how to determine sail area

Discussion in 'Boat Design' started by stonedpirate, Feb 13, 2012.

  1. stonedpirate
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    stonedpirate Senior Member

    So you are saying that epirbs are useless for circumnavigations and no one should carry one once they leave their local waters?
     
  2. Yobarnacle
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    Yobarnacle Senior Member holding true course

    Satelite imarsat epirbs will let folks know you are in distress and where. The problem is, in many parts of the world, there are no SAR (search and rescue) organizations available to come get you.
    There is still the chance private vessels or military transiting near you, can be diverted to assist.
    Epirb increases chance of but does not guarantee rescue.
     
  3. stonedpirate
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    stonedpirate Senior Member

    I realise that, i'll take one anyway with no shame or guilt just like all the other recreational sailors putting their lives at risk.
     
  4. FAST FRED
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    FAST FRED Senior Member

    I still think a heavily constructed sit on top kayak with soft top shelter and kite power is a good idea for long distance coastal cruising, just not at 8 feet.

    A 14 footer could be less fat, faster etc.

    Some people have no imagination


    Imagine being 15 ft underwater and wondering IF you can hold your breath for the time it takes to reach the surface!

    FF
     
  5. stonedpirate
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    stonedpirate Senior Member

    thats actually a good point and surprised nobody mentioned it :p

    kite chair is dead
     
  6. GTO
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    GTO Senior Member

    Why don't you try to build a Yankee Girl II?

    About as "proven" a design you could find and would save a lot of time and effort.
    If you are serious about setting the record, you need to beat Yrvind to the launch so time is of the essence. He might beat your record shortly, but at least your name would make the list.
     
  7. stonedpirate
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    stonedpirate Senior Member

    His boat is 10'

    Mine will have to be 9 and a half.

    Even if i left today on a 10 footer, there is no way i can beat him on his non stop southern route. Trade winds will take years. He is aiming for under a year.

    Thats if his route is even considered a circumnavigation.

    I will give him the record for smallest non stop great capes circumnavigation, but i still think it needs to be beaten with a true circumnavigation.
     
  8. stonedpirate
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    stonedpirate Senior Member

    On top of that, he is only giving himself a 50% chance of survival.

    At his age, anything can happen.

    He needs to cross the line first.
     
  9. padilac
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    padilac Junior Member

    kite sailing kayak

    Hi.
    Just read an article (in the norwegian magazine Padling) about taking a surfkite to a sit on top kayak. The tester is relatively experienced in kite surfing on water and snow, as well as beeing well used to kayaks.
    He found that launching was difficult, speed and manouverability was abysmal compared to his surfboards. He claimed this was due to hull shape and less ability to use hips and legs in the kayak. He also found that side drift took a fair bit of usability out of the idea. This was of course a regular kayak without a keel or daggerboard.

    The main showstopper was the great difficulty in relaunching the kite, and a low performance against the wind. how much of this could be negated with a better sailing hull I dont know, but tacking becomes much more exiting if your entire rig can dive in the ocean..
     
  10. sharpii2
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    sharpii2 Senior Member

    Even a surfboard has a keel of sorts (a skeg).

    I suppose a surfkite doesn't need a keel or board, because, when it's sailing upwind, it's tilted at such an angle to the surface it acts like a long keel itself. As I have said in other posts, long keels work more like angled plows than airplane wings. And that's exactly how the board of a surfkite works.

    The difficulty of the kite crashing into the sea could be ameliorated to some extent by inflating it with a lighter than air gas, such as helium or even hydrogen, to keep it aloft in even the lightest breezes. But then, if the line parts, there is no hope of retrieving it.

    The concept of a kite powered boat, for crossing vast stretches of open water, has some definite merits, but may never prove as practical as a more conventional sailboat.

    But I'm willing to keep an open mind about it.

    It is also conceivable to use a kite as a light air sail in conjunction with a stubbier conventional rig.

    If the kite is lost, there is still the working rig left behind.

    The kite could be smaller too and could be hauled in and stowed when bad weather threatens.
     
    Last edited: Feb 25, 2012
  11. padilac
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    padilac Junior Member

    yes, its an interresting idea

    A kite sail is obviusly possible. But probably not a good main rig for a vessel of this thread.
    If you look up dirigibles, you will find that they are sensitive to cooling by rain, and need frequent adjustment. by wetting a party ballon filled with hydrogen, you will see that it has difficulty taking off from the surface again. I do not think a regular kite has enough volume in its inflatable ribs to fly. Hydrogen also escapes through most materials, so making a kite to preserve its gasreservoirs and have enough bouyant volume will likely be something of a specialized affair.

    As to surfboard skegs, I am aware of this, and if memory serves the kayak testet had a rudder. But of course the surface area is too little to lend much in the way of sideway support against a large sail. Training kites are faily cheap however, so it is reasonably easy to experiment.
     
  12. sharpii2
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    sharpii2 Senior Member

    The skeg would not have worked no matter how large it was. It was too far aft of the kite line.
     
  13. padilac
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    padilac Junior Member

    Ok, I admit I have very little experience in sailing. But a sail from a ballon? How would that be controlled? I see the downwind capacity, but how about against the wind? wouldent this be a very limited system for overall performance? Bearing in mind that Lighter Than Air aircrafts has been around for centuries, I cant but help thinking that someone has tried and (in embarresment) abandoned this before. As to onboard Hydrogenmaking I would be very sceptical of the fire hazard. Few things scarier than fire in a small vessel.
     
  14. sharpii2
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    sharpii2 Senior Member

    All very good points.

    Saying an idea is conceivable is not saying it is good.
     

  15. stonedpirate
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    stonedpirate Senior Member

    Who is talking about a balloon?

    Inflatable kites have air inside the leading edge and frame so the float on the oceans surface to make them easier to launch from the water and to maintain aerofoil structure.

    Kite surfers have no problem launching their inflatable kites from the water after a crash.

    And kite sailing vessels will be part of the future of sailing.

    [​IMG]
     
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