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Thread: To broadseam or not to broadseam

  1. #1
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    Default To broadseam or not to broadseam

    I am in charge of making new sails for one of these


    When investigating old sails for these boats, I haven't found a single one with broadseams.
    The oldest sail I've found was made in 1945.
    1945 actually isn't that old, since these boats begun to use these riggs and started to be used for racing in 1867!

    But it's the closest to original that we have, and I'm supposed to stick to original as much as I can. (Within reason, noone expects me to hand-sew them for example.)

    Sailcloth is ~500 grams cotton and they are roped all around with 3/4 inch or so hemp rope.

    /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: To broadseam or not to broadseam

    As you are using natural fibre I think that the fullness is worked in when you rope the head and foot tight. Then careful stretching of the sails, in gentle breezes on their first outings moves the fullness to where you want it.
    It really is quite difficult to build an ugly wooden boat.

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  3. #3
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    Default Re: To broadseam or not to broadseam

    Well, yeah sure. But I wonder if any sailmaker of the 19th c with self esteem would make sails like that.
    I've investigated close to a hundred old sails and even the sails made by fishermen out of flour-sacks had some broadseams in them.
    Then, I will probably not be the first person sailing with the new sails, so I cannot be sure they'll be used in gentle breezes. Sure, even with broadseams, I'd prefer gentler winds and slacker sheeting, but yeah.

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

  4. #4
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    Default Re: To broadseam or not to broadseam

    There's a lotta numbers in cotton sails.
    You gotta build one shape , and finesse it into another.
    You gotta know about how much they're gonna stretch with wind and tension, and shrink with gettin wet.
    And just when you figgure you got that worked out , you gotta stitch the ropes on . They also stretch /shrink with stress and wettness...at a different rate than the cloth.
    it's deeper n a whales hole .
    and yes, there is broadseaming..

  5. #5
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    Default Re: To broadseam or not to broadseam

    Quote Originally Posted by wizbang 13 View Post
    and yes, there is broadseaming..
    Just checked my copy of Bowker and Budd. They set out how much broadseeming is required for gaff mainsails, both loose footed and not in cotton.
    On the other hand when researching "Sailing Drifters" E J March contacted several old sailmakers, all of whom talked of stretch and how to deal with it during roping, but not one of them mentioned broad seaming.
    It really is quite difficult to build an ugly wooden boat.

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  6. #6
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    Default Re: To broadseam or not to broadseam

    Quote Originally Posted by wizbang 13 View Post
    There's a lotta numbers in cotton sails.
    You gotta build one shape , and finesse it into another.
    You gotta know about how much they're gonna stretch with wind and tension, and shrink with gettin wet.
    And just when you figgure you got that worked out , you gotta stitch the ropes on . They also stretch /shrink with stress and wettness...at a different rate than the cloth.
    it's deeper n a whales hole .
    and yes, there is broadseaming..
    Not entirely sure what you are trying to say.
    To be clear: I'm in charge of the sails being made, I will not be making them. (I may end up doing the roping in the end, since I have more experience of hand-roping than anyone else involved, but that's outside of the point, really.)
    Judging from old sails, I specify the amount or round, the width of the panels, the weight of the cloth and so on.
    That's my job in this project. And I need to decide if the sails shall have broadseams.

    /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: To broadseam or not to broadseam

    All the cotton sails I have inspected were broadseamed, and till recently the sails on the SKS Skutsjes, a racing class of steel barges, were cotton and broadseamed. The saildesign was computer made and then pencilled on the cloth. Now they use dacron because good cotton canvas was hard to find they said.
    The sailmaker Willem Bosma in the Zuiderzee Museum makes sails still in cotton, and also in Clipper Canvas. I understand he often uses Sailcut 4 for designing the sails.
    Traditionally sailmakers here used a simple system to design the sail and I used it once for a square sail on a Vikingship replica. It works. If you are interested I could make a drawing to explain how it works.

  8. #8
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    Default Re: To broadseam or not to broadseam

    Quote Originally Posted by mohsart View Post
    Not entirely sure what you are trying to say.
    To be clear: I'm in charge of the sails being made, I will not be making them. (I may end up doing the roping in the end, since I have more experience of hand-roping than anyone else involved, but that's outside of the point, really.)
    Judging from old sails, I specify the amount or round, the width of the panels, the weight of the cloth and so on.
    That's my job in this project. And I need to decide if the sails shall have broadseams

    /Mats
    Perhaps the sails that you are copying were not broadseamed because the builders did not know how?
    Why would you not handstitch them , if realism is the goal?

  9. #9
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    Default Re: To broadseam or not to broadseam

    Unless the sail has a great deal of shape, it's very hard to even detect broadseaming since you're usually shifting only 1/16" over a few feet of seam. And, as I learned taking apart some panels from an old cotton sail to use for a really cool three piece suit (I was once long long ago quite spiffy) sailmakers also put in shape by cutting a curve along the panel. The three basic tools for sail shape - cut both along the panels and along luff/leach/foot, broadseaming, and roping tension - have been in use for all sorts of fabric structures from ancient tents to sails. People have been doing it for thousands of years. It sounds like you could use some professional design work from a sailmaker. This is enough work that you probably should not expect any one with a busy loft to volunteer.

  10. #10
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    Default Re: To broadseam or not to broadseam

    Yea, by cutting the curve, then stitching the seams evenly, they could "hide" their recipe !
    One cannot see broadseaming on modern computer cut sails,because the overlap is cut out, buts its there.

  11. #11
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    Default Re: To broadseam or not to broadseam

    If the BS was cut, hemming would be needed, I don't think the edges are hemmed.

    I believe that the sailmakers were not familiar with lug sails, since they are/were very uncommon here.

    I wouldn't mind hand-sewing the sails if I were to do it myself, but I don't have the time, and hireing someone who can do it would be too expensive. Also all other 9 boats have machine sewn sails.

    It's a fine line to both follow the traditional methods and design and also make as good sails as possible for racing. And still not make new sails dramatically better than the ones used when the handicap (LYS, I guess) system was set.

    I see no use of computerized design for these sails, pen and paper is plenty fast and accurate.

    /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: To broadseam or not to broadseam

    You do not hem on a sail seam. Make a felled seam.

    Most instruction on a felled seam shows something like the order below, which I find too hard to manipulate with long runs of canvass. Or even short. So at "Step 1" I actually lay the pieces back to back with the edges staggered. Once I have that exactly stapled I baste along the line that would be at the fold up if I'd positioned the pieces that way. Then I can lay the work out on a flat surface and do all the folding and rubbing to get the seam right and then run a row zig zag over each fold such that the zig goes through one layer while the zag goes through four.


  13. #13
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    Default Re: To broadseam or not to broadseam

    Do or don't, I was taught to do it like this (upper part), it makes it the same amount of layers as the false seams necessary when wider cloth is used than the wanted panel width.
    I am pretty sure that all older sails seams were sewn like this (bottom part), since the cloth came in narrower widths back then.
    Namnlös.jpg
    /Mats
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  14. #14
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    Default Re: To broadseam or not to broadseam

    I could add that the practice of putting each other stitch outside the folded material was ditched pretty much simultaneously all across Sweden, around 1920 if memory serves me right.

    /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: To broadseam or not to broadseam

    I've found a sail with BS now. It is very easy to see because of, apart from the wider seams, the (in this case) red thread near the edges of the cloth.
    That sail was made by a sailmaking company in Gothenburg in the seventies and it is quite clear that they really didn't know what they were doing.
    For example, all seams have BS at the foot and they all have the same length.

    Still, this tells me nothing about how the sails of the 19th c were designed.

    BUT, I have come across around 50 sail plans/drawings from that period. Some of them talks about BS, but not all. And the handwritten notes are not easy to decipher.
    Still, extremely interesting and exciting stuff.

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

  16. #16
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    Default Re: To broadseam or not to broadseam

    Quote Originally Posted by Ian McColgin View Post
    You do not hem on a sail seam. Make a felled seam.

    Most instruction on a felled seam shows something like the order below, which I find too hard to manipulate with long runs of canvass. Or even short. So at "Step 1" I actually lay the pieces back to back with the edges staggered. Once I have that exactly stapled I baste along the line that would be at the fold up if I'd positioned the pieces that way. Then I can lay the work out on a flat surface and do all the folding and rubbing to get the seam right and then run a row zig zag over each fold such that the zig goes through one layer while the zag goes through four.

    That is close to what my father,who was in the rag trade, would call a French seam.
    It really is quite difficult to build an ugly wooden boat.

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  17. #17
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    Default Re: To broadseam or not to broadseam

    Looking at the pic again, it kind of (but not really) looks like the way they used to sew sails in the 16th c here. That seam is called "rullsöm" (rolled seam) and is very weak, but some literature around 1900 insists that it's strong.
    Are you really supposed to sew at only one of the edges? That seems weird.

    Edit: The Swedish name is "rundsöm" which translates to "round seam".

    /Mats
    Last edited by mohsart; 05-08-2018 at 02:46 PM.
    My blog about my time as a boat building student, a rigger apprentice and Journeyman http://kaptenmohsart.blogspot.se/

  18. #18
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    Default Re: To broadseam or not to broadseam

    It's a French Feld, or Lap Feld seam. It was invented long before the zig-zag stitch and usually has two parallel lines of straight stitching which pass through all four layers. No stitching hangs off, over the sides of the folds. It is one of the strongest seams you can make in nearly any material. Sewing one with a single line of zig-zag, or these days with a single line of three-step (each zig or zag in actually made up of three straight stitches) is not as strong, but is generally adequate and is faster to produce in a production environment.

    Back in the days when I worked on hot air balloons, we sometimes had to make French Feld seams as much as 75' long, or which went around corners. Tricky ones would normally be hand folded and installed with basting tape to hold everything in place before stitching. Long straight ones would use a feeder that folded the pieces to the proper shape and seam width right before they were fed into the presser foot. Here is one of my old lap folders. It makes a balloon seam which is about 3/4" wide. This would be installed on a double needle, straight stitch sewing machine (two needles, two bobbins - essentially two complete mechanisms, side by side). The operator guides the two pieces of fabric in, keeping them under just a bit of tension. The folder then folds the lap seam and the two needles behind it sew two parallel lines of straight stitching down the folded area.

    lap-folder.jpg

  19. #19
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    Default Re: To broadseam or not to broadseam

    To be clear, the "rundsöm" I was refering to as weak looks something like this
    rundsöm.jpg
    where the straight lines are the cloths and the round symbolize the stitch.

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

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