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Thread: Need ideas for furling line tensioner

  1. #1
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    Default Need ideas for furling line tensioner

    Damfino's mainmast is unstayed, round and rotating. The sail is boomless and furls/reefs on the spar. The mast is rotated by a furling line that rolls up on a composite spool just above the deck where the mast is about 6" in diameter. The furler line is run through a fairlead block to a dedicated winch on the house top. It all works much like a jib furler except that there is no housing around the spool to keep the furling line in order. Like a jib furler, when the sail is not reefed and there's no tension needed on the furler line, the mast rotates as the sail pulls one way or another and so it gives or takes a few inches of furler line on alternate tacks.

    As an alternative to a housing around the spool, I'm trying to think of a tensioning device for the furler line. It needs to permit the line to be let out or cranked in (The total travel is about 12 feet.), keep a couple of pounds of tension on the line and want to take back the last few inches of travel. The furler line is currently 3/8" Sta-Set-X, and i'm thinking of changing it to something lower stretch.

    Anybody got any ideas?

    Jim

  2. #2
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    Default Re: Need ideas for furling line tensioner

    This one is available via Sailrite -


    http://hitchcraft.net/index.html?gcl...FQENDQodjGmLcQ
    "The enemies of reason have a certain blind look."
    Doctor Jacquin to Lieutenant D'Hubert, in Ridley Scott's first major film _The Duellists_.

  3. #3
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    Default Re: Need ideas for furling line tensioner

    Quote Originally Posted by Thorne View Post
    This one is available via Sailrite -


    http://hitchcraft.net/index.html?gcl...FQENDQodjGmLcQ
    That's a clever gizmo. I'll find another use for it.
    Thanks.

  4. #4
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    Default Re: Need ideas for furling line tensioner

    They also make various angled hooks much simpler than the device above. If you rigged one on heavy shock cord, you might get the desired tensioning...


    http://www.firstmatescabin.com/bigimage/tugger.jpg
    http://www.amazon.com/dp/B000NFUXV8/...0&linkCode=asn
    "The enemies of reason have a certain blind look."
    Doctor Jacquin to Lieutenant D'Hubert, in Ridley Scott's first major film _The Duellists_.

  5. #5
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    Default Re: Need ideas for furling line tensioner

    Maybe a clamcleat on a shock cord.
    OR
    A 'handle' might be needed to keep things aligned.

    This might just work.

  6. #6
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    Default Re: Need ideas for furling line tensioner

    I like the tensioned cam cleat idea. I wonder if putting it on a slide on a short section of sail track would keep things under control and allow you to engage and disengage it with one hand?

  7. #7
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    Default Re: Need ideas for furling line tensioner

    Quote Originally Posted by Woxbox View Post
    I like the tensioned cam cleat idea. I wonder if putting it on a slide on a short section of sail track would keep things under control and allow you to engage and disengage it with one hand?
    This has potential.
    I'll post some pix tomorrow evening.

    Jim

  8. #8

    Default Re: Need ideas for furling line tensioner

    How about one of these turned backwards. seems it would keep the tension on the furling drum. Might have to take it apart and move the bail to the other side.



    http://www.westmarine.com/webapp/wcs...&ci_sku=277674

  9. #9
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    Default Re: Need ideas for furling line tensioner

    I have the same thing on Constance's jib reefing drum, there is enough movement in it when the sail slats to sometimes (ie a few times a day) let the line fall off, occasioning a stroll to the bow at, usually, a very inconvenient moment. My planned solution is a continuous loop of line passing a few times around the drum, and passing through a jam cleat and cheek block on the cabin top at the cockpit end. Some form of tensioning / adjustment could be arranged eg with a piece of shock cord inserted in the line, ideally at a point which will never pass round the drum or the block (allowing about 15ft of travel on my boat). To be 100% sure of a purchase on the drum the line would be fastened to it at a point, and half way through a sufficient number of turns, which lets you furl in either direction. The idea is cheap enough to experiment with anyway. The amount of line travel between fully set and furled is independent of drum diameter and equal to the perpendicular distance of the jib clew from the luff, not a lot on my boat, plus a couple of securing turns of the furled sail around the pole, so 15ft between block and drum should be enough to allow furling either way.
    Last edited by Dick Wynne; 06-07-2009 at 06:31 PM. Reason: Added last sentence

  10. #10
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    Smile Now: Who can stop my mizzen sheet wrapping around the bumkin end?

    The options appear to be:

    1) double the bumkin length but leave the sheet attachment where it is

    2) one of those conical plastic collars that stop dogs scratching head wounds

  11. #11
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    Default Re: Need ideas for furling line tensioner

    I was thinking along the lines of the traveller track and bungee too. It used to happen occasionally to me on the wykham martin gear and I'd imagined that I might make a wider spool base for it one day and slightly cupped just to prevent the line from dropping off under light or no tension. Just curved up slightly like a dinner plate. You could probably test the concept by cutting a plastic plate ( maybe a 20litre pail lid?)up and clipping butt blocking it back together to the furling drum.
    Last edited by John B; 06-07-2009 at 07:29 PM.

  12. #12
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    Default Re: Need ideas for furling line tensioner

    A picture is worth a few more words. So, to recap, the question is how to apply a bit of tension on the last few inches of furler line travel?



  13. #13
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    Default Re: Need ideas for furling line tensioner

    Hook or eye or small block on a bungee ,stressed off fair by 6 or 10 inches.
    Say across the cabintop, or down the cabin coaming to where the anchor is currently sitting. maybe even down at the junction of the forward beam.

  14. #14
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    Default Re: Need ideas for furling line tensioner

    Half a metre of shock cord under tension at 90 deg to the furling line. Put it halfway between the turning block and the winch with a light riding block on the furling line. Set it up with a cleat so the sideways tension can be adjusted. When the line is under load it will stretch the shock cord and allow the line to come straight, and when slack the shock cord will pull sideways taking the slack out.

    JohnWelsford

    Quote Originally Posted by JimConlin View Post
    Damfino's mainmast is unstayed, round and rotating. The sail is boomless and furls/reefs on the spar. The mast is rotated by a furling line that rolls up on a composite spool just above the deck where the mast is about 6" in diameter. The furler line is run through a fairlead block to a dedicated winch on the house top. It all works much like a jib furler except that there is no housing around the spool to keep the furling line in order. Like a jib furler, when the sail is not reefed and there's no tension needed on the furler line, the mast rotates as the sail pulls one way or another and so it gives or takes a few inches of furler line on alternate tacks.

    As an alternative to a housing around the spool, I'm trying to think of a tensioning device for the furler line. It needs to permit the line to be let out or cranked in (The total travel is about 12 feet.), keep a couple of pounds of tension on the line and want to take back the last few inches of travel. The furler line is currently 3/8" Sta-Set-X, and i'm thinking of changing it to something lower stretch.

    Anybody got any ideas?

    Jim
    An expert is but a beginner with experience.

  15. #15
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    Default Re: Need ideas for furling line tensioner

    Quote Originally Posted by john welsford View Post
    Half a metre of shock cord under tension at 90 deg to the furling line. Put it halfway between the turning block and the winch with a light riding block on the furling line. Set it up with a cleat so the sideways tension can be adjusted. When the line is under load it will stretch the shock cord and allow the line to come straight, and when slack the shock cord will pull sideways taking the slack out.

    JohnWelsford

    Thats what I was trying to say.Note to self.. must learn to communicate.

  16. #16
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    Default Re: Need ideas for furling line tensioner

    I think that'll do it, and more effectively and elegantly than the messes I was dreaming up. Thanks to all.

    Jim

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