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Re: Chinese Gaffer rig

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  • Eric
    c-rusier Thanks for the links. I did finally find a picture which made sense of the cambered sails. http://www.junkrigassociation.org/sailplans_current It
    Message 1 of 13 , Mar 27, 2011
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      c-rusier Thanks for the links. I did finally find a picture which made sense of the cambered sails. http://www.junkrigassociation.org/sailplans_current It appears that there is sailcloth at each of the lower battens cut to the shape of the desired sail camber (as if looking at an airplane wing end on) and a panel of flat cut cloth is suspended from the cloth at each batten. Like a model airplane with paper over ribs that form the shape of the wing, except for the junk sail the ribs are cloth hung from a very stiff and straight batten. Wind in the sail blows it into shape. It is not a simple nor inexpensive sail to sew, but it appears that a very effective shape can be made without otherwise harming the good traits of the junk rig. Hinged battens and sails that wrap completely around the mast fastened to hinged battens that also wrap around the mast are just too complicated and fail dangerous to be good go to sea choices. I do expect that the part of the sail that creates the shape must be of very strong sail cloth because there will be much bending of the cloth which over time will weaken it where it bends hard at the batten. It will then rip along the entire length of the batten. Traditional junk sails do not fail so catastrophically. Attention to sail fatigue will be necessary, and prophylactic repairs made well ahead of possible failure. Further reading or questioning on the Junk Rig site might result in enlightenment how the sails are actually sewn, and on the issue of sail fatigue as there are some people who have had twenty and perhaps more years experience with this sail plan.

      It still stands that the belly of the sail needs to be in the forward third and the aft part of the sail needs to be flat to let the wind flow smoothly off the aft edge (leach) of the sail.

      A comment was made about Colvin at the helm. Colvin lived aboard and sailed his junk rigged boats with out engines for decades, and he did sail those flat cut junk sails to windward. In one case sailed his fifty foot Kung Fu-tse directly to windward out of a 75 yard diameter cul-de-sac in Force 6 (25 to 30 mph) rising winds. For safety he use a method called casting with two anchors so he would be safe if he did not make a tack. His book Cruising as a way of Life is well worth the read for anyone contemplating going to sea.

      Eric



      --- In bolger@yahoogroups.com, "c.ruzer" <c.ruzer@...> wrote:
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      > Eric, I'm a beginner in this. Does western draft start in Ireland nearly as long ago as Hasler and Mcleod ideas when Dr Vincent Reddish used bricks strategically placed on top of a tarp stretched out on his thick front lawn before cutting the outline, clamping the battens, and promptly setting sail to prove it?
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      > Just think why was James Wharam so disappointed in junksails long ago? Then compare what Gary Dierking is finding now on his test bed wa'apa with a cambered junkrig: http://outriggersailingcanoes.blogspot.com/2010/10/more-junk-rig-tests.html fast sailing ability on the wind, and only early days...
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      > There's much to learn currently from the knowledgeable and helpful folks on the junkrig group - check out the file section there particularly Arne's files. The JRA site is recently updated - check out the public pages resource there.
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      > http://groups.yahoo.com/group/junkrig/?yguid=140880010
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      > http://www.junkrigassociation.org/
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      > --- In bolger@yahoogroups.com, "Eric" <eric14850@> wrote:
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      > > c.ruzer,
      > > What is the source of your information about modern junk sail plans having draft built into them. I know Colvin calls for flat junk sails with no draft. And my memory is that Hastler and Mc*****'s book on the modern junk rig also calls for flat sewn sails. Their insight being to not have so much sail forward of the mast as traditional junk rigs and a few other details. Until ten years or so ago these authors were the go to authorities on the modern junk rig.
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      > > Eric
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