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Overbend creases or not enough luff tension?

Discussion in 'Sail Trim with Don Guillette' started by Sublime, Jul 14, 2018. Add this thread to a FAQ

  1. Sublime

    Sublime

    Joined Aug 10, 2010
    177 posts, 0 likes
    Catalina 25
    US The mountains
    Ive got a new to me boat and this was my first time out with it so I’m working things out.
    Wind was very light, less than 5knts.

    I think I may need to get some sail kote on the lugs to help them slide up and down the mast. But pulled this up as far as I could then used the winch to get some tension. I don’t know how old or young the sail is. It is crisp. Wondering if it was just light winds or if I need to improve.

    And the outhaul needs improvement. Currently it’s a shackle with a rope tied to the boom. No adjusting it.
     

    Attached Files:



  2. JohnShannon

    JohnShannon

    Joined Jan 4, 2010
    672 posts, 63 likes
    Farr 30
    US San Francisco
    No expert, but it looks like outhaul tension is you #1 problem. If the halyard had too much tension you would have vertical creases right next to the mast. Usually the problem with halyard tension is ;you can winch it nice and tight then your rope clutch slips or your halyard stretches. The work around is to have a cunningham which puts down on the luff at the base of the mast and keeps tension.
     


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  3. Brian D

    Brian D Moderator

    Joined Feb 17, 2006
    3,959 posts, 626 likes
    Lancer 27PS
    US MCB Camp Pendleton, Ca KF6BL
    Hard to tell by the photo, but make sure (and I am sure you did this already) your topping lift is loose. Does not have to be all the way off, just so the boom pulls down on the sail.

    And congrats on the new to you boat.
     


    danstanford likes this.
  4. Ted

    Ted

    Joined Jan 26, 2005
    1,019 posts, 147 likes
    C&C 110
    US Bay Shore, Long Island, NY
    It looks like the bolt rope in the luff of the main has shrunk. It's an easy fix for a sailmaker or a DIY project if you're somewhat handy. There is lots of information on the internet about how to going about fixing this.
     


    Last edited: Jul 15, 2018
  5. SG

    SG

    Joined Feb 11, 2017
    1,045 posts, 170 likes
    J/Boat J/160
    US Annapolis
    Is the item circled '1' a reefing line to the clew? You need to tie that properly and/or ease it.
    upload_2018-7-15_8-26-5.png
    The reef line shouldn't be tight, or restrain the sail unless you're really reefing it. In that case it should go from the boom end, up through the cringle, then down to boom and tied to a loop with a slip knot. It looks way to high to just be reduced correctly by pulling it back to the boom end, to me.

    As for the Item 2 - you're lines of stress (my guess) is that stress lines comes from the reefing line and/or you just need to ease the boom up. If it were you outhaul, the sail would be too flat; but I can't tell that yet with all the other
    stuff that you need to do.

    As for the luff tension, DON'T winch the sail up too tight unless you have heavier air. You probably can get by on your boat with very little tension in LIGHT AIR.

    [​IMG]
     


    Last edited: Jul 15, 2018
    All U Get likes this.
  6. jssailem

    jssailem

    Joined Oct 22, 2014
    5,897 posts, 2,061 likes
    CAL 35 Cruiser
    US Salem, Moored Port Everett WA
    @Sublime for me there is some but not enough info in the picture to identify a specific issue. So I’m going to look at the basic question and try to help.
    Luff tension is used to position the center of power in the sail fore and aft. Here is a basic statement and a link to more information.
    Luff tension
    Luff tension changes the draft position. ie: the position of the maximum depth in the sail fore and aft. Usually this achieved with the cunningham eye. If your boat does not have a cunningham then the main halyard does the job. The maximum draft should be just forward of the middle of the sail most of the time.
    For more detail and other trim characteristics try: http://www.teamwindcraft.com/trimming-your-mainsail/
    The comment about the reef line by @SG was right on. Further the line you have for the reef looks a bit over stout for the job it is being asked to do. The line weight alone may be helping to create the wrinkles.
     


    Will Gilmore likes this.
  7. Brian D

    Brian D Moderator

    Joined Feb 17, 2006
    3,959 posts, 626 likes
    Lancer 27PS
    US MCB Camp Pendleton, Ca KF6BL
    It is possible that the sail itself is just too old, has lost its form, and needs to visit a sail doctor. My main is somewhat the same.
     


  8. Sublime

    Sublime

    Joined Aug 10, 2010
    177 posts, 0 likes
    Catalina 25
    US The mountains
    The reef system on this is also something that needs attention, I'm aware.
    The rigging on this boat is a mess and doesn't make sense to me. The topping lift was loose and that "reef line" didn't have any tension on it. I can get a nice shape on a sail, but this one is confusing me. Perhaps the sail does need some attention. It's very crisp so I'm not sure why it might be blown out. The previous owner was a new sailor and perhaps didn't maintain it well so it's stretched out in places?
    There isn't a sail loft local to me so I'd have to send it away. What pictures would help them? I might be interested in converting it to a loose footed main if I'm going to send it off.
    I'd like to get through this sailing season with it though then send it off when the water freezes over.
     


  9. Sublime

    Sublime

    Joined Aug 10, 2010
    177 posts, 0 likes
    Catalina 25
    US The mountains
    Thanks!
    Yes, that's how I have the topping lift adjusted. It has to be loose or it'll catch on the leech. The top section is wire so it looks straighter than it really is. The line that goes from boom to topping lift, back to boom was loose and blowing back.
     


  10. markwbird

    markwbird

    Joined Nov 26, 2012
    844 posts, 160 likes
    Hunter 34
    US Berkeley
    That looks like classic blown out mainsail. May be time to invest in a new sail
     


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  11. Sublime

    Sublime

    Joined Aug 10, 2010
    177 posts, 0 likes
    Catalina 25
    US The mountains
    I'm pretty handy with sewing.
    Is there a favorite source of info on doing this? It might get me through this summer at least.
     


  12. Sublime

    Sublime

    Joined Aug 10, 2010
    177 posts, 0 likes
    Catalina 25
    US The mountains
    Or perhaps I should remove the bolt rope all together since I have slugs. And then rework the rope on the foot?
     


  13. SG

    SG

    Joined Feb 11, 2017
    1,045 posts, 170 likes
    J/Boat J/160
    US Annapolis
    Sublime:
    You may need a new main -- but the picture doesn't tell me that.
    Is the sail loose footed or does it have a bolt rope along the mast; or, does it have slugs? (You might no be getting release from the foot of the sail so that a bunch of things are happening?)

    Take a picture of the sail so we can see the whole thing.
    Your wrinkles which run down at a diagonal toward the middle-ish of the boom tell me a much different story.
    A blown-out main has too much stretch in it, it can still be made to look much better than that.
    Excess halyard tension tends to show stress lines which are parallel with the mast.
    Excess outhall tension tends to flatten the sail (especially in the lower section).
    You topping lift, sheet, and that damn reefing line which is NOT RIGHT (or your picture is deceptive) is just probably the issue. If you have a VANG, please say so.

    I'm pretty confident that you can make that sail look a lot better and, while it might not be what you'll have around for a while, it probably can be made to work a lot better.
     


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  14. Sublime

    Sublime

    Joined Aug 10, 2010
    177 posts, 0 likes
    Catalina 25
    US The mountains
    The foot has a bolt rope. The luff has a bolt rope and slugs. I use the slugs. I have a vang. I'm going back up there this weekend with plans to rework some of that rigging. Also need to add some tell tales.
     


  15. Joe

    Joe

    Joined Jun 1, 2004
    6,467 posts, 325 likes
    Catalina 27
    US Mission Bay, San Diego
    Your boom is the culprit. The air is too light to fill the sail and the boom is drooping. causing the diagonal creases. This problem will disappear when the breeze picks up. In the mean time, tighten up the topping lift to take the weight off the sail. You'll have to readjust it every time you tack the boat, so, hopefully the control line is handy. If not, head up after the tack so you can reach it.... or extend the line towards the center of the mast with a clam cleat.... then it'll stay closer to the cockpit.
     


    SG likes this.
  16. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    2,735 posts, 1,167 likes
    O'Day 19
    US Littleton, NH
    A Cunningham would make a big difference. I'd like to see a side view of the whole rig, sheet, vang, Cunningham, topping lift,...

    - Will (Dragonfly)
     


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  17. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    2,735 posts, 1,167 likes
    O'Day 19
    US Littleton, NH
    A little deeper assessment-
    When I look at the picture you posted, what I see is the battened leach sagging into the center of the sail. There are wrinkles at each lug along the luff. This tells me that the boom could be pulled down to tighten both the aft end to lift the leach out and pull the tack downward and tighten the luff. A Cunningham would help, so would a vang.
    If you have changed the rake recently, the sail may be cut to accomidate a more acute angle at the tack for more rake. The angle of your boom should be horizontal at rest with the sail up and the topping lift no longer carrying any load.
    I thought the line I was looking at was a backstay. If that is the topping lift, it shouldn't be tight.
    Your sheet setup could also help trim the boom angle, so it would be very helpful to get a look at the whole rig. I don't think those wrinkles are necessarily from a blown out sail.

    - Will (Dragonfly)
     


    danstanford likes this.
  18. markwbird

    markwbird

    Joined Nov 26, 2012
    844 posts, 160 likes
    Hunter 34
    US Berkeley
    The topping lift is tight. It should not be. That is the problem. The boom needs to be able to pull down on the sail when you tighten the sheet. I can't if the topping lift goes taught. The topping lift should never be taught when the sail is up.
     


    danstanford likes this.

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