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  1. #11
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    May 2001
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    Default Re: Lack of tension in tack of mainsail

    Quote Originally Posted by lw395 View Post
    looks like the reef tack line is tight and the sail hasn't been hoisted far enough?
    As other have said, try rigging a simple cunningham.
    Does the halyard even reach max height or does splice jam and prevent max hoist? a simple Cunningham is easier to tension lower sail than hauling from top.

    PS rig a simple tackle with lightish lines like dinghy stuff as the cunningham tensioner or if a spare winch nearby like for spi halyard, use that, can be let off iff winch needed elsewhere.
    Last edited by Robin; 18-09-19 at 10:41. Reason: PS
    Sermons from my pulpit are with tongue firmly in cheek and without any warranty!

  2. #12
    Join Date
    May 2007
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    38,141

    Default Re: Lack of tension in tack of mainsail

    We can't see the whole sail.
    Sails often get hoisted like this simply due to failure to let off the sheet and kicker adequately.

    That looks like a shelf foot, so the precise level of the tack relative to the fronot of the boom will be less important than luff tension and leach tension.
    Really need to get the slack out of the luff before having an opinion on the 'knockback' of the tack, ie, does it need to be more or less aft of the gooseneck.
    Bear in mind that a slack luff is not always a bad thing, e.g. when off the wind in conditions where you are not overpowered.

    Good point about is the halyard actually able to take the tack higher or is it maxed out with the splice in the sheave or whatever.

  3. #13
    Join Date
    Mar 2004
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    10,490

    Default Re: Lack of tension in tack of mainsail

    1st off, ignore the stuff about the tack being too high. I don't buy that, looks fine to me. If that was an issue I'd expect a massive crease from the start of the shelf diagonally up to the luff, i.e the foot line being pulled up out of the boom. We don't see that, so I'm not seeing that as an issue.

    If the luff tension in the top 1/3 of the sail looks considerably higher, but the bottom looks like that then clearly the luff sliders aren't doing a good job of sliding.... Liberally apply lube and try again, also look for obvious signs of damage on the sliders, replacing if necessary. In general you will get plenty of friction with sliders like that, so you would expect to see a difference in tension as you go up the luff. As others have said, if you can't reduce the friction in the sliders enough (and there is a reason people use ball race cars beyond just looking cool...) then using a cunningham is an acceptable compromise.
    Also worth saying that your pictures have the sail well eased, which is obviously putting a sideways pressure on your sliders. I'm sure that this is teaching granny to suck eggs, but If you're trying to put luff tension into that sail on that point of sail, then very obviously it won't go anywhere, as those simple plastic sliders are basically jammed into the mast slot at that point. I would come head to wind, make sure that the sheet, kicker and all reefing lines are completely free and then wind in the tension. I'd also leave the halyard on the winch if possible, all clutches will slip with loads of tension on them and you'll notice it at the bottom first.

    But also.... I wouldn't worry too much about this from a cruising perspective. It looks ugly but it's not hurting your performance too badly providing the luff tension is there higher up the sail. Especially on a reach...
    You never know, I might be right!

  4. #14
    Join Date
    Aug 2011
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    On the Celtic Fringe
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    14,333

    Default Re: Lack of tension in tack of mainsail

    Quote Originally Posted by langstonelayabout View Post
    4 - Be honest. How old is your sail. If you are looking for good performance you won't have a sail that is more than about 3 seasons old. The older, the lesser performance. I recently viewed a boat that had 20 year old sails that were 'very good'. Yeah, right. They were good for the bin.
    Can you drop your three season sails round to me and other deserving cruising sailors please?
    Cynical Scottish very nearly retired engineer who sails a Gib'Sea 96.

  5. #15
    Join Date
    Mar 2017
    Location
    Me; Nth County Dublin, Boat;Malahide
    Posts
    840

    Default Re: Lack of tension in tack of mainsail

    Quote Originally Posted by thinwater View Post
    This. Easing the #1 reef and lowering the tack may be enough.

    And yes, that is for a cuninghham. Run the line up through the hole and back down for an extra 2:1 purchase.
    The #1 reef looks to have no slack in it, but it's not affecting the situation, because you can see a curve in the luff above it.

  6. #16
    Join Date
    Mar 2017
    Location
    Me; Nth County Dublin, Boat;Malahide
    Posts
    840

    Default Re: Lack of tension in tack of mainsail

    Quote Originally Posted by lw395 View Post
    looks like the reef tack line is tight and the sail hasn't been hoisted far enough?
    As other have said, try rigging a simple cunningham.
    No there is a curve in the luff above the reef.

  7. #17
    Join Date
    May 2001
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    where democracy needs no guns
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    Default Re: Lack of tension in tack of mainsail

    Quote Originally Posted by flaming View Post
    1st off, ignore the stuff about the tack being too high. I don't buy that, looks fine to me. If that was an issue I'd expect a massive crease from the start of the shelf diagonally up to the luff, i.e the foot line being pulled up out of the boom. We don't see that, so I'm not seeing that as an issue.

    If the luff tension in the top 1/3 of the sail looks considerably higher, but the bottom looks like that then clearly the luff sliders aren't doing a good job of sliding.... Liberally apply lube and try again, also look for obvious signs of damage on the sliders, replacing if necessary. In general you will get plenty of friction with sliders like that, so you would expect to see a difference in tension as you go up the luff. As others have said, if you can't reduce the friction in the sliders enough (and there is a reason people use ball race cars beyond just looking cool...) then using a cunningham is an acceptable compromise.
    Also worth saying that your pictures have the sail well eased, which is obviously putting a sideways pressure on your sliders. I'm sure that this is teaching granny to suck eggs, but If you're trying to put luff tension into that sail on that point of sail, then very obviously it won't go anywhere, as those simple plastic sliders are basically jammed into the mast slot at that point. I would come head to wind, make sure that the sheet, kicker and all reefing lines are completely free and then wind in the tension. I'd also leave the halyard on the winch if possible, all clutches will slip with loads of tension on them and you'll notice it at the bottom first.

    But also.... I wouldn't worry too much about this from a cruising perspective. It looks ugly but it's not hurting your performance too badly providing the luff tension is there higher up the sail. Especially on a reach...
    It also looks like a fully battened main and the battens may be adjusted too tight and adding to pressure on the sliders. Our last fb sail had roller bearing cars on a track and could be raised easy all bar the last bit because initially the splice taper in the original halyard jammed in the top sheave, winding on more tension just stretched the halyard. Solved by a new Dyneema halyard knotted to the head shackle (I forget the knot name but easy to tie safe and secure as well as short.) I also put a line through the Cunningham to a redundant mast winch ( everything else went back to cockpit coachroof self tailers plus HD clutches. hoisting was easy without using winch handles except for final tweak and very last knockings on the cunning ham THE mainsail was a radial cut one in Hydranet and loose footed. In my case the cunning ham's eye was intended as the tack hole for the flattener reef, and rarely used as such unless set up in harbour prior to departure by hooking on a redundant 'horn'. We had a 3 reef slab main with 2 line reefing and all lines to the cockpit
    Last edited by Robin; 18-09-19 at 13:49. Reason: sp stutters
    Sermons from my pulpit are with tongue firmly in cheek and without any warranty!

  8. #18
    Join Date
    Mar 2004
    Posts
    10,490

    Default Re: Lack of tension in tack of mainsail

    Quote Originally Posted by Robin View Post
    Solved by a new Dyneema halyard knotted to the head shackle (I forget the knot name but easy to tie safe and secure as well as short.)
    Just known as the halyard knot I think.....

    https://www.animatedknots.com/halyard-hitch-knot
    You never know, I might be right!

  9. #19
    Join Date
    Jan 2003
    Location
    Clyde
    Posts
    7,390

    Default Re: Lack of tension in tack of mainsail

    Does your main sail go up easily or do you need to use the winch before it’s all the way up. I had a similar problem for years and was caused by there being no main halyard sheave at the top of the mast. The halyard was just running over a spindle that used to have a sheave around it. Once replaced the difference was incredible. As other have said poor running sail slides can cause your problem or even a twisted mast.

  10. #20
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    May 2001
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    Default Re: Lack of tension in tack of mainsail

    Quote Originally Posted by flaming View Post
    Just known as the halyard knot I think.....

    https://www.animatedknots.com/halyard-hitch-knot
    That's the one! only possible problem is undoing it if ever required after long periods under high load, no sweat if end for ending the halyard of course or if enough spare to cut off a length.
    Sermons from my pulpit are with tongue firmly in cheek and without any warranty!

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