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Re: [Michalak] Re: Lug Luffs

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  • Anders Bjorklund
    Controlling twist is important. With that boom parrel arrangement, it would be interesting to see how far aft on the boom the downhaul (/vang) could be
    Message 1 of 28 , Jun 4, 2013
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      Controlling twist is important. With that boom parrel arrangement, it would
      be interesting to see how far aft on the boom the "downhaul" (/vang) could
      be attached, before luff tension begins to suffer. It wouldn't need to be
      very far to duplicate the geometrical mechanical advantage of a typical
      boom vang. Remember that with a balance lug, the leverage fulcrum is
      located significantly forward of the mast, and the tackle is also pulling
      more directly downward, instead of thrusting the boom forward. I think it
      would be a worthwhile (and zero cost) experiment to try.

      Anders


      On Tue, Jun 4, 2013 at 1:11 PM, CHARLES <chuckpierce@...> wrote:

      > I think, though, that you have to have something like a vang that is
      > attached further aft on the boom if you really want to control sail twist,
      > and that is the key to both downwind and upwind performance...
      >


      [Non-text portions of this message have been removed]
    • John Trussell
      I m easily confused, but. I always thought that one of the virtues of a balanced lug is that it is more or less self-vanging. The sail is suspended between the
      Message 2 of 28 , Jun 4, 2013
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        I'm easily confused, but.



        I always thought that one of the virtues of a balanced lug is that it is
        more or less self-vanging. The sail is suspended between the halyard
        attached to the yard and the downhaul attached to the boom. The tendency of
        the boom to rise is offset by the tension on the sail's luff. If you apply
        tension to a vang, this should ease tension on the luff, allowing the yard
        to sag, increasing twist and sail fullness. What am I missing here?



        JohnT

        _____

        From: Michalak@yahoogroups.com [mailto:Michalak@yahoogroups.com] On Behalf
        Of Anders Bjorklund
        Sent: Tuesday, June 04, 2013 2:54 PM
        To: Michalak@yahoogroups.com
        Subject: Re: [Michalak] Re: Lug Luffs





        Controlling twist is important. With that boom parrel arrangement, it would
        be interesting to see how far aft on the boom the "downhaul" (/vang) could
        be attached, before luff tension begins to suffer. It wouldn't need to be
        very far to duplicate the geometrical mechanical advantage of a typical
        boom vang. Remember that with a balance lug, the leverage fulcrum is
        located significantly forward of the mast, and the tackle is also pulling
        more directly downward, instead of thrusting the boom forward. I think it
        would be a worthwhile (and zero cost) experiment to try.

        Anders

        On Tue, Jun 4, 2013 at 1:11 PM, CHARLES <chuckpierce@...
        <mailto:chuckpierce%40sbcglobal.net> > wrote:

        > I think, though, that you have to have something like a vang that is
        > attached further aft on the boom if you really want to control sail twist,
        > and that is the key to both downwind and upwind performance...
        >

        [Non-text portions of this message have been removed]





        [Non-text portions of this message have been removed]
      • CHARLES
        Guys, I will be on the water in South Texas all next week, and if conditions are mild enough to experiment, I ll rig it that way and let you know how it turns
        Message 3 of 28 , Jun 4, 2013
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          Guys, I will be on the water in South Texas all next week, and if conditions are mild enough to experiment, I'll rig it that way and let you know how it turns out.

          And I'm not saying that twist is inherently bad except dead downwind, where you get into the deathroll scenario, and close hauled, where you may want no twist at all so that you can sail closer to the wind and make it up a narrow channel without tacking or worse, rowing. :) Regardless of point of sail, I think that it is good to be able to decide for yourself how much twist you want, but it is certainly not necessary to go to all of this trouble to have fun in one of Jim's boats.

          Chuck P


          --- In Michalak@yahoogroups.com, Anders Bjorklund <andersbjorklund5@...> wrote:
          >
          > Controlling twist is important. With that boom parrel arrangement, it would
          > be interesting to see how far aft on the boom the "downhaul" (/vang) could
          > be attached, before luff tension begins to suffer. It wouldn't need to be
          > very far to duplicate the geometrical mechanical advantage of a typical
          > boom vang. Remember that with a balance lug, the leverage fulcrum is
          > located significantly forward of the mast, and the tackle is also pulling
          > more directly downward, instead of thrusting the boom forward. I think it
          > would be a worthwhile (and zero cost) experiment to try.
          >
          > Anders
          >
          >
          > On Tue, Jun 4, 2013 at 1:11 PM, CHARLES <chuckpierce@...> wrote:
          >
          > > I think, though, that you have to have something like a vang that is
          > > attached further aft on the boom if you really want to control sail twist,
          > > and that is the key to both downwind and upwind performance...
          > >
          >
          >
          > [Non-text portions of this message have been removed]
          >
        • Anders Bjorklund
          John, you re not confused -- unless it s because you don t realize that you re seeing things clearly. :-) What you really might not realize is that Chuck has
          Message 4 of 28 , Jun 4, 2013
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            John, you're not confused -- unless it's because you don't realize that
            you're seeing things clearly. :-)

            What you really might not realize is that Chuck has his Mayfly 14 rigged
            differently than the usual balance lug. If I'm not mistaken, he has both a
            luff downhaul and a boom vang like Brian Pearson had on his Lymington Scow.
            The luff downhaul is attached to the very fore end of the boom, rather than
            near the mast, and the boom vang is attached quite a ways aft on the boom.
            If you tighten his boom vang, it drives the boom forward (and downward),
            which increases the tension on the downhaul tackle, which also tightens the
            luff. It does allow advanced control of sail tensions, but comes at the
            cost of more complication and expense (IMHO).

            Anders


            On Tue, Jun 4, 2013 at 4:53 PM, John Trussell <jtrussell2@...> wrote:

            > I always thought that one of the virtues of a balanced lug is that it is
            > more or less self-vanging. The sail is suspended between the halyard
            > attached to the yard and the downhaul attached to the boom. The tendency of
            > the boom to rise is offset by the tension on the sail's luff. If you apply
            > tension to a vang, this should ease tension on the luff, allowing the yard
            > to sag, increasing twist and sail fullness. What am I missing here?
            >


            [Non-text portions of this message have been removed]
          • Anders Bjorklund
            Lucky you! But are you sure you re unbiased? I ll test it too, but can tell you right now it s a fabulous system. ;-) Anders ... [Non-text portions of this
            Message 5 of 28 , Jun 4, 2013
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              Lucky you! But are you sure you're unbiased? I'll test it too, but can tell
              you right now it's a fabulous system. ;-)

              Anders


              On Tue, Jun 4, 2013 at 5:05 PM, CHARLES <chuckpierce@...> wrote:

              > Guys, I will be on the water in South Texas all next week, and if
              > conditions are mild enough to experiment, I'll rig it that way and let you
              > know how it turns out.


              [Non-text portions of this message have been removed]
            • CHARLES
              To pull all or even most of the twist out of a balanced lug with only a downhaul would require a large purchase and a heavily reinforced luff. Even close
              Message 6 of 28 , Jun 4, 2013
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                To pull all or even most of the twist out of a balanced lug with only a downhaul would require a large purchase and a heavily reinforced luff. Even close hauled, where the sheet helps the sail be "self vanging" there is a fair amount of twist without an actual boom vang. The degree of this twist is not always apparent to the driver of the lug rigged boat. I first noticed it on the Mayfly in pictures taken from other boats, and that sparked my interest in this stuff. When you harden down on the vang on my boat, the tension is transferred through the leach of my loose footed sail through the yard back to the luff. The luff does not ease at all as the vang is applied. The leach tightens up and the yard moves progressively closer to parallel with the boom. If you don't have a really stiff yard, the yard bends a bit more and changes the shape of the head of the sail, as well.

                Chuck P

                --- In Michalak@yahoogroups.com, "John Trussell" <jtrussell2@...> wrote:
                >
                > I'm easily confused, but.
                >
                >
                >
                > I always thought that one of the virtues of a balanced lug is that it is
                > more or less self-vanging. The sail is suspended between the halyard
                > attached to the yard and the downhaul attached to the boom. The tendency of
                > the boom to rise is offset by the tension on the sail's luff. If you apply
                > tension to a vang, this should ease tension on the luff, allowing the yard
                > to sag, increasing twist and sail fullness. What am I missing here?
                >
                >
                >
                > JohnT
                >
                > _____
                >
                > From: Michalak@yahoogroups.com [mailto:Michalak@yahoogroups.com] On Behalf
                > Of Anders Bjorklund
                > Sent: Tuesday, June 04, 2013 2:54 PM
                > To: Michalak@yahoogroups.com
                > Subject: Re: [Michalak] Re: Lug Luffs
                >
                >
                >
                >
                >
                > Controlling twist is important. With that boom parrel arrangement, it would
                > be interesting to see how far aft on the boom the "downhaul" (/vang) could
                > be attached, before luff tension begins to suffer. It wouldn't need to be
                > very far to duplicate the geometrical mechanical advantage of a typical
                > boom vang. Remember that with a balance lug, the leverage fulcrum is
                > located significantly forward of the mast, and the tackle is also pulling
                > more directly downward, instead of thrusting the boom forward. I think it
                > would be a worthwhile (and zero cost) experiment to try.
                >
                > Anders
                >
                > On Tue, Jun 4, 2013 at 1:11 PM, CHARLES <chuckpierce@...
                > <mailto:chuckpierce%40sbcglobal.net> > wrote:
                >
                > > I think, though, that you have to have something like a vang that is
                > > attached further aft on the boom if you really want to control sail twist,
                > > and that is the key to both downwind and upwind performance...
                > >
                >
                > [Non-text portions of this message have been removed]
                >
                >
                >
                >
                >
                > [Non-text portions of this message have been removed]
                >
              • CHARLES
                Oh, I ll take some video and let you make up your own mind. This year we have 45-50 miles between camps on 3 days so I ll be on the water 10 or 11 hours on
                Message 7 of 28 , Jun 4, 2013
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                  Oh, I'll take some video and let you make up your own mind. This year we have 45-50 miles between camps on 3 days so I'll be on the water 10 or 11 hours on those days. There should be time to check it out :)
                  So you have sailed a balanced lug rigged that way?

                  Chuck P

                  --- In Michalak@yahoogroups.com, Anders Bjorklund <andersbjorklund5@...> wrote:
                  >
                  > Lucky you! But are you sure you're unbiased? I'll test it too, but can tell
                  > you right now it's a fabulous system. ;-)
                  >
                  > Anders
                  >
                  >
                  > On Tue, Jun 4, 2013 at 5:05 PM, CHARLES <chuckpierce@...> wrote:
                  >
                  > > Guys, I will be on the water in South Texas all next week, and if
                  > > conditions are mild enough to experiment, I'll rig it that way and let you
                  > > know how it turns out.
                  >
                  >
                  > [Non-text portions of this message have been removed]
                  >
                • CHARLES
                  And I ll say this, then I have to go finish packing for the 200-If I am out sailing for the afternoon with the grandkids in this boat, I don t usually even rig
                  Message 8 of 28 , Jun 4, 2013
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                    And I'll say this, then I have to go finish packing for the 200-If I am out sailing for the afternoon with the grandkids in this boat, I don't usually even rig all that stuff. I position the downhaul where Jim shows it in his book and get into the water as quick as I can. On a long trip in rough conditions out in the middle of nowhere however I want every advantage I can possibly have. You guys have a good week!

                    Chuck P

                    --- In Michalak@yahoogroups.com, Anders Bjorklund <andersbjorklund5@...> wrote:
                    >
                    > John, you're not confused -- unless it's because you don't realize that
                    > you're seeing things clearly. :-)
                    >
                    > What you really might not realize is that Chuck has his Mayfly 14 rigged
                    > differently than the usual balance lug. If I'm not mistaken, he has both a
                    > luff downhaul and a boom vang like Brian Pearson had on his Lymington Scow.
                    > The luff downhaul is attached to the very fore end of the boom, rather than
                    > near the mast, and the boom vang is attached quite a ways aft on the boom.
                    > If you tighten his boom vang, it drives the boom forward (and downward),
                    > which increases the tension on the downhaul tackle, which also tightens the
                    > luff. It does allow advanced control of sail tensions, but comes at the
                    > cost of more complication and expense (IMHO).
                    >
                    > Anders
                    >
                    >
                    > On Tue, Jun 4, 2013 at 4:53 PM, John Trussell <jtrussell2@...> wrote:
                    >
                    > > I always thought that one of the virtues of a balanced lug is that it is
                    > > more or less self-vanging. The sail is suspended between the halyard
                    > > attached to the yard and the downhaul attached to the boom. The tendency of
                    > > the boom to rise is offset by the tension on the sail's luff. If you apply
                    > > tension to a vang, this should ease tension on the luff, allowing the yard
                    > > to sag, increasing twist and sail fullness. What am I missing here?
                    > >
                    >
                    >
                    > [Non-text portions of this message have been removed]
                    >
                  • prairiedog2332
                    Another thing Jim advises is to attach the halyard further up the yard to help prevent sail twist. 40% up rather than 33% as generally seen in older
                    Message 9 of 28 , Jun 4, 2013
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                      Another thing Jim advises is to attach the halyard further up the yard
                      to help prevent sail twist. 40% up rather than 33% as generally seen in
                      older literature and he explain why on page 68. It may only apply to
                      lines that tend to stretch a bit?
                      When a boom vang is tightened it also flattens the sail as well as to
                      help prevent twisting of the upper end of the yard, which might aid
                      going upwind. One can also do that by adding a multi-part lead
                      arrangement on the main-sheet. Storer explains here and used no vang.

                      http://www.youtube.com/watch?v=YA9ttyg5xXU
                      <http://www.youtube.com/watch?v=YA9ttyg5xXU>

                      In a cat yawl Bolger suggests somewhere if doing a lot of downind
                      running, for better control over the dreaded death roll install a larger
                      mizzen and go wing on wing with a reef in the main. Works best with a
                      fully battened mizzen if you don't mind the extra work in making it.
                      That way it won't slat and flutter as much at anchor and you can feather
                      it if it develops too much weather helm . A fully battened standing lug
                      mizzen is the best way to go he has mentioned as it doesn't have to tied
                      to the mast. But will not wrap up around the mast like a LOM so needs
                      some place to store it if taken down. It also has more area up high if
                      you have a birdwatcher cabin.

                      Nels

                      --- In Michalak@yahoogroups.com, "CHARLES" wrote:
                      >
                      > Guys, I will be on the water in South Texas all next week, and if
                      conditions are mild enough to experiment, I'll rig it that way and let
                      you know how it turns out.
                      >
                      > And I'm not saying that twist is inherently bad except dead downwind,
                      where you get into the deathroll scenario, and close hauled, where you
                      may want no twist at all so that you can sail closer to the wind and
                      make it up a narrow channel without tacking or worse, rowing. :)
                      Regardless of point of sail, I think that it is good to be able to
                      decide for yourself how much twist you want, but it is certainly not
                      necessary to go to all of this trouble to have fun in one of Jim's
                      boats.
                      >
                      > Chuck P
                      >
                      >




                      [Non-text portions of this message have been removed]
                    • jhargrovewright2@juno.com
                      John T, You ain t missin nothing. The balanced lug is self vanging. If there is much twist in the sail the yard is not in the correct place in relation to
                      Message 10 of 28 , Jun 4, 2013
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                        John T, You ain't missin nothing. The balanced lug is self vanging. If there is much twist in the sail the yard is not in the correct place in relation to the mast. That is the simple answer.... Of course the boom and yard are never going to be exactly the same but should be rather close on most points of sail. JIB

                        ---------- Original Message ----------
                        From: "John Trussell" <jtrussell2@...>
                        To: <Michalak@yahoogroups.com>
                        Subject: RE: [Michalak] Re: Lug Luffs
                        Date: Tue, 4 Jun 2013 17:53:49 -0400


                        <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                        I'm easily confused, but.

                        I always thought that one of the virtues of a balanced lug is that it is
                        more or less self-vanging. The sail is suspended between the halyard
                        attached to the yard and the downhaul attached to the boom. The tendency of
                        the boom to rise is offset by the tension on the sail's luff. If you apply
                        tension to a vang, this should ease tension on the luff, allowing the yard
                        to sag, increasing twist and sail fullness. What am I missing here?

                        JohnT

                        _____

                        From: Michalak@yahoogroups.com [mailto:Michalak@yahoogroups.com] On Behalf
                        Of Anders Bjorklund
                        Sent: Tuesday, June 04, 2013 2:54 PM
                        To: Michalak@yahoogroups.com
                        Subject: Re: [Michalak] Re: Lug Luffs

                        Controlling twist is important. With that boom parrel arrangement, it would
                        be interesting to see how far aft on the boom the "downhaul" (/vang) could
                        be attached, before luff tension begins to suffer. It wouldn't need to be
                        very far to duplicate the geometrical mechanical advantage of a typical
                        boom vang. Remember that with a balance lug, the leverage fulcrum is
                        located significantly forward of the mast, and the tackle is also pulling
                        more directly downward, instead of thrusting the boom forward. I think it
                        would be a worthwhile (and zero cost) experiment to try.

                        Anders

                        On Tue, Jun 4, 2013 at 1:11 PM, CHARLES <chuckpierce@...
                        <mailto:chuckpierce%40sbcglobal.net> > wrote:

                        > I think, though, that you have to have something like a vang that is
                        > attached further aft on the boom if you really want to control sail twist,
                        > and that is the key to both downwind and upwind performance...
                        >

                        [Non-text portions of this message have been removed]

                        [Non-text portions of this message have been removed]







                        [Non-text portions of this message have been removed]
                      • Anders Bjorklund
                        Because of the geometry, I would assert that less purchase would actually be required in a more vertically oriented downhaul tackle than in a more horizontally
                        Message 11 of 28 , Jun 4, 2013
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                          Because of the geometry, I would assert that less purchase would actually
                          be required in a more vertically oriented downhaul tackle than in a more
                          horizontally oriented vang tackle. Much of the power of a boom vang like
                          that just acts to increase compression forces on the boom, which are
                          largely wasted.

                          Regarding a heavily reinforced luff, I think that how the downward forces
                          are applied to the boom does not make any difference. Reducing sail twist
                          requires high leech tension. The yard of a lug sail acts as a pivot around
                          the point where the halyard attaches, which is usually not far from its
                          midpoint. If you pull down on the leech, the yard pivots on its halyard,
                          and its forward end rises. So increasing leech tension automatically
                          increases luff tension. Higher luff tensions can be induced by moving the
                          halyard attachment point forward on the yard, but that will make it more
                          difficult to reduce sail twist, not less.

                          Are there errors in my thinking?

                          Anders


                          On Tue, Jun 4, 2013 at 5:29 PM, CHARLES <chuckpierce@...> wrote:

                          > To pull all or even most of the twist out of a balanced lug with only a
                          > downhaul would require a large purchase and a heavily reinforced luff.


                          [Non-text portions of this message have been removed]
                        • prairiedog2332
                          An advantage of a lug sail is that the luff is in the free flow of air - free from disturbances around a mast - and the thinner the luff the better, so is why
                          Message 12 of 28 , Jun 4, 2013
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                            An advantage of a lug sail is that the luff is in the free flow of air -
                            free from disturbances around a mast - and the thinner the luff the
                            better, so is why I suggested pack-strap tape reinforcement sewn in on a
                            poly tarp sail rather than a bolt rope. Could it be welded in place with
                            something that sticks to poly also entered my thoughts? Or some really
                            sticky tape of which there is a kind for patching poly tarp, just to try
                            it out?

                            A vang attached to the top end of the yard running back to the helm
                            position in the stern might help prevent yard twist and also tension the
                            luff. In larger hulls with big heavy yards the weight of the yard served
                            the purpose but with a lighter yard attached to a halyard further aft it
                            might add some more tension set up like that?

                            Nels

                            --- In Michalak@yahoogroups.com, Anders Bjorklund wrote:
                            >
                            > Because of the geometry, I would assert that less purchase would
                            actually
                            > be required in a more vertically oriented downhaul tackle than in a
                            more
                            > horizontally oriented vang tackle. Much of the power of a boom vang
                            like
                            > that just acts to increase compression forces on the boom, which are
                            > largely wasted.
                            >
                            > Regarding a heavily reinforced luff, I think that how the downward
                            forces
                            > are applied to the boom does not make any difference. Reducing sail
                            twist
                            > requires high leech tension. The yard of a lug sail acts as a pivot
                            around
                            > the point where the halyard attaches, which is usually not far from
                            its
                            > midpoint. If you pull down on the leech, the yard pivots on its
                            halyard,
                            > and its forward end rises. So increasing leech tension automatically
                            > increases luff tension. Higher luff tensions can be induced by moving
                            the
                            > halyard attachment point forward on the yard, but that will make it
                            more
                            > difficult to reduce sail twist, not less.
                            >
                            > Are there errors in my thinking?
                            >
                            > Anders




                            [Non-text portions of this message have been removed]
                          • Cod
                            Keeping luff tension by avoiding mast, boom and yard bend is first and foremost. If you ve got stiff spars you can play with the rest. My Cheap Pages has a
                            Message 13 of 28 , Jun 4, 2013
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                              Keeping luff tension by avoiding mast, boom and yard bend is first and foremost. If you've got stiff spars you can play with the rest.

                              My Cheap Pages has a different approach, see the Conor O'Brien link to his Gunter Sprit. http://www.thecheappages.com/boat/cob/COB_sea-boat.html

                              Whack-boing! It's dub!
                              www.thecheappages.com



                              [Non-text portions of this message have been removed]
                            • prairiedog2332
                              Thanks Craig, I guess with a cat yawl one would run the yard vang back to the mizzen mast and down so it would be up and out of the way of the aft end of the
                              Message 14 of 28 , Jun 5, 2013
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                                Thanks Craig,

                                I guess with a cat yawl one would run the yard vang back to the mizzen
                                mast and down so it would be up and out of the way of the aft end of the
                                boom?

                                Nels


                                --- In Michalak@yahoogroups.com, Cod wrote: >
                                > Keeping luff tension by avoiding mast, boom and yard bend is first and
                                foremost. If you've got stiff spars you can play with the rest.
                                >
                                > My Cheap Pages has a different approach, see the Conor O'Brien link to
                                his Gunter Sprit.
                                http://www.thecheappages.com/boat/cob/COB_sea-boat.html
                                >
                                > Whack-boing! It's dub!
                                > www.thecheappages.com
                                >
                                >
                                >
                                > [Non-text portions of this message have been removed]
                                >



                                [Non-text portions of this message have been removed]
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