sliding gunter

Discussion in 'Boat Design' started by wayne nicol, Sep 7, 2013.

  1. wayne nicol
    Joined: Dec 2009
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    Location: Queen Charlotte islands, B.C.

    wayne nicol Senior Member

    will a 170 sq foot sliding gunter work?
    a true sliding gunter, not a folding gunter.
    1. i have read numerous posts and reports about people being concerned about the gunter/yard jamming .
    now that has all been speculation, just wondering if there have been any real life experiences out there.
    i thought about building parrel beads into the two brackets( essentially bearings!!), to facilitate a smoother motion under load.

    it will be a carbon mast and a carbon yard.

    2. are these rigs usually laced, i also hear concerns about luff hoops jamming.
    what about rope loops (hoops)with a few parrel beads on each?

    thanks all
    wayne
     
  2. philSweet
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    Can you provide a picture of your proposed arrangement? The historical model for this rig is the Roslyn Sharpie. It works well on the right sort of hull.
     
  3. wayne nicol
    Joined: Dec 2009
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    Location: Queen Charlotte islands, B.C.

    wayne nicol Senior Member

    i currently have a 170 ft marconi on the boat, but really want to change to using shorter spars.
    so one option is the sliding gunter, probably wont even have to re cut the sail, i hope!
    but will build new carbon masts, just so that i dont have to cut the current extruded aluminum 30 ft mast.- just in case i might sell it one day.
    i plan an 18 ft mast, a 3 foot tabernacle, so the mast wil be 9' shorter, so probably a 2' overlap that makes for a 11' yard. is 2' enough?
    boom will be on the tabernacle, on a swivel/bearing mechanism- so that it can swivel forward for trailering etc.
    will try and do up a sketch.
    thanks
    wayne
     
  4. wayne nicol
    Joined: Dec 2009
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    Location: Queen Charlotte islands, B.C.

    wayne nicol Senior Member

  5. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    170 sq ft? sure, there have been larger ones. The whole reason for a gunter was to fit the largest rig into a lifeboat/whaleboat/barge.
     
  6. wayne nicol
    Joined: Dec 2009
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    Location: Queen Charlotte islands, B.C.

    wayne nicol Senior Member

    great, any ideas on my concerns- with the yard jamming etc- any idea where i might start looking, have exhausted general google search's.
    thanks-confidence building.
    now need to get some input with regards to scantlings of the carbon mast and yard

    regards
    wayne
     
  7. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Yes, the yard jams. There's also a number of other issues with this particular rig.

    No one is going to give you :

    this information, without a full set of dimensions and hydro's for the boat involved, will be all but imposable to get (without paying for the math).

    A carbon mast on a rig like this, seems self defeating to a degree. If really interested in weight reduction, lose the extra spar and rigging associated with it.

    Now of course, Eric will likely chime in with advise on the carbon aspect (carbon spars to him, are like fresh varnish to a fly), as it's certainly a possibility, but if going to all this bother and cost, efficient rig selection, just seems logical.

    Maybe it's best to define your concerns first. Why do you want shorter spars? A 200 sq. ft. main isn't a small boat (28' - 30' at least I'd say), likely not a trailerable one, so how often do you need to store these puppies? If bridges are a concern, maybe a tabernacle is a better choice.
     

  8. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    Jehardiman's reason isn't quite the whole picture, though. The rig can be set up and adjusted to provide very good gust response. If you have a smallish, lightish, shallow draftish, narrowish sailboat and you want to sail in puffy conditions, a gunter rig lets you keep some power on rather than have to reef it for the puffs. It takes less sailing effort once properly adjusted, so you can carry more sail for a given effort. It also reefs the mast with the sail, so windage is reduced when reefed. You would normally set one up to reef in quite low wind speed (unless it's a life boat). They let long skinny boats get to hull speed in modest conditions, and are manageable the rest of the time.

    It is a rig for tinkerers. I'd make the spars from wood and keep a screw driver handy. You might spend a year fiddling with it before you want to commit to a carbon stick. The mast could be carbon, but I wouldn't do the pole that way.

    You will not need to recut your existing sail - because you need to have a new one made that exploits the gunter's gust response and has the proper reinforcements and aspect ratio. Otherwise, I think the exercise is pretty pointless. We still don't know what boat you are trying to put it on. And why don't you like the folding gunter? It is a bit more straightforward.
     
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