Redesign a motor boat to a sailboat

Discussion in 'Sailboats' started by Karsten Jessen, Aug 7, 2019.

  1. Karsten Jessen
    Joined: Aug 2019
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    Karsten Jessen New Member


    I am thinking about making a new boat i can live on, and have found some plans for a nice end spatial interior.
    Only problem is that it is a motor boat.

    Thats why im wondering if someone can help me redesign it?
    I have made a 22' sailboat before from already existing plans :)

    Attached Files:

  2. TANSL
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    TANSL Senior Member

    Forget the shapes of that ship at all. Make an outline of the interior space, as you wish, write an SOR and have someone to design a sailboat around it.
  3. KeithO
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    KeithO Senior Member

    Karsten, that is a planing hull. In any practical configuration, you are unlikely to be able to manage a sail rig big enough to get such a hull to plane. If you examine the original boat you will probably find twin engines of 500hp plus capacity, perhaps even more than 1000hp. Below planing speed, the hull will generate considerable drag. Sailboat hulls generally look the way they do for a reason and that is to part the water as efficiently as possible at low speed (usually less than 10kts). The more efficient the hull, the less power is needed and the easier it is to manage the sails. Any sailboat needs a keel to counteract the forces generated by the wind on the sails or it will capsize or lean over so alarmingly that sailing would be impractical. Attaching a heavy keel to an existing hull is no small undertaking.
  4. wet feet
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    wet feet Senior Member

    In the words of the old piece of advice "If I wanted to get to there,I wouldn't start from here." Not remotely feasible or sensible when so many boats that fit the intended criteria are available for quite low prices.
  5. Ike
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    Ike Senior Member

    It won't say it's impossible. I turned a 14 foot outboard boat into a sailboat way back in the early 60's, but it never did sail right and wouldn't go upwind worth a damn. That boat is designed for one thing, going fast with big engines. You need to start with a more practical design for sailing.
  6. kapnD
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    kapnD Senior Member

    If you put a mast on that hull, the smallest puff of wind will roll it over, even with no sails up.
    If a heavy, deep keel is in$talled to counteract the mast, it will possibly hold it upright, but it will sail miserably.
    The existing rudders would be ineffective under sail too.
    I’d shop for a sailboat, if that’s part of your SOR!
  7. Deering
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    Deering Senior Member

    Do you actually want a boat that you can sail? Or just to live aboard? If the former, run, don’t walk, away from such craziness.
  8. KeithO
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    KeithO Senior Member

    If I'm not mistaken, the image he used is of a PT boat from WW2 ???
  9. TANSL
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    TANSL Senior Member

    In both cases, in my opinion, "run away from such craziness"
  10. gonzo
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    gonzo Senior Member

    Yes. Those boats carried 3 or 4 Packard engines of 1,200 HP each.
  11. TANSL
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    TANSL Senior Member

    Gonzo, then, according with these engines, the transformation is or it is not possible?
  12. sharpii2
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    sharpii2 Senior Member

    I agree with just about every comment here except the one about it being knocked over by a puff of wind. By the looks of it, it has substantial initial stability. If the huge engines were removed and replaced by ballast, even sandbags, it would have an even greater range of stability. I have thought about the problem of turning a former planing powerboat into a sailboat for some time. The simplest and cheapest way would be to cause some bow-down trim. This would leave less of the draggy transom under the water. After that or instead of that, a stern extension could be added which could reroute the water flow up to the surface, as most non-planing powerboat and sailboat hulls do.

    But this is a huge boat, and this would be a major undertaking which would require thousands if not tens of thousands of man-hours. And there is no guarantee it would work out well if at all. A project like this would be more like a billionaire's bet than a reasonable proposition.
  13. rnlock
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    rnlock Senior Member

    First, cut off the aft half and replace it with something more like a sailboat. Then do the same to the forward half. ;-)

    I think if you look around you will find a design with a good interior that would also sail reasonably well. But you should expect it to have much less room than a house, or to be so large that you'll need to hire people to help you finish it in any reasonable amount of time. I know his name is mud around here, but Bolger has done some larger designs with amateur builders in mind. For instance, I think his AS39 is meant for amateur builders. If that's too ugly, maybe his Resolution. I understand he lived on that for a while.

  14. pitcha
    Joined: Dec 2004
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    pitcha Junior Member

    Dear Karsten,
    I could made this design for you. It seems I have seen this boat in Denmark few years ago and also thinking about liveaboard sailer on her hull.
    If it's still actual, drop me please message to pichakhchi gmail com for the concepts
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