well.
     
  11. uid100

    uid100 New Member

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    I stand corrected. This may be all you need. Definitely consider the easiest, simplest, cheapest solution first. And remember that if your quest for a solution leads you down the path of hiring an engineering firm, and using exotic materials, and expensive shop time, you might want to start out with a different boat. :D
     

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