Sailing a pontoon boat

Discussion in 'Sailboats' started by pontoonsail, Nov 10, 2015.

  1. pontoonsail
    Joined: Nov 2015
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    pontoonsail Junior Member

    IMG_2358.JPG

    DSC00034.JPG

    IMG_2349.JPG

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    Pictures of the model
     
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  2. myark
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    myark Senior Member

    Its rare to see a pontoon boat with sails and congratulate you for your ingenuity.
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    The stern treatment of your pontoons could do with a taper that gives you much better results at the sail speeds, without compromising your higher speed motoring. You would be losing quite a bit of headway with the abrupt end you have.
     
  4. C-mack
    Joined: Jan 2010
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    C-mack Boat Dreamer

    Love this idea... keep dreaming... maybe I will have a dream like this too
     
  5. pontoonsail
    Joined: Nov 2015
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    pontoonsail Junior Member

    Pontoon sailing

    We really appreciate the comments and the humor.

    To help reduce the stern turbulence a new rudder is designed allowing the outboard to be raised out of the water while sailing. The stern of the pontoons will be altered with a simple cone which will reduce some drag and add some buoyancy.

    The windward pontoon digging in will need some sort of horizontal fin to give it lift.

    The solar powered blender is a problem at night and on cloudy days! We will work on improved solar panels next!! Maybe moon panels??
     
  6. myark
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    myark Senior Member

    Your idea of having a leisure boat that can float in shallow water for beaching and have the outboard motor as a speed boat or the fact you quietly sail around a favorite remote lake undisturbed economically and environmentally with no noise and have the deck level while under sail and not on a tilt like yachts do under sail is perfect a family boating experience.
    You lose a bit of sail performance but that's quickly adjusted with an outboard motor when no wind that can run rings around a yacht that has limited deck space.
     
  7. Alumination
    Joined: Oct 2013
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    Alumination Junior Member

    Oh, I know you are! :)


    This isn't helping.
    Think of this idea as a "gateway" boat to sailing.
    Folks try it.
    The ones who like it will want to make their "sailing" experience better and delve deeper into the sport.
    The ones who don't will not.

    See, this is helping.
    Evolving the design, improving the flaws, increasing efficiency within the design constraints.

    Won't the roof help the efficiency of the sail?
    Sorta like a "deck sweeping" design does, traps more air, prevents escape, etc.?

    I'd think a shorter sail which extends the entire length of the roof would help.
    Takes advantage of the roof.
    Lowers Center of Area.
    Might prevent the leeward bow from dipping.
    No need for a jib which encroaches on deck space.

    If you are gonna taper the back of the pontoons then could you also add a keel to eliminate the need for the dagger boards?

    Incorporate the rudder into the new tapered ends? Would 1 rudder be sufficient? Would 1 rudder mounted on just one of the pontoons still work?
     
  8. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    I like the single, near centerline rudder idea better. Part of the goal here, If I understand it right, is to have a boat that can quickly switch back and forth between power and sail modes. I'd also prefer it being rugged, even at the expense of some efficiency, so it could cope with submered tree stumps, rocks, and shifting sand bars, which are the lot of boats in small, "protected" waters. The near center mounted centerboard and rudder, in my sketch, are designed to kick up, if they hit something, and come most of the way out of the water when they are retracted.

    If its to be a true sailboat, it should be able to sail upwind reasonably well. This means the size and placement of the 'board(s) have to be reasonably accurate, in relation to the sailing rig. It's far better to have them slightly too far forward than too far aft. A little too large is better than a little too small.
     

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  9. pontoonsail
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    pontoonsail Junior Member

    Happy Thanksgiving

    Some comments about suggestions

    The overriding idea was to make the sailing simple and safe. The idea of a boom on the jib might pose a safety issue. The jib foot is intentionally high (4 ft) above the deck for visibility.

    The lee boards are simple and pick up easily for beaching.

    The single rudder is offset about 2 feet and can be lifted out of the water again for beaching. When sailing, the outboard is lifted out of the water.

    The cones on the pontoon sterns are being "designed". The idea is to have them add extra flotation?
     
  10. myark
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    myark Senior Member

    Your keel system that folds up is perfect and simple solution which I have seen on small flat bottom sail boats and older style large yachts.
    My self have studied sails on pontoons for many years mainly for Myark folding trailer pontoons and actually placed a patent in the early part of the design venture and had similar fold up keels like you have but where in the suspension area that replaced the wheels that also had pivoting features to allow for steering with keels.
    Another design sail I had was for flat bottom folding trailer barges which had a similar keel system just mentioned but also designed to have a rudder on the front of pontoon to give superior steering as well on the back which was also designed for the amphibious models that had a car on top for direct steering, when I was hiring out the Myark folding trailer barges to the film industry I would be following actors like Xena Princes warrior and another time Hercules in their canoes chasing bad guys and needed precision steering control especially when the wind wanted to blow the 10m X 4.8 barge side while filming with no mistake time coverage while traveling slow with out boards next to the river banks.
     

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  11. sharpii2
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    sharpii2 Senior Member

    Good luck on your project.

    You have made different design choices than I would, for the same goal, but this does not mean mine are better.

    My original idea was to have the rudder and centrboard both part of a single, longitudinal unit, so both could be easily installed or removed. (See attachment)

    This unit would bolt to the underside of the deck and the mast would install on the top. Four shrouds would hold the mast up and that would be it.

    My design makes no allowance for an awning. Yours does.

    As for the aft fairings. You probably make them free flooding, which might simplify their construction somewhat. Making them buoyant might move the center of buoyancy of the ponttoons too far aft. This could further encourage the lee bow to dig in.

    The cure for this would be to move the passengers aft, so this might not be too big of a deal.
     

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  12. pontoonsail
    Joined: Nov 2015
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    pontoonsail Junior Member

    Pontoon sailing

    The lee boards bank against a channel mounted on the sides of the boat.
    A tie rod pulls the lee boards together providing enough force to allow pivoting.
    This allows the position to be optimized during trial runs.
    The rudder is linked to the outboard linkage so steering is via the pontoon boat's wheel.
    The aft pontoon floats could be filled with flotation foam or not. This needs testing.
    The mast is still a design issue. We want it rotatable so the main can be stored on it. Bearing designs for the base and top are being finalized.
    I really like the quote-- I never learned anything from an argument I won.
    My quote is L^3 Listen Learn Lead
     
  13. OzFred
    Joined: Nov 2015
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    OzFred Senior Member

    Creating a less turbulent shape will only result in a very minor (unnoticeable) difference in performance. Consider it only if you have nothing else to spend your time and effort on.

    Getting the outboard clear of the water when sailing will help much more.

    Great effort and enjoy your vessel. :)
     
  14. upchurchmr
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    upchurchmr Senior Member

    I seriously doubt that a better (less turbulent shape) will only have a minor effect.

    Just my opinion, no proof. But I didn't see anything to support your opinion, either.
     

  15. OzFred
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    OzFred Senior Member

    There's a lot of published information on Kammback foils, where the rear part of an aerofoil shape is truncated (e.g. Airfoil Development for the Trek Speed Concept Triathlon Bicycle - PDF, 2.8mb). What this shows is that a square trailing edge is not inherently draggy and can be more efficient than a full, tapered foil (e.g. for racing pushbikes) for some applications.

    To work out if a tapered trailing edge will help this boat, the drag of the extra wetted surface needs to be weighed against any reduction in drag. The difference between the two is probably very, very small either way. So if there's a choice between that and some other enhancement, do the other. ;-)

    If additional buoyancy is required at the stern, an extension of the current tube is probably more efficient since it will provide more buoyancy for a given length than a cone, with less wetted surface.
     
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