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  1. #16
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    Quote Originally Posted by keyhavenpotter View Post
    Although I have been reading about sail making - as usual struggling to get the concepts into my head. It's just amazing how seeing a sail made on video makes understanding so much easier. Here are sail making videos on YouTube. Not sure what the wife is going to say about sticking "picks" in the lounge floor!

    http://uk.youtube.com/results?search...&search=Search

    Brian
    Brian,
    Nice find, that is a really good set of instructional vids and well done to the bloke who put them together.

    Hmm....our lounge floor is slate I wonder if SWMBO would mind a few sheets of particle board for a while. Of course I'd give them a coat of varnish so it looked good. We have a split level so I can have simulated sewing machine pit

    Mike

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  3. #17
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    'Delaide, Australia
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    Why simulate when you can borrow a chainsaw. Then you can cover the hole with one of those bits of particleboard.

    MIK

  4. #18
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    Sep 2008
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    germany
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    Quote Originally Posted by Boatmik View Post
    Yep,

    I would agree with that completely. I can do the simple edge shaped sail design, but someone else will have to work out the multipanel seam shaped (broadseamed) patterns using a program as you describe. I can give you the parameters for fullness and twist if you want to have a fool around with the program.

    Michael
    Hi,

    I played a bit with sailcut. Mik, what are the parameters for fullness and twist ( and how is the matching stiffness of yard and boom)?

    Greetings - Jörn

  5. #19
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    Howdy,

    I would tend to be quite conservative for a first sail. Underestimate both the depth and twist of the sail.

    I would choose a fullness around 10 percent for a first sail. Better a little bit too flat than too full.

    Twist I would expect around 10 degrees.

    Draft about 40% back or a little under that. I think that is the general range for headsails ... and this will be at the front of the boat like a headsail.

    Yard and boom bend .. about 30mm. For the yard it is centred halfway along. For the boom about 1/3 back from the front end.

  6. #20
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    May 2008
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    UK
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    Hi

    have put approximate dimensions for RAID41 mainsail into Sailcut CAD, with your figures from above post. When you rotate the sail horizontally and vertically it looks quite nice. The programme allows fullness at three points up the sail, so I entered 10% for the foot, 7% mid point and 6% top section.

    Guessed gaff angle at 20 degrees, looks about right, and sheeting angle for a lug main with no jib as 15 degrees?

    Seems to only export to more complex ,dxf files etc and not .jpg so I could post here.

    I really like the revolving feature that lets you see the shape of the sail from all angles. Broad seaming does not look so intimidating after watching the sailmaking videos.

    Brian

  7. #21
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    Quote Originally Posted by keyhavenpotter View Post
    Hi

    have put approximate dimensions for RAID41 mainsail into Sailcut CAD, with your figures from above post. When you rotate the sail horizontally and vertically it looks quite nice. The programme allows fullness at three points up the sail, so I entered 10% for the foot, 7% mid point and 6% top section.

    Guessed gaff angle at 20 degrees, looks about right, and sheeting angle for a lug main with no jib as 15 degrees?

    Seems to only export to more complex ,dxf files etc and not .jpg so I could post here.

    I really like the revolving feature that lets you see the shape of the sail from all angles. Broad seaming does not look so intimidating after watching the sailmaking videos.

    Brian
    Sheeting angle for the front sail of most boats is 10 degrees. Slower boats can go a bit wider ... maybe 12deg.

    Sounds too flat in the top but that might be all that is possible with the amount of twist. If you can squeeze a bit more fullness in then that would be nice. If you are setting up with the vanging systems you have been using on your boats then maybe can come down to 8 degrees twist ... though for people who are not going to be working quite as hard in getting sails trimmed right then the flatter in the head option will be more forgiving.

    I can check the "gaff" angle in the morning .. after midnight here.

    You can email DXF files to me and I can convert them and put them up for you. Other way is if you can convert documents to PDF fles you can copy and paste in to a graphics program and save as a jpg.

    MIK

  8. #22
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    Have now worked up a sail design for a four sided lug sail and the triangular mizzen using Sailcut4. Having chosen fullness, twist, panel layout etc it is then very quick to create a sail with different dimensions using the same fullness etc. A version of my Scow sail only took a few minutes. One for the Goat, if given the dimensions would also only take a few minutes.

    My local supplier of remnant sailcloth turned up trumps. Enough 4 oz Dacron to make two sets of Raid sails was only £53 - £26.50 per set must be as cheap as Polytarp?

    When I began this process I wondered about avoiding sewing. Boat builders are used to glues, fitting curved panels but not sewing. Could I find a glue for Dacron? Well, yesterday I came across this interesting piece about the strength of glued seams on dacron being stronger than sewn seams.

    http://www.cruisingworld.com/how-to/...ue-201615.html

    The product is 3M 5200 FC and can be obtained in small dispensers at around £6 cost.

    http://solutions.3m.co.uk/3MContentR...ersion=current

    The concept would be to use a double sided 1/4" tape in a 3/4" seam, build the sail - only 4 seams in my panel layout - check out the set then apply the glue to the open seams.

    Anybody tried this??? Just think glued seams might be more popular with builders rather than sewn seams. Keeping control of the glue will be the main issue.

    Brian

  9. #23
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    Howdy Brian,

    It is a big and interesting area.

    The PDR people do use hardware materials to tape some of their sails together.

    Also many of the highest tech sails are taped together too with no stitching.

    There are a few different grades of double sided tape ranging from ones that are used to hold the sail together temporarily through to ones that will hold it together permanently.

    My sailmaker (when I was doing the PDRacer research) said that the best grade of tape (expensive) works well with sails made of laminated cloth (ie non woven film - mylar - by alternating the panels you can usually make sure that you are bonding the film side of one panel to the film side of the next at the seam) but the cheaper tapes are not terribly reliable, particularly in Australia's hotter climate.

    He said he only trusts the best tape and only trusts it on laminated cloths where it can bond to the mylar side.

    He did not mention the 5200 - I think the convenience of the tape was a big factor for a commercial loft.

    Michael

  10. #24
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    Hi MIK

    thinking along the lines of using a cheaper tape as an aid to assembly and then glueing with a bead of 3m 5200. I think the stronger tape is sold by Sailrite as Super Seam-Stick. Have not found that in the UK yet.

    Tod Bradshaw kindly posted these comments on the WB forum.

    "Dimension Polyant Sailcloth has been selling an air-powered hot glue gun to use in conjunction with a basting line of 1/4" tape, instead of stitching, for quite some time. You baste one side of the seam with the seam tape, stick the nozzle of the gun under the flap, shoot a bead of glue in there and roll it down. Drawbacks are the cost of the gun ($2K) and that you need to do a lot of seams at once, because once opened, the glue cartridges have a fairly limited "pot life". If you could control the excess and had space for it to dry flat, 5200 might do the same job just about as well..."Honey, do you mind if I spread this sail out on the living room carpet for a little while?"......"

    Brian

  11. #25
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    Sounds pretty much like what we do with the PDR sails .. dry assemble with the cheaper tape .. then we stitch.

    There will probably be a requirement for the amount of bonded seam width relative to the sailcloth strength/weight.

    MIK

  12. #26
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    Been struggling with my back but thought I would try laying out the panels on my sailcloth last Sunday.

    Managed to clear enough room in the lounge, really surprised just how long the leach is when it's laid out in front of you in the flesh. 16' sees huge laying there.

    Since I cannot spike the cloth to the lounge floor, tried parcel tape, learned I need to use far more to hold it steady whilst I worked on the dimensions.

    After 15 minutes my back went and am now in twice the pain - stupid or what!

    My cloth is actually 1500mm wide and I had planned on 700mm panels to keep it looking nice. Those seams look so long though. Wondered about simplifying the layout and using the cloth at 1500mm. This gives only two vertical panels, and thus only one joining seam. It suits the PDR/RAID41 simplify ideas, and also MIK has remarked about the Laser being a flat sail. The Laser does have mast bend though.

    I have tried a layout in Sailcut4 and it looks nice enough in the drawing, the question is - could it work in the flesh? It would be great if it did - there is only one seam to sew/glue, so much easier to make and less to split. Presumably the shape would not be as good as a 4 panel sail, but would it be good enough? Hope so.

  13. #27
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    MIKs lugs have flexible boom & gaff to do the same job as the Laser's flexible mast.
    As he seems to have designed these spars around a flat-cut sail, I wonder if they
    would need re-sizing around a shaped sail ?
    cheers
    AJ

  14. #28
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    Howdy Brian,
    It depends on what you are shooting for. If you are following your idea of the ultimate sail .. the narrower panels are better. But it would be possible to get a reasonable pair of sails with a simpler layout though a bit of performance would be lost.

    One thing though .. this boat will be shown off a bit in the UK ... so depends on your "marketing" angle. Is it a cheap homebuild with polytarp sails or something that will make box boats appeal to the mainstream?

    Michael

  15. #29
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    Just trying to shoot for a low cost nice dacron sail to go with the low cost polytarp already available. Seemed a nice thing to have for a nice boat that's all.

    the vertical cut means the leach panel is 16' long plus room to work around brings it up to needing a 20' plus flat floor to cut the panel out. Too long.

    Re-laying the sail out to a horizontal cut, with 750mm panels ( my cloth is 1500) makes the maximum panel length only 9'. much easier to handle, although there are now seven panels. I will check later but I think the 750mm panels size puts the first two panel seams in the right place for fitting horizontal battens into the seam. This also sets the place then for the two reefs for the sail.

    Then tried cutting down the number panels by specifying 1250mm cloth. This cuts it down to just 4 panels. Also falttened the head and slightly flattened the mid section. Very confused now, help and guidance much appreciated.

    The actual panels curves are minimised also as you can see here in the pdf output. Perhaps this is the way to go?

    Brian

  16. #30
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    Howdy Brian,

    I would always go for the minimum number of panels except for a raceboat. As you are club racing I would suggest going for the best performance option.

    It will be easy enough for me to draw up some basic edge shaping only sails that could be made of polytarp or out of dacron. This will cover the simple option.

    But the gap is for a nice sail I guess.

    Michael

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