Dagerboard/keel

Discussion in 'Sailboats' started by tamkvaitis, Apr 2, 2006.

  1. tamkvaitis
    Joined: Aug 2005
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    Location: lithuania

    tamkvaitis sailor/amateur designer

    I have bought or to be sure I have taken a sailboat (I paid for it 200 euros). It's dimensions are:
    L 5.5 m
    B 2.45 m
    D 1.3/0.3 m
    displasement about 0.7 metric tones
    SA upwind 18.5 sq meters

    It needs some repairs. Things about repairs are quite clear for me, but I have an Idea. It uses balast placed on the botom of the boat (I don't know how to name it) and it has a dagerboard. I have an idea to put more weight to the dagerboard and remove some of the lead inside the boat. I would reinforce the dagerboard well If I would put more weight on the dagerboard. What do you think about this idea?
     

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  2. SailDesign
    Joined: Jan 2003
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    SailDesign Old Phart! Stay upwind..

    Tam,
    If you dd weight to the daggerboard, you will increase the righting moment, which means you may also need to increase the strength of the mast and rigging, and the chainplates.
    You should look into it very carefully before investing time or money.
    Steve
     
  3. Windvang
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    Windvang Yacht Designer

    Probably not much of a problem at this size of boat, as crew weight is a far bigger influence on righting moment. You can compare sizing of mast and rigging to Micro class sizes to be sure. It won't hurt to beef up the daggerboard case a bit though. EU 200 sounds like a good deal!
     
  4. tamkvaitis
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    tamkvaitis sailor/amateur designer

    I would design weigt of the dagerboard in the way that the RM would keep the same.
     
  5. Windvang
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    Windvang Yacht Designer

    That would probably still require beefing up the centreboard casing and pivot point.
     
  6. tamkvaitis
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    tamkvaitis sailor/amateur designer

    I named it wrong. The key of this idea was that the dagerboard casing needs repair anyway, so why not to rinforce it more and use balast more efectifly.
     
  7. messabout
    Joined: Jan 2006
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    messabout Senior Member

    Iy you add a useful amount of weight to the daggerboard, you will need to consider the added difficulty of raising the board. I presume you have thought of a suitable method for lifting the board.

    The total effect of your idea sounds good. You may be able to keep the same righting moment with less total weight. That is usually a worthy goal.
     
  8. solrac
    Joined: Feb 2006
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    Location: 34'54"35"47S - 56'07"48"98W

    solrac 100% sudaca

    hi tamkvaitis, for what you say, & the photo it looks a lot like a Laser 660 I used to sail, I remember it's weakest point was the keelbox screw & bolt, there is no way to assure the leakproof of the keel box as stated in the manual. we used to have a 12 pump with a simple automatic electronic device to control it (stinky yeah? but works):D
     
  9. tamkvaitis
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    tamkvaitis sailor/amateur designer

    It' is russian boat, but I think it may have a lot of in common with laser o r other similar boat, becaus Soviet's had huge industrial spyng campaign. Dagerboard casing is solid with the hull, it leaks in the place where it was hit while trailering.
     
  10. solrac
    Joined: Feb 2006
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    Location: 34'54"35"47S - 56'07"48"98W

    solrac 100% sudaca

    ok, if they have well done their homeworks, surely it can be repaired from inside, under the floor panels, (surely yoy can access to the fiberglass) maybe adding a couple extra reinforcements, similar to the ones it must have to ridgidizate the keelbox.
    Here, we use to repair this kind of damage with some plastic angle/tube + reinforced in fiberglass, (the plastic piece only to perform a reasonable "beam form" covered with roving/resin)
     

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  11. tamkvaitis
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    tamkvaitis sailor/amateur designer

    Thanks for the image.
    The dagerboard quite narow, then lowered, so I think to add one reinforcement prety much similar to the one you have shown, only diference is that it would be done with plywood. I will post some pictures from the inside of the boat. you will see the whole picture.
     
  12. yokebutt
    Joined: Aug 2004
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    yokebutt Boatbuilder

    Careful there, lightening the boat makes the waterline narrower, wich also reduces the RM.

    Yoke.
     

  13. tamkvaitis
    Joined: Aug 2005
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    tamkvaitis sailor/amateur designer

    a litlle drawing of the boat
     

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