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Thread: Roping detail: Rat's tail

  1. #1
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    Default Roping detail: Rat's tail

    It seems I am starting to get a hang on this moment now; I am not an expert, but I decided to document the process I use.
    Todd and others are welcome to point out if I am doing somthing wrong; this is nothing I've been taught or read how to do, just learned by thinking and doing. :-)

    I start with a simple whipping to mark where to start and to hold the rest of the rope together.


    I then open up one strand and thin out the threads.
    For thicker lines (or synthetics) I'd scrape with a dull knife, but this is 8 mm hemp so I simply use a comb.


    Then I wax the finished strand.


    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  2. #2
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    Default Re: Roping detail: Rat's tail

    I twist and wax the strand againn, then i tie it up so it won't be in the way when I work with the rest.


    Then I put back the strands; I start with two and after an inch or so I put in the third strand. Then I secure the work done so far with a thread. Then another inch and a new knot with the thread. And so on.


    I leave the thread on until I've finished roping, so that I wont deform the rat's tail during that process.


    And that's that.

    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  3. #3
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    Default Re: Roping detail: Rat's tail

    very good!
    ive often wondered how this is done.
    thanks for posting.

  4. #4
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    Default Re: Roping detail: Rat's tail

    Looks good to me too.
    It really is quite difficult to build an ugly wooden boat.

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  5. #5
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    Default Re: Roping detail: Rat's tail

    That's pretty similar to the method I use, though for the small sails I usually build the rope is only 3/16" diameter. As long as you maintain (or renew) the twist as you work with the strands, everything seems to fall together pretty well.

    http://www.frayedknotarts.com/tutorials/rattail.html

  6. #6
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    Default Re: Roping detail: Rat's tail

    Thanks guys!

    I should add that if I scrape the yarns with a knife, I finish by going over them with a couple of strokes with a steel brush to take away any unevenness left.
    This is taken directly from how I prepare the leftover strands for "worming" (not sure the term applies in this context) an eye splice before parcelling and serving.

    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  7. #7
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    Default Re: Roping detail: Rat's tail

    And sewn into place. I seem to always get a bit of deformation near the tip of the tail, but my experience is that it will work itself out after some use.
    At the tip of the tail I go around the whole thing because I cant rope that bit "properly" without messing it up.

    20180709_181253_s.jpg

    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  8. #8
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    Default Re: Roping detail: Rat's tail

    Awfully sharp radius on that corner. What size is the ring that goes there?

  9. #9
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    Default Re: Roping detail: Rat's tail

    Oh, is that a problem?
    I would think the ring will be something like this
    20180709_181253_s_ring.jpg

    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  10. #10
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    Default Re: Roping detail: Rat's tail

    It depends on exactly what part of what size sail it is, but just eyeballing it a ring that size looks kind of small for that corner. Usually you want the corner's radius to sort of nicely mirror the ring's shape with a pretty uniform margin around it.

    corner-detail-3.jpg

  11. #11
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    Default Re: Roping detail: Rat's tail

    It's the downhaul corner of a lug topsail, a little bit larger than one square meter, 1.2-1.3 perhaps. Light wind sail.
    I could do it like your first example if that would be better.

    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  12. #12
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    Default Re: Roping detail: Rat's tail

    Would it be too much to ask for a reply, Todd?

    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  13. #13
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    Default Re: Roping detail: Rat's tail

    To do a cringle that would look OK you would definitely need a bigger corner radius, both to hold the anchor rings or grommets (minimum of two) and so that the rope can curve the opposite direction to form around the inside edge of the thimble. I think your best bet is either to stick with a really small ring that will echo the corner radius, and which should be strong enough on such a small sail, or go with a bigger ring which has been set farther inboard. The margin around it will be uneven and look a little odd, but structurally it would be fine.

    Get in the habit of making a light pencil tracing around the proposed corner hardware before you cut the corner itself to shape, making sure the two shapes go together nicely - and well before doing any roping there. In some cases where the sail is attached to a gooseneck, mast or boom, you may also have very specific amounts of tack setback to deal with, depending upon exactly where the tack fitting on the spars is located and whether the boltrope goes into the mast groove or might have hoops, slugs or slides. There is no faster way to screw up the set of the sail than to get the tack setback wrong and distort an entire section of it. Corner planning and potential selection of the hardware should be done quite early in the design phase and mentally noted before the first stitch is made. It just helps to eliminate unpleasant surprises (and having to fix them) later.

  14. #14
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    Default Re: Roping detail: Rat's tail

    Thank's Todd, would you be kind enough to explain why a sharp corner is bad?
    I have seen staysails or jibs with much sharper corners that seems to have had worked fine.

    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  15. #15
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    Default Re: Roping detail: Rat's tail

    !superb

  16. #16
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    Default Re: Roping detail: Rat's tail

    With rings and grommets it's as much about aesthetics as anything else. The strain in use on a corner ring is concentrated on the side of the ring closest to the middle of the sail, so whether the corner behind it is sharp or more rounded isn't going to matter much structurally. A pleasing visual transition from the hardware to the cloth which looks like they belong together simply looks a lot better. It's one of those "elements of craftsmanship" things - taking the time to get things right, even though they may not be critical. Sadly, the number of sailmakers or production sail loft assemblers who still care about such stuff (or even know of the concepts) gets smaller every year.

    For a cringle, it would be a different story. I don't think you could get the proper anchor rings into such a sharp corner, or get the sharp corner's roping to wrap properly around the inside edge of the thimble without making a big distortion in the fabric at the corner. A cringle's thimble should be such a tight fit into the roping surrounding it that you can barely get it to spin, if at all. I can't see such a sharp roped corner producing that scenario or a smooth corner.

  17. #17
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    Default Re: Roping detail: Rat's tail

    Thanks, all clear now.

    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

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