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Thread: Joining rope end to end to make mast robands

  1. #1
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    Default Joining rope end to end to make mast robands

    I sail a small, 13' Cats Paw dinghy with tapered spruce mast . I had been lashing my sail to my mast with a continuous piece of rope. Often the results were less than perfect with bunching and crinkling of the sail. I've decided to use rope robands combined with a attaching the sail at top and bottom, ie, downhall rather. I will also make removing and reattaching the sail to the mast much less time consuming.
    Here's a quick and easy way to join a piece of rope end to end to make a roband. What I like about this method is it is very easy to achieve a precise diameter since the rope is joined end to end. It's also makes for a neat, tidy, and strong joint. I cannot pull this apart (keep in mind I'm 62) It's also a quick method which is nice since multiple bands are needed.

    The mast is about 1" diameter at the top and 3" diameter at the bottom. I measured and recorded the mast diameter at all the points where the sail eyelets line up. My target roband diameter is ~ 15% greater than the mast diameter at those points. This an image of the lowest one where the mast is 3" in diameter. This roband is 3.5" in diameter. I've pictured this one not attached to the sail for clarity. Of course one needs to thread the rope through the sail grommets beforehand.

    1. For the first band, cut a piece of rope to length according to the recorded measurements plus 15%. I used 3/16" diameter rope since my mast gets quite small toward the top end. I use a very sharp knife against a cutting board. I find this leaves the least amount of fraying which is important when getting the rope into the shrink tube.
    2. Cut pieces of shrink tubing about 1/2" long. The diameter of the shrink tubing i used is 1/4", 1/16" larger than the rope.
    3. Slide the shrink tube over on one end completely, leaving the rope end exposed, ensuring all the strands are contained. Then, slide the shrink tubing back so that the end of the rope ends in the middle of the shrink tube length.
    4. Apply a big drop of super glue gel into the cup formed by the shrink tube/rope. Wet the other end of the rope with super glue gel also but be careful not to fray it.
    5. Press the newly wet end into the cup with some pressure ensuring all the strands are contained. Hold for 20 seconds then apply heat to shrink the tubing.
    6. Repeat for all successive bands, cutting the rope pieces to the corresponding lengths. It's best to do the cutting right before the piece is needed rather than all at once to reduce the possibility to fray.

    A strong glue joint needs a lot of surface area. I assume the supper glue gel leaches up the rope and contacts the heat shrink tubing along its' full length/diameter, and this accounts in large part for the strength of the joint.


    0713190655.jpg

  2. #2
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    Default Re: Joining rope end to end to make mast robands

    Interesting approach. The traditional way to make robands was to fashion quoits from three strand line: https://www.instructables.com/id/Rope-Rings/

  3. #3
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    Default Re: Joining rope end to end to make mast robands

    Good method/link. Funny I googled rope robands and that did not come up. Perhaps "Rope Rings" would have brought that up. Indeed that may be the better way but looks like it takes more effort. On the other hand, I'm not sure super glue holds up to the weather. Hopefully the shrink tubing keeps the water away from the glue. Perhaps a second piece of the same shrink tubing albeit longer over the first would be better. BTW somebody sells shrink tubing with a layer of hot glue on the interior - easier.
    I haven't done this to my sail yet. I'll post after I try it out on the water.

  4. #4
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    Default Re: Joining rope end to end to make mast robands

    Why not use three strand ? It's not hard to make rope grommets, once you know the sizing it's quick.

    Cheers,
    Mark

  5. #5
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    Default Re: Joining rope end to end to make mast robands

    Neat idea. I did this a bit differently for an iceboat gaff rig where I needed to take the sail off and on the mast in cold weather. Using sailmakers lace line ( about 1/8") I made up a set of robands with a toggle on one end and a eye seized to the other. Each is cowhitched to a grommet in the luff. They are long enough so that they go on the diagonal in the usual Z pattern with each roband toggled to the next. That way they grow in length when the sail is down just like back and forth lacing. A bit of experimentation with length was needed. The main point: operated with thin glove liners in below freezing weather.
    Ben Fuller
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  6. #6
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    Default Re: Joining rope end to end to make mast robands

    Quote Originally Posted by Ben Fuller View Post
    Neat idea. I did this a bit differently for an iceboat gaff rig where I needed to take the sail off and on the mast in cold weather. Using sailmakers lace line ( about 1/8") I made up a set of robands with a toggle on one end and a eye seized to the other. Each is cowhitched to a grommet in the luff. They are long enough so that they go on the diagonal in the usual Z pattern with each roband toggled to the next. That way they grow in length when the sail is down just like back and forth lacing. A bit of experimentation with length was needed. The main point: operated with thin glove liners in below freezing weather.
    That pop you heard was my head exploding. Now, where did I put all that small stuff and those persimmon chunks?

    Peace,
    Owns Spritsails

  7. #7
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    Default

    When lacing a luff to a mast it's best to go back and forth rather than making a spiral. Then it won't bunch up. Harder to explain than to do. Bring the rope end around the mast, through the eye, then between the luff rope and the mast and back the way it came, around the mast and through the next eye from the other side, then back the way it came, kind of a zig zag.

    Sent from my CPH1851 using Tapatalk

  8. #8
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    Default Re: Joining rope end to end to make mast robands

    One inch diameter at the truck and three inches at the partner .. and yer makin special "robbands"?
    What color are the gaff span shackles?
    I mean how many are there ... 3?
    How does the one inch robband plus 15 percent do when it comes down to the three inch part of the mast?

  9. #9
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    Default Re: Joining rope end to end to make mast robands

    Actually the formula for the length of the piece of rope for a given mast diameter should go as follows:
    pi x diameter plus k, where k is arrived at by estimating how much space is required between sail and mast such that the sail just clears the mast. Indeed the percentage doesn't work out at the smaller end of the mast as you implied wizbang13.
    The boat is sprit rigged, ie, sprit at top, no boom, one simply ties off the sheet aft. There are nine grommets spaced about one foot apart to attach the trapezoidal sail to mast.
    Since the mast is a basically a linear taper. the robands/sail can be slid on and off starting/finishing at the 1" end of the mast.
    I just couldn't get my head around estimating the correct length for three strand. This alternate method is also very quick to produce.

  10. #10
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    Default Re: Joining rope end to end to make mast robands

    Total hack job. Get yourself a copy of the Rigger's Apprentice by Brion Toss and invest an afternoon into learning how to make grommets from three strand line.

  11. #11
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    Default Re: Joining rope end to end to make mast robands

    ^ this is the answer although I would suggest Ashley
    (The size of the grommet will be limited by the number of tucks in the first loop)

    For robands to work well, the mast needs to have one straight edge facing forward.
    The rest of the column can be curved as normal.

  12. #12
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    Default Re: Joining rope end to end to make mast robands

    My understanding of the roband is that it's easily opened, maybe with a toggle, maybe with a simple square/reef knot. A fixed loop would be a grommet. A roband tied off with a square knot is most handy because you can adjust the size infinitely. It's also a very quick job to remove the sail from the spar.
    -Dave

  13. #13
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    Default Re: Joining rope end to end to make mast robands

    I will pass along an idea that I'm currently working on. The gaff rigged sail on my Barnegat Bay Sneakbox is attached to the mast with five mast rings. The mast is almost 5 inches in diameter at the bottom. I was using rigid mast hoops.

    I tried that but quickly ran into problems. When I step the mast, I'm doing it by myself. So I have the rather unwieldy 20 ft mast, with the three stays attached up top, and some of the rigging trailing along too. I have to fit the mast into the five mast hoops (already attached to the luff of the sail), and then down into the hole in the deck. Its pretty hard to do and keep all the rigging straight.

    So, it would be nice to have a detachable mast hoop/roband. Leave the roband lashed to the sail, but have a quick disconnect method so I could attache the sail after the mast was up and in place.

    I was thinking of nylon webbing, maybe 1/2 inch wide. A quick buckle would be nice. And maybe a "D" ring in the webbing as a lashing point to the sail.

    I was thinking of sewing up this kind of thing, when I realized that EXACTLY that kind of thing is readily available..... a dog collar. So I bought 5 dog collars..... adjustable 10 - 14 inches, for $1 each. I have already lashed them to the sail. The nylon webbing slides up and down the mast very easily. I'll be testing this tomorrow.

    I'll let you know if / how this works.

  14. #14
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    Default Re: Joining rope end to end to make mast robands

    Creationists aren't mad - they're possessed of demons.

  15. #15
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    Default Re: Joining rope end to end to make mast robands

    I have done them with small three strand stuff. An eye spliced in each end, one end with a toggle or button in it.
    Eventually as I got older and time was moving faster I went with bandsawn slices of white PVC pipe, used a round over bit in the drill-press on the ID, siezed them to the sail grommets and called them "Whalebone hoops", very traditional

  16. #16
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    Default Re: Joining rope end to end to make mast robands

    making SOFT SHACKLES is easily learned

    a slip noose w/ a dog knot on the other end

    th-4.jpeg th-1.jpeg



    using hollow braid rope they can be made in any desired loop size and from any diameter braid you wish

    the Jeep/4wd guys are replacing the metal shackle for recovery gear w/ Dynema soft shackles

    the hammockers are using soft shackles to connect the suspension components for their hammocks

    commercially made 7/16" Dynema soft shackles offer 30,000#+ strength for the off roaders

    using 7/64"(what hammockers use) Dynema hollow braid would be way plenty strong and quite light in weight aloft

    here's a step by step tutorial

    https://www.animatedknots.com/soft-shackle

    once you learn how to run the simple splice( remember spicing ski rope ? ) and make the knot all you will need to do is decide what size loop to make

    easy peasy

    sw
    "we are the people, our parents warned us about" (jb)

    steve

  17. #17
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    Default Re: Joining rope end to end to make mast robands

    So many ways. This hacker got it done and it works well for me. I really doubt I could twist three strand together and get the diameter correct 10 times without dedicating a full day of failure.
    Sounds like there's a need for a small footprint, end to end, releasable fastener for rope.

  18. #18
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    Default Re: Joining rope end to end to make mast robands

    Ian Farrier started using plastic buckles and nylon strap to hank the jib onto his F-22 trimaran and reported it worked well. You trust them on your life jacket, right?
    -Dave

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    Default Re: Joining rope end to end to make mast robands

    Quote Originally Posted by Jim Pitman View Post
    Sounds like there's a need for a small footprint, end to end, releasable fastener for rope.
    Those are called knots and splices.

  20. #20
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    Default Re: Joining rope end to end to make mast robands

    Quote Originally Posted by Jim Pitman View Post
    Sounds like there's a need for a small footprint, end to end, releasable fastener for rope.
    Those are called knots and splices.


    Quote Originally Posted by Jim Pitman View Post
    I really doubt I could twist three strand together and get the diameter correct 10 times without dedicating a full day of failure.
    Half an hour, tops. Easier than it sounds with the right explanation to follow.

  21. #21
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    Default Re: Joining rope end to end to make mast robands

    It's really easy with the dog collar:
    20190715_154152.jpg
    20190715_153206.jpg

  22. #22
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    Default Re: Joining rope end to end to make mast robands

    You know those plastic clips slip or crack with too much force on them right? I've never had a belt with one on stay latched all day.
    2019: returning from being sidelined with medical probs, crossing fingers worst is over, still in "armchair enthusiast" mode for time being.

  23. #23
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    Default Re: Joining rope end to end to make mast robands

    Quote Originally Posted by RichW View Post
    It's really easy with the dog collar:
    20190715_154152.jpg
    20190715_153206.jpg
    Wow, that is ugly.
    I use soft shackles made of 3-strand, an eye splice in one end and a wall and crown knot in the other.

    /Mats

    Elected Swedish Yourneyman of the Year 2019

  24. #24
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    Default Re: Joining rope end to end to make mast robands

    A dog collar, a bit of binder twine and a zinc plated ring, walk into a bar ...... that suddenly had a 5 meter swell and a 35knot nor-easter...... And the barman said, 'what was that snap'?

    Superglued rope? Have you given it a good ol tug? What kind of weight do you think it'd take?
    It's all fun and games until Darth Vader comes.

  25. #25
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    Default Re: Joining rope end to end to make mast robands

    Wow, this thread is brutal....
    Simmons Sea Skiff build photos here:
    https://photos.google.com/share/AF1Q...92a21VWm02bmhR

  26. #26
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    Default Re: Joining rope end to end to make mast robands

    You are a bunch of salty old dogs.

    My input: super glue gel, or very thick CA, has very poor wicking properties. It is designed to stay put on vertical or overhead pieces.

    When CA dries is has no flexibility. It will add a stress point on the robands. If the glue/heatshrink doesn't fail, the line will at the point the glue stops.

    It is also listed as waterproof, but in my experience, when dried CA is subjected to immersion, it becomes quite brittle. The thin CA's I use quite often in model aircraft would actually begin to crystallize and fall apart on their own.

    Considering I have never seen it used in boat building, I am hesitant to say I am the only one who has noticed this.

  27. #27
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    Default Re: Joining rope end to end to make mast robands

    I hear you, I've spilled a drop or two of CA on my pants in years past. What happens after that is the spot cracks up with repeated wear and washings and you end up with a hole. That's just on a pair of pants not something under tension.
    2019: returning from being sidelined with medical probs, crossing fingers worst is over, still in "armchair enthusiast" mode for time being.

  28. #28
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    Default Re: Joining rope end to end to make mast robands

    Just to give you skeptics an update on the dog collar mast hoops.....

    I went out today with five of the collars in place of traditional hoops. The collars are plenty strong enough. I'm not planning on being out in 35 knots or 5 foot swells, so the strength of the nylon webbing and the plastic snaps is plenty for what I need. The collars are MUCH easier when stepping the mast:

    1. Mast goes up and in.
    2. assemble and clip in the stays,
    3. attach boom & gaff.
    4. snap the five collars around the mast.
    Done.

    And I'm much more of a function over form kind of guy. If I wanted "form", I would have opted for the plaid dog collars.

  29. #29
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    Default Re: Joining rope end to end to make mast robands

    If I ever find a faster to make and/or faster to assemble than the soft schackle made of a 3-strand, I'll probaby swich to it, but that is unlikely to happen.

    /Mats

    Elected Swedish Yourneyman of the Year 2019

  30. #30
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    Default Re: Joining rope end to end to make mast robands

    Also note that the patent protection for the original (and very high quality) Fastex buckles ran out quite a while ago. These days, the knock-offs can be (and very often are) made from much cheaper and drastically weaker types of plastic. There is a reason why the good buckles can cost considerably more. If it's holding something important, let the buyer beware.

    It looks to me like the boltrope on that sail is shrinking with age. In-use symptoms would be excessive sail draft and an inability to flatten some of that draft out with halyard or sheet tension when desired. It's not awful yet, but is something to keep an eye on, which can be fixed if ever needed.

  31. #31
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    Default Re: Joining rope end to end to make mast robands

    Quote Originally Posted by Todd Bradshaw View Post
    .

    It looks to me like the boltrope on that sail is shrinking with age. In-use symptoms would be excessive sail draft and an inability to flatten some of that draft out with halyard or sheet tension when desired. It's not awful yet, but is something to keep an eye on, which can be fixed if ever needed.
    Thanks Todd. I'm new to the sailing terminology, but I think I understand. Repeat, please so I definitely understand??
    The sail was used and I got it for nothing. So I can't complain about its condition.

  32. #32
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    Default Re: Joining rope end to end to make mast robands

    A lot of sails (especially older ones) use a twisted three-strand polyester line for the bolt rope, inside a Dacron tube sewn along the luff. It tends to be a special type of rope, made specifically for the job, which is twisted very tightly and is quite hard. This keeps it from getting squishy and deforming from its normal round shape and jamming inside a mast's bolt rope groove. These days, most sails are built using hard braided kernmantle luff line instead (with a smooth woven sheath over the core) but you still see plenty of three-strand stuff in use (partially because it is cheaper).

    Three strand rope is made by twisting the fibers until they kind of seize up into a bundle, then twisting multiple bundles together to make the rope. From day one there is a certain amount of tension in there as a result of all this twisting, and the length of a particular hunk of this stuff may not always stay the same as it ages. When the boltrope is installed in a new sail, it is usually and purposely installed to be slightly shorter than the edge of the sail fabric. This acts as a shock absorber and helps to prevent halyard tension from pulling the sail's seams apart. The rope takes the strain and acts as a stopper, so that the Dacron sailcloth doesn't have to.

    With age, it is not uncommon to have 3-strand bolt ropes shrink due to their twisty nature. The first telltale sign is when you start seeing that diamond-shaped surface pattern on the Dacron tube covering the boltrope. In some cases, this gets more and more defined and you start finding that your halyard system no longer has enough power to pull the sail's luff tight and smooth along the mast or spar. The shrunken boltrope gathers cloth alongside the mast, the halyard can't spread it back out where it is supposed to be, and the result is a baggy, overly drafty sail which the skipper has no good way to shape properly.

    Sails like this are frequently mislabeled as "blown out" due to their uncontrollable, excess draft. In reality, blown out is much more a matter of the cloth losing bias stability due to the yarns paralellograming and no longer being able to maintain their proper right angles to each other. A truly blown out sail can't really be fixed, but a sail exhibiting bad shape because of a shrunken boltrope usually can be. The rope itself can be replaced, but sometimes it can be left in and have just a short "addition" spliced into one end of it, allowing the cloth to be spread back out along the rope the way it was intended to be. It's not unusual to splice in a hunk that is 6"-8" long or more, especially if the boltrope comes down the mast, around the tack corner and continues along to the end of the boom.

    Your boltrope doesn't look horrible yet, but it is starting to show some signs and it is something to keep an eye on if you begin to lose the ability to adjust and control your mainsail draft.

  33. #33
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    Default Re: Joining rope end to end to make mast robands

    Quote Originally Posted by RichW View Post
    Just to give you skeptics an update on the dog collar mast hoops.....
    Sorry for being a smart a$$ mate - its a neat solution.
    It's all fun and games until Darth Vader comes.

  34. #34
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    Default Re: Joining rope end to end to make mast robands

    What happens when the dog wants to tack?

  35. #35
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    Default Re: Joining rope end to end to make mast robands

    Congrats for out-of-the-box thinking, and being creative.

    But try making a grommet out of stiff 3-strand, like manilla. It's actually very quick and easy. And then that skill is transferable to making wooden blocks.

    You can even make a grommet in place, in the ring in the sail. I do this for the tack of the mizzen on my 40 ft ketch, where the hold-down doesn't lead forward enough. Weave the grommet while it's passing through the cringle so you don't need any other attaching method.

    Don't use a soft rope, like nylon. The strands don't hold their shape.

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