Loading ...
Sorry, an error occurred while loading the content.

How tight is too tight

Expand Messages
  • Michael Sloan
    Hey folks, I ll be stepping my mast this weekend and I was wondering how tight (or how much tension) is too much. I am looking into picking up a tension tool,
    Message 1 of 19 , Mar 2, 2004
    • 0 Attachment
      Hey folks, I'll be stepping my mast this weekend and I was wondering
      how tight (or how much tension) is too much. I am looking into
      picking up a tension tool, but is it worth it?

      Any info is more than I have now.


      I have my rudder off and it's about 4 feet long. (Just the rudder)
      If you want I'll take a picture and Next to a yard stick and E-Mail
      it to whoever

      Thanks Mike
    • Dave Brezina
      If your forestay is the right length, then my guess is you can t make the shrouds too tight, because the mast will bend, as intended, and that will give you a
      Message 2 of 19 , Mar 2, 2004
      • 0 Attachment
        If your forestay is the right length, then my guess is you can't make
        the shrouds too tight, because the mast will bend, as intended, and
        that will give you a good, flat, mainsail shape.

        Having screwed up the forestay by overtightening to compensate for a
        boatyard error in headfoil length (Scorpion has roller furling), I can
        unequivocally say that if everything is too tight, you can compress
        the deck causing bucking and delamination. That's bad.

        But what I don't get is how a guage would help with a normal mast rake
        -- the forestay the right length. Since the mast is designed to bend,
        and it can also be misaligned athwartship, wouldn't the guage reach an
        equilibrium? So your port and starboard shrouds would always be the
        same? And if the mast bends and the stay is the right length,
        wouldn't the tension be the same in each component of the standing
        rigging? And, of course applying backstay tension changes the whole
        system. So, although I like gizmos, the $70 or so for each guage (the
        size range didn't cover both inner and outer shrouds the last time I
        looked) it seems to me like the investment would be better in
        something like new shrouds, babystay, or pair of turnbuckles. Maybe
        I'm missing something.

        Look at the group's files sections for "mast tuning" articles.

        Dave Brezina
        Scorpion
        Chicago






        --- In SJ-24@yahoogroups.com, "Michael Sloan" <eddieaacc@y...> wrote:
        > Hey folks, I'll be stepping my mast this weekend and I was wondering
        > how tight (or how much tension) is too much. I am looking into
        > picking up a tension tool, but is it worth it?
        >
        > Any info is more than I have now.
        >
        >
        > I have my rudder off and it's about 4 feet long. (Just the rudder)
        > If you want I'll take a picture and Next to a yard stick and E-Mail
        > it to whoever
        >
        > Thanks Mike
      • J. L. Jones
        Why dontcha post it in the photos or files section for all the group to access? Later J. L. ... J. L. Jones Brownsboro Shipyards n35°45.334 w086°27.685
        Message 3 of 19 , Mar 2, 2004
        • 0 Attachment
          Why dontcha' post it in the photos or files section for all the group to
          access?


          Later

          J. L.




          >snip....
          >
          >I have my rudder off and it's about 4 feet long. (Just the rudder)
          >If you want I'll take a picture and Next to a yard stick and E-Mail
          >it to whoever
          >
          >Thanks Mike
          >
          >
          >Yahoo! Groups Sponsor
          >ADVERTISEMENT
          ><http://rd.yahoo.com/SIG=12c2mb1d8/M=274551.4550177.5761904.1261774/D=egroupweb/S=1705065792:HM/EXP=1078364863/A=2019528/R=2/SIG=1413460af/*http://ad.doubleclick.net/jump/N3349.yahoo1/B1282054.27;abr=!ie4;abr=!ie5;sz=300x250;code=18634;dcopt=rcl;ord=1078278463242978?>Click
          >Here
          >
          >
          >----------
          >Yahoo! Groups Links
          > * To visit your group on the web, go to:
          > *
          > <http://groups.yahoo.com/group/SJ-24/>http://groups.yahoo.com/group/SJ-24/
          > *
          > * To unsubscribe from this group, send an email to:
          > *
          > <mailto:SJ-24-unsubscribe@yahoogroups.com?subject=Unsubscribe>SJ-24-unsubscribe@yahoogroups.com
          >
          > *
          > * Your use of Yahoo! Groups is subject to the
          > <http://docs.yahoo.com/info/terms/>Yahoo! Terms of Service.
          >
          >---
          >Incoming mail is certified Virus Free.
          >Checked by AVG anti-virus system (http://www.grisoft.com).
          >Version: 6.0.594 / Virus Database: 377 - Release Date: 2/24/04

          J. L. Jones
          Brownsboro Shipyards
          n35°45.334 w086°27.685
          photographsbyjl@...

          ----------


          ---
          Outgoing mail is certified Virus Free.
          Checked by AVG anti-virus system (http://www.grisoft.com).
          Version: 6.0.594 / Virus Database: 377 - Release Date: 2/24/04


          [Non-text portions of this message have been removed]
        • Gil Lund
          David. Bad advice! Regardless of forestay lenght you can easily overtighten the shrouds long before the mast will bend enough to relive the compression load.
          Message 4 of 19 , Mar 2, 2004
          • 0 Attachment
            David.
            Bad advice!
            Regardless of forestay lenght you can easily overtighten the shrouds
            long before the mast will bend enough to relive the compression load.
            You can not only compress the deck step but also tear the chainplates
            out of the deck by overtensioning the shrouds. Max tension should be
            26 lb on the inner and 24 lb on the outer shrouds. The forestay
            lenght and mast rake has very little effect on these numbers. I set
            up my rig with the backstay and forestay loose.

            If the baby stay is loose the mast will bend or buckle backwards when
            the shrouds are tensioned. This will cause the main to become fuller,
            not flatter. To flatten the main you will have to bend the mast
            forward by loosning the lower shrouds and tightning the baby stay.
            A tension gage is definitivly a big help in setting up the rig.
            gil


            --- In SJ-24@yahoogroups.com, "Dave Brezina" <dbrezina@i...> wrote:
            > If your forestay is the right length, then my guess is you can't
            make
            > the shrouds too tight, because the mast will bend, as intended, and
            > that will give you a good, flat, mainsail shape.
            >
            > Having screwed up the forestay by overtightening to compensate for a
            > boatyard error in headfoil length (Scorpion has roller furling), I
            can
            > unequivocally say that if everything is too tight, you can compress
            > the deck causing bucking and delamination. That's bad.
            >
            > But what I don't get is how a guage would help with a normal mast
            rake
            > -- the forestay the right length. Since the mast is designed to
            bend,
            > and it can also be misaligned athwartship, wouldn't the guage reach
            an
            > equilibrium? So your port and starboard shrouds would always be the
            > same? And if the mast bends and the stay is the right length,
            > wouldn't the tension be the same in each component of the standing
            > rigging? And, of course applying backstay tension changes the whole
            > system. So, although I like gizmos, the $70 or so for each guage
            (the
            > size range didn't cover both inner and outer shrouds the last time I
            > looked) it seems to me like the investment would be better in
            > something like new shrouds, babystay, or pair of turnbuckles. Maybe
            > I'm missing something.
            >
            > Look at the group's files sections for "mast tuning" articles.
            >
            > Dave Brezina
            > Scorpion
            > Chicago
            >
            >
            >
            >
            >
            >
            > --- In SJ-24@yahoogroups.com, "Michael Sloan" <eddieaacc@y...>
            wrote:
            > > Hey folks, I'll be stepping my mast this weekend and I was
            wondering
            > > how tight (or how much tension) is too much. I am looking into
            > > picking up a tension tool, but is it worth it?
            > >
            > > Any info is more than I have now.
            > >
            > >
            > > I have my rudder off and it's about 4 feet long. (Just the
            rudder)
            > > If you want I'll take a picture and Next to a yard stick and E-
            Mail
            > > it to whoever
            > >
            > > Thanks Mike
          • Marschark, Marc
            Gil, Just curious: somewhere on the site, I got usual tenstions of 24 and 20...vs. your max tension of 26 and 24. That seems a lot of variation. Opinions?
            Message 5 of 19 , Mar 3, 2004
            • 0 Attachment
              Gil,

              Just curious: somewhere on the site, I got "usual" tenstions of 24 and
              20...vs. your "max tension" of 26 and 24. That seems a lot of variation.
              Opinions?

              Marc
              (Zafu #29)

              -----Original Message-----
              From: Gil Lund [mailto:gil@...]
              Sent: Wednesday, March 03, 2004 12:10 AM
              To: SJ-24@yahoogroups.com
              Subject: [SJ-24] Re: How tight is too tight


              David.
              Bad advice!
              Regardless of forestay lenght you can easily overtighten the shrouds
              long before the mast will bend enough to relive the compression load.
              You can not only compress the deck step but also tear the chainplates
              out of the deck by overtensioning the shrouds. Max tension should be
              26 lb on the inner and 24 lb on the outer shrouds. The forestay
              lenght and mast rake has very little effect on these numbers. I set
              up my rig with the backstay and forestay loose.

              If the baby stay is loose the mast will bend or buckle backwards when
              the shrouds are tensioned. This will cause the main to become fuller,
              not flatter. To flatten the main you will have to bend the mast
              forward by loosning the lower shrouds and tightning the baby stay.
              A tension gage is definitivly a big help in setting up the rig.
              gil


              [Non-text portions of this message have been removed]
            • Dave Brezina
              I guess I should stick to patent and copyright advice -- if you want good engineering advice, ask an engineer! In the case of Scorpion s deck, there were, I
              Message 6 of 19 , Mar 3, 2004
              • 0 Attachment
                I guess I should stick to patent and copyright advice -- if you want
                good engineering advice, ask an engineer!

                In the case of Scorpion's deck, there were, I guess, two variables. I
                did inject epoxy/filler to fill voids in the deck over last winter and
                I also shortened the forestay. I didn't tighten the shrouds any
                differently than in previous years, and the mast didn't pre-bend like
                it did in previous years. Hence I conclude in Scorpion's case my
                screwing up forestay length increased compression on the starboard
                side of the deck -- where the offcenter compression post doesn't
                provide support. I suppose on a 25 year old boat, anything could happen.

                By the way, plans for this spring involve a new extrusion for the
                furler and possibly replacing the forestay to directly correct for the
                previous boatyard's mistake. The deck has already had epoxy injected
                where it delaminated and has been jacked back into place.

                Dave Brezina
                Scorpion
                Chicago


                --- In SJ-24@yahoogroups.com, "Gil Lund" <gil@l...> wrote:
                > David.
                > Bad advice!
                > Regardless of forestay lenght you can easily overtighten the shrouds
                > long before the mast will bend enough to relive the compression load.
                > You can not only compress the deck step but also tear the chainplates
                > out of the deck by overtensioning the shrouds. Max tension should be
                > 26 lb on the inner and 24 lb on the outer shrouds. The forestay
                > lenght and mast rake has very little effect on these numbers. I set
                > up my rig with the backstay and forestay loose.
                >
                > If the baby stay is loose the mast will bend or buckle backwards when
                > the shrouds are tensioned. This will cause the main to become fuller,
                > not flatter. To flatten the main you will have to bend the mast
                > forward by loosning the lower shrouds and tightning the baby stay.
                > A tension gage is definitivly a big help in setting up the rig.
                > gil
                >
                >
                > --- In SJ-24@yahoogroups.com, "Dave Brezina" <dbrezina@i...> wrote:
                > > If your forestay is the right length, then my guess is you can't
                > make
                > > the shrouds too tight, because the mast will bend, as intended, and
                > > that will give you a good, flat, mainsail shape.
                > >
                > > Having screwed up the forestay by overtightening to compensate for a
                > > boatyard error in headfoil length (Scorpion has roller furling), I
                > can
                > > unequivocally say that if everything is too tight, you can compress
                > > the deck causing bucking and delamination. That's bad.
                > >
                > > But what I don't get is how a guage would help with a normal mast
                > rake
                > > -- the forestay the right length. Since the mast is designed to
                > bend,
                > > and it can also be misaligned athwartship, wouldn't the guage reach
                > an
                > > equilibrium? So your port and starboard shrouds would always be the
                > > same? And if the mast bends and the stay is the right length,
                > > wouldn't the tension be the same in each component of the standing
                > > rigging? And, of course applying backstay tension changes the whole
                > > system. So, although I like gizmos, the $70 or so for each guage
                > (the
                > > size range didn't cover both inner and outer shrouds the last time I
                > > looked) it seems to me like the investment would be better in
                > > something like new shrouds, babystay, or pair of turnbuckles. Maybe
                > > I'm missing something.
                > >
                > > Look at the group's files sections for "mast tuning" articles.
                > >
                > > Dave Brezina
                > > Scorpion
                > > Chicago
                > >
                > >
                > >
                > >
                > >
                > >
                > > --- In SJ-24@yahoogroups.com, "Michael Sloan" <eddieaacc@y...>
                > wrote:
                > > > Hey folks, I'll be stepping my mast this weekend and I was
                > wondering
                > > > how tight (or how much tension) is too much. I am looking into
                > > > picking up a tension tool, but is it worth it?
                > > >
                > > > Any info is more than I have now.
                > > >
                > > >
                > > > I have my rudder off and it's about 4 feet long. (Just the
                > rudder)
                > > > If you want I'll take a picture and Next to a yard stick and E-
                > Mail
                > > > it to whoever
                > > >
                > > > Thanks Mike
              • Bill Sims
                Michael, You can definitely overtension very easily and damage the boat. Specifically, you will crunch the coachroof immediately under the mast step. Back in
                Message 7 of 19 , Mar 3, 2004
                • 0 Attachment
                  Michael,

                  You can definitely overtension very easily and damage the boat. Specifically, you will crunch the coachroof immediately under the mast step.

                  Back in the late 70s tensioning Lightning class shrouds to 400 pounds was the "fast" setting. In just 4 years that setting warped my hull until it was no longer within the class allowed arcs (but nobody checked, and boat was awesomely fast....) and one of my turnbuckles stripped. Probably because this boat traveled alot and the mast was constantly going up and down. After a few years and some cracked hulls, the class ruled that max tension was 250 pounds. And that was on a 700 pound boat with much smaller standing rigging than a San Juan.

                  My tension is snug, but nowhere near as tight as I had on a Lightning. No longer have my Loos Gauge, so no idea what it really is. Would guess 50 to 75 pounds.

                  Bill Sims
                  Mandeville, Louisiana
                  www.BillSimsRealEstate.com

                  [Non-text portions of this message have been removed]
                • gc138@aol.com
                  Dave - Can you not just lengthen your forestay by means of adding a longer turnbuckle or tang or something? George #18 Spaghetti [Non-text portions of this
                  Message 8 of 19 , Mar 3, 2004
                  • 0 Attachment
                    Dave - Can you not just lengthen your forestay by means of adding a longer
                    turnbuckle or tang or something?
                    George #18 "Spaghetti"


                    [Non-text portions of this message have been removed]
                  • niels daugbjerg
                    OK guys, Time for the old rigger to weigh in on this one. Just remember that the purpose, and only purpose of the standing rigging is to keep the mast up and
                    Message 9 of 19 , Mar 3, 2004
                    • 0 Attachment
                      OK guys,
                      Time for the old rigger to weigh in on this one. Just remember that the purpose, and only purpose of the standing rigging is to keep the mast up and more importantly, to keep it in column(compression). If that tube is perfectly straight it would probably support the combined weight of a years production of SJ24's. If you are out sailing with everything flying and the mast is in column(athwartships) on both tacks and the prebend is set properly(balance of H'stay,Bstay and babystay) it is tight enough. I have been on some boats (a Hunter 54 comes to mind) that was set up so tight that none of the doors or drawers would open or close. Just for fun, when you are putting the rig up, put a tape on the boat, fore and aft, and measure again when everything is tight and she how much shorter the boat is!
                      Niels

                      gc138@... wrote:
                      Dave - Can you not just lengthen your forestay by means of adding a longer
                      turnbuckle or tang or something?
                      George #18 "Spaghetti"


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



                      ---------------------------------
                      Yahoo! Groups Links

                      To visit your group on the web, go to:
                      http://groups.yahoo.com/group/SJ-24/

                      To unsubscribe from this group, send an email to:
                      SJ-24-unsubscribe@yahoogroups.com

                      Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



                      ---------------------------------
                      Do you Yahoo!?
                      Yahoo! Search - Find what you�re looking for faster.

                      [Non-text portions of this message have been removed]
                    • niels daugbjerg
                      OK guys, Time for the old rigger to weigh in on this one. Just remember that the purpose, and only purpose of the standing rigging is to keep the mast up and
                      Message 10 of 19 , Mar 3, 2004
                      • 0 Attachment
                        OK guys,
                        Time for the old rigger to weigh in on this one. Just remember that the purpose, and only purpose of the standing rigging is to keep the mast up and more importantly, to keep it in column(compression). If that tube is perfectly straight it would probably support the combined weight of a years production of SJ24's. If you are out sailing with everything flying and the mast is in column(athwartships) on both tacks and the prebend is set properly(balance of H'stay,Bstay and babystay) it is tight enough. I have been on some boats (a Hunter 54 comes to mind) that was set up so tight that none of the doors or drawers would open or close. Just for fun, when you are putting the rig up, put a tape on the boat, fore and aft, and measure again when everything is tight and she how much shorter the boat is!
                        Niels

                        gc138@... wrote:
                        Dave - Can you not just lengthen your forestay by means of adding a longer
                        turnbuckle or tang or something?
                        George #18 "Spaghetti"


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



                        ---------------------------------
                        Yahoo! Groups Links

                        To visit your group on the web, go to:
                        http://groups.yahoo.com/group/SJ-24/

                        To unsubscribe from this group, send an email to:
                        SJ-24-unsubscribe@yahoogroups.com

                        Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



                        ---------------------------------
                        Do you Yahoo!?
                        Yahoo! Search - Find what you�re looking for faster.

                        [Non-text portions of this message have been removed]
                      • genoageorge
                        be aware of the weather helm deamons you might invite to visit your sj24 if you lengthen the fore stay.moveing the head of the mast back by lengthening the
                        Message 11 of 19 , Mar 3, 2004
                        • 0 Attachment
                          be aware of the weather helm deamons you might invite to visit your
                          sj24 if you lengthen the fore stay.moveing the head of the mast back
                          by lengthening the fore stay will cause the lift of the sail to
                          through the hull out of balance and want to head to the wind early.
                          you can loose helm and find yourself in an involentary change of tack
                          when the boat should be performing at it's best up wind. guess
                          what....i learned that the hard way trying to tune a Hunter......
                          Alex Henly hull #410 TAXI
                        • Dave Brezina
                          The problem is that the boatyard cut the extrusions for the roller furling too short. What I was trying to do when I misadjusted the forestay was to
                          Message 12 of 19 , Mar 4, 2004
                          • 0 Attachment
                            The problem is that the boatyard cut the extrusions for the roller
                            furling too short. What I was trying to do when I misadjusted the
                            forestay was to compensate for the too short foil by shortening
                            (tightening) the foil.

                            If I don't get around to replacing the aluminum extrusion for the
                            foil, which may require replacing the forestay because there isn't
                            clearance to remove slide it over the terminal at the bottom, then I
                            will adjust the forestay length back to where it should have been.

                            Dave Brezina
                            Scorpion
                            Chicago

                            --- In SJ-24@yahoogroups.com, gc138@a... wrote:
                            > Dave - Can you not just lengthen your forestay by means of adding a
                            longer
                            > turnbuckle or tang or something?
                            > George #18 "Spaghetti"
                            >
                            >
                            > [Non-text portions of this message have been removed]
                          • Dave Brezina
                            Line 4 should read (tightening) the forestay.
                            Message 13 of 19 , Mar 4, 2004
                            • 0 Attachment
                              Line 4 should read "(tightening) the forestay."


                              --- In SJ-24@yahoogroups.com, "Dave Brezina" <dbrezina@i...> wrote:
                              > The problem is that the boatyard cut the extrusions for the roller
                              > furling too short. What I was trying to do when I misadjusted the
                              > forestay was to compensate for the too short foil by shortening
                              > (tightening) the foil.
                              >
                              > If I don't get around to replacing the aluminum extrusion for the
                              > foil, which may require replacing the forestay because there isn't
                              > clearance to remove slide it over the terminal at the bottom, then I
                              > will adjust the forestay length back to where it should have been.
                              >
                              > Dave Brezina
                              > Scorpion
                              > Chicago
                              >
                              > --- In SJ-24@yahoogroups.com, gc138@a... wrote:
                              > > Dave - Can you not just lengthen your forestay by means of adding a
                              > longer
                              > > turnbuckle or tang or something?
                              > > George #18 "Spaghetti"
                              > >
                              > >
                              > > [Non-text portions of this message have been removed]
                            • niels daugbjerg
                              Dave Brezina wrote:The problem is that the boatyard cut the extrusions for the roller furling too short. What I was trying to do when
                              Message 14 of 19 , Mar 4, 2004
                              • 0 Attachment
                                Dave Brezina <dbrezina@...> wrote:The problem is that the boatyard cut the extrusions for the roller
                                furling too short. What I was trying to do when I misadjusted the
                                forestay was to compensate for the too short foil by shortening
                                (tightening) the foil.

                                If I don't get around to replacing the aluminum extrusion for the
                                foil, which may require replacing the forestay because there isn't
                                clearance to remove slide it over the terminal at the bottom, then I
                                will adjust the forestay length back to where it should have been.

                                Dave Brezina
                                Scorpion
                                Chicago

                                --- In SJ-24@yahoogroups.com, gc138@a... wrote:
                                > Dave - Can you not just lengthen your forestay by means of adding a
                                longer
                                > turnbuckle or tang or something?
                                > George #18 "Spaghetti"
                                >
                                >
                                > [Non-text portions of this message have been removed]



                                ---------------------------------
                                Yahoo! Groups Links

                                To visit your group on the web, go to:
                                http://groups.yahoo.com/group/SJ-24/

                                To unsubscribe from this group, send an email to:
                                SJ-24-unsubscribe@yahoogroups.com

                                Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



                                e,

                                Don't know what kind of system you have but if the foil is long enough for your max sail consider a toggle or two at the bottom, It will raise the drum a bit but shouldn't hurt performance. There are lots of toggle configurations so one of them should work.

                                Niels


                                ---------------------------------
                                Do you Yahoo!?
                                Yahoo! Search - Find what you�re looking for faster.

                                [Non-text portions of this message have been removed]
                              • Gil Lund
                                Mark Max tension is when I start to worry about the strength of the rig. Normal operating tension is much less than that. Note that the accuracy of a
                                Message 15 of 19 , Mar 4, 2004
                                • 0 Attachment
                                  Mark
                                  "Max tension" is when I start to worry about the strength of the rig.
                                  Normal operating tension is much less than that.
                                  Note that the accuracy of a standard tension gage is not more than 10-
                                  20%. At 24 lb that is 4.8 lb. In that perspective the differnce
                                  between 20-24 and 24-26 lb is not a lot.

                                  Note that you are not measuring the actual tension in the cable but
                                  the deflection of the cable at a given point and then relating that
                                  back to tension thru a VERY complicated formula and a set of
                                  thumbnail assumptions.

                                  You always have to "calibrate" your gage by actual sailing and
                                  testing. I use the "numbers" just to achive consistency. That is why
                                  I rearly lend anyone my gage.

                                  gil


                                  --- In SJ-24@yahoogroups.com, "Marschark, Marc" <memrtl@r...> wrote:
                                  > Gil,
                                  >
                                  > Just curious: somewhere on the site, I got "usual" tenstions of 24
                                  and
                                  > 20...vs. your "max tension" of 26 and 24. That seems a lot of
                                  variation.
                                  > Opinions?
                                  >
                                  > Marc
                                  > (Zafu #29)
                                  >
                                  > -----Original Message-----
                                  > From: Gil Lund [mailto:gil@l...]
                                  > Sent: Wednesday, March 03, 2004 12:10 AM
                                  > To: SJ-24@yahoogroups.com
                                  > Subject: [SJ-24] Re: How tight is too tight
                                  >
                                  >
                                  > David.
                                  > Bad advice!
                                  > Regardless of forestay lenght you can easily overtighten the
                                  shrouds
                                  > long before the mast will bend enough to relive the compression
                                  load.
                                  > You can not only compress the deck step but also tear the
                                  chainplates
                                  > out of the deck by overtensioning the shrouds. Max tension should
                                  be
                                  > 26 lb on the inner and 24 lb on the outer shrouds. The forestay
                                  > lenght and mast rake has very little effect on these numbers. I set
                                  > up my rig with the backstay and forestay loose.
                                  >
                                  > If the baby stay is loose the mast will bend or buckle backwards
                                  when
                                  > the shrouds are tensioned. This will cause the main to become
                                  fuller,
                                  > not flatter. To flatten the main you will have to bend the mast
                                  > forward by loosning the lower shrouds and tightning the baby stay.
                                  > A tension gage is definitivly a big help in setting up the rig.
                                  > gil
                                  >
                                  >
                                  > [Non-text portions of this message have been removed]
                                • Gil Lund
                                  George That is a good idea. The standard forestay length on a stock sj24 is about 3 inches to short for good rig balance. All competitive boat on the National
                                  Message 16 of 19 , Mar 4, 2004
                                  • 0 Attachment
                                    George
                                    That is a good idea.
                                    The standard forestay length on a stock sj24 is about 3 inches to
                                    short for good rig balance. All competitive boat on the National
                                    scene have a 3-4 inch extension piece on the forestay so we can rake
                                    the mast back quite a bit. Particularly if you sail with a 163 #1
                                    this is important. Remember going from a 170 to a 163 moves the
                                    sailplan forward and decreases weather helm. Raking the mast bak
                                    counteracts the effects of this. The smaller your genoa the more you
                                    rake the mast back.
                                    gil


                                    --- In SJ-24@yahoogroups.com, gc138@a... wrote:
                                    > Dave - Can you not just lengthen your forestay by means of adding a
                                    longer
                                    > turnbuckle or tang or something?
                                    > George #18 "Spaghetti"
                                    >
                                    >
                                    > [Non-text portions of this message have been removed]
                                  • m_kanzler@yahoo.com
                                    There should be a way to insert a shackle type device to increase the length of the forestay... a good rigger should be able to come up with something. If you
                                    Message 17 of 19 , Mar 12, 2004
                                    • 0 Attachment
                                      There should be a way to insert a shackle type device to
                                      increase the length of the forestay... a good rigger
                                      should be able to come up with something. If you add
                                      the length at the bottom then the headsail will be
                                      that much higher off the deck, which has benefits and
                                      drawbacks.

                                      The key is that the added hardware has to be strong enough,
                                      the right length, and not induce bending in the forestay
                                      (it has to be aligned correctly).

                                      --- In SJ-24@yahoogroups.com, "Dave Brezina" <dbrezina@i...> wrote:
                                      > I guess I should stick to patent and copyright advice -- if you want
                                      > good engineering advice, ask an engineer!
                                      >
                                      > In the case of Scorpion's deck, there were, I guess, two
                                      variables. I
                                      > did inject epoxy/filler to fill voids in the deck over last winter
                                      and
                                      > I also shortened the forestay. I didn't tighten the shrouds any
                                      > differently than in previous years, and the mast didn't pre-bend
                                      like
                                      > it did in previous years. Hence I conclude in Scorpion's case my
                                      > screwing up forestay length increased compression on the starboard
                                      > side of the deck -- where the offcenter compression post doesn't
                                      > provide support. I suppose on a 25 year old boat, anything could
                                      happen.
                                      >
                                      > By the way, plans for this spring involve a new extrusion for the
                                      > furler and possibly replacing the forestay to directly correct for
                                      the
                                      > previous boatyard's mistake. The deck has already had epoxy
                                      injected
                                      > where it delaminated and has been jacked back into place.
                                      >
                                      > Dave Brezina
                                      > Scorpion
                                      > Chicago
                                      >
                                      >
                                      > --- In SJ-24@yahoogroups.com, "Gil Lund" <gil@l...> wrote:
                                      > > David.
                                      > > Bad advice!
                                      > > Regardless of forestay lenght you can easily overtighten the
                                      shrouds
                                      > > long before the mast will bend enough to relive the compression
                                      load.
                                      > > You can not only compress the deck step but also tear the
                                      chainplates
                                      > > out of the deck by overtensioning the shrouds. Max tension should
                                      be
                                      > > 26 lb on the inner and 24 lb on the outer shrouds. The forestay
                                      > > lenght and mast rake has very little effect on these numbers. I
                                      set
                                      > > up my rig with the backstay and forestay loose.
                                      > >
                                      > > If the baby stay is loose the mast will bend or buckle backwards
                                      when
                                      > > the shrouds are tensioned. This will cause the main to become
                                      fuller,
                                      > > not flatter. To flatten the main you will have to bend the mast
                                      > > forward by loosning the lower shrouds and tightning the baby
                                      stay.
                                      > > A tension gage is definitivly a big help in setting up the rig.
                                      > > gil
                                      > >
                                      > >
                                      > > --- In SJ-24@yahoogroups.com, "Dave Brezina" <dbrezina@i...>
                                      wrote:
                                      > > > If your forestay is the right length, then my guess is you
                                      can't
                                      > > make
                                      > > > the shrouds too tight, because the mast will bend, as intended,
                                      and
                                      > > > that will give you a good, flat, mainsail shape.
                                      > > >
                                      > > > Having screwed up the forestay by overtightening to compensate
                                      for a
                                      > > > boatyard error in headfoil length (Scorpion has roller
                                      furling), I
                                      > > can
                                      > > > unequivocally say that if everything is too tight, you can
                                      compress
                                      > > > the deck causing bucking and delamination. That's bad.
                                      > > >
                                      > > > But what I don't get is how a guage would help with a normal
                                      mast
                                      > > rake
                                      > > > -- the forestay the right length. Since the mast is designed
                                      to
                                      > > bend,
                                      > > > and it can also be misaligned athwartship, wouldn't the guage
                                      reach
                                      > > an
                                      > > > equilibrium? So your port and starboard shrouds would always
                                      be the
                                      > > > same? And if the mast bends and the stay is the right length,
                                      > > > wouldn't the tension be the same in each component of the
                                      standing
                                      > > > rigging? And, of course applying backstay tension changes the
                                      whole
                                      > > > system. So, although I like gizmos, the $70 or so for each
                                      guage
                                      > > (the
                                      > > > size range didn't cover both inner and outer shrouds the last
                                      time I
                                      > > > looked) it seems to me like the investment would be better in
                                      > > > something like new shrouds, babystay, or pair of turnbuckles.
                                      Maybe
                                      > > > I'm missing something.
                                      > > >
                                      > > > Look at the group's files sections for "mast tuning" articles.
                                      > > >
                                      > > > Dave Brezina
                                      > > > Scorpion
                                      > > > Chicago
                                      > > >
                                      > > >
                                      > > >
                                      > > >
                                      > > >
                                      > > >
                                      > > > --- In SJ-24@yahoogroups.com, "Michael Sloan" <eddieaacc@y...>
                                      > > wrote:
                                      > > > > Hey folks, I'll be stepping my mast this weekend and I was
                                      > > wondering
                                      > > > > how tight (or how much tension) is too much. I am looking
                                      into
                                      > > > > picking up a tension tool, but is it worth it?
                                      > > > >
                                      > > > > Any info is more than I have now.
                                      > > > >
                                      > > > >
                                      > > > > I have my rudder off and it's about 4 feet long. (Just the
                                      > > rudder)
                                      > > > > If you want I'll take a picture and Next to a yard stick and
                                      E-
                                      > > Mail
                                      > > > > it to whoever
                                      > > > >
                                      > > > > Thanks Mike
                                    • Morrison, John
                                      Unless your headstay is brand new, why not just get a new one made to the right length? It s not going to cost you more than 75-100 bucks at the most.JohnM
                                      Message 18 of 19 , Mar 12, 2004
                                      • 0 Attachment
                                        Unless your headstay is brand new, why not just get a new one made to the
                                        right length? It's not going to cost you more than 75-100 bucks at the
                                        most.

                                        JohnM



                                        -----Original Message-----
                                        From: m_kanzler@... [mailto:m_kanzler@...]
                                        Sent: March 12, 2004 2:16 PM
                                        To: SJ-24@yahoogroups.com
                                        Subject: [**SPAM? - subj][**SPAM? - text][**SPAM? - bayes] [SJ-24] Re:
                                        How tight is too tight


                                        There should be a way to insert a shackle type device to
                                        increase the length of the forestay... a good rigger
                                        should be able to come up with something. If you add
                                        the length at the bottom then the headsail will be
                                        that much higher off the deck, which has benefits and
                                        drawbacks.

                                        The key is that the added hardware has to be strong enough,
                                        the right length, and not induce bending in the forestay
                                        (it has to be aligned correctly).

                                        --- In SJ-24@yahoogroups.com, "Dave Brezina" <dbrezina@i...> wrote:
                                        > I guess I should stick to patent and copyright advice -- if you want
                                        > good engineering advice, ask an engineer!
                                        >
                                        > In the case of Scorpion's deck, there were, I guess, two
                                        variables. I
                                        > did inject epoxy/filler to fill voids in the deck over last winter
                                        and
                                        > I also shortened the forestay. I didn't tighten the shrouds any
                                        > differently than in previous years, and the mast didn't pre-bend
                                        like
                                        > it did in previous years. Hence I conclude in Scorpion's case my
                                        > screwing up forestay length increased compression on the starboard
                                        > side of the deck -- where the offcenter compression post doesn't
                                        > provide support. I suppose on a 25 year old boat, anything could
                                        happen.
                                        >
                                        > By the way, plans for this spring involve a new extrusion for the
                                        > furler and possibly replacing the forestay to directly correct for
                                        the
                                        > previous boatyard's mistake. The deck has already had epoxy
                                        injected
                                        > where it delaminated and has been jacked back into place.
                                        >
                                        > Dave Brezina
                                        > Scorpion
                                        > Chicago
                                        >
                                        >
                                        > --- In SJ-24@yahoogroups.com, "Gil Lund" <gil@l...> wrote:
                                        > > David.
                                        > > Bad advice!
                                        > > Regardless of forestay lenght you can easily overtighten the
                                        shrouds
                                        > > long before the mast will bend enough to relive the compression
                                        load.
                                        > > You can not only compress the deck step but also tear the
                                        chainplates
                                        > > out of the deck by overtensioning the shrouds. Max tension should
                                        be
                                        > > 26 lb on the inner and 24 lb on the outer shrouds. The forestay
                                        > > lenght and mast rake has very little effect on these numbers. I
                                        set
                                        > > up my rig with the backstay and forestay loose.
                                        > >
                                        > > If the baby stay is loose the mast will bend or buckle backwards
                                        when
                                        > > the shrouds are tensioned. This will cause the main to become
                                        fuller,
                                        > > not flatter. To flatten the main you will have to bend the mast
                                        > > forward by loosning the lower shrouds and tightning the baby
                                        stay.
                                        > > A tension gage is definitivly a big help in setting up the rig.
                                        > > gil
                                        > >
                                        > >
                                        > > --- In SJ-24@yahoogroups.com, "Dave Brezina" <dbrezina@i...>
                                        wrote:
                                        > > > If your forestay is the right length, then my guess is you
                                        can't
                                        > > make
                                        > > > the shrouds too tight, because the mast will bend, as intended,
                                        and
                                        > > > that will give you a good, flat, mainsail shape.
                                        > > >
                                        > > > Having screwed up the forestay by overtightening to compensate
                                        for a
                                        > > > boatyard error in headfoil length (Scorpion has roller
                                        furling), I
                                        > > can
                                        > > > unequivocally say that if everything is too tight, you can
                                        compress
                                        > > > the deck causing bucking and delamination. That's bad.
                                        > > >
                                        > > > But what I don't get is how a guage would help with a normal
                                        mast
                                        > > rake
                                        > > > -- the forestay the right length. Since the mast is designed
                                        to
                                        > > bend,
                                        > > > and it can also be misaligned athwartship, wouldn't the guage
                                        reach
                                        > > an
                                        > > > equilibrium? So your port and starboard shrouds would always
                                        be the
                                        > > > same? And if the mast bends and the stay is the right length,
                                        > > > wouldn't the tension be the same in each component of the
                                        standing
                                        > > > rigging? And, of course applying backstay tension changes the
                                        whole
                                        > > > system. So, although I like gizmos, the $70 or so for each
                                        guage
                                        > > (the
                                        > > > size range didn't cover both inner and outer shrouds the last
                                        time I
                                        > > > looked) it seems to me like the investment would be better in
                                        > > > something like new shrouds, babystay, or pair of turnbuckles.
                                        Maybe
                                        > > > I'm missing something.
                                        > > >
                                        > > > Look at the group's files sections for "mast tuning" articles.
                                        > > >
                                        > > > Dave Brezina
                                        > > > Scorpion
                                        > > > Chicago
                                        > > >
                                        > > >
                                        > > >
                                        > > >
                                        > > >
                                        > > >
                                        > > > --- In SJ-24@yahoogroups.com, "Michael Sloan" <eddieaacc@y...>
                                        > > wrote:
                                        > > > > Hey folks, I'll be stepping my mast this weekend and I was
                                        > > wondering
                                        > > > > how tight (or how much tension) is too much. I am looking
                                        into
                                        > > > > picking up a tension tool, but is it worth it?
                                        > > > >
                                        > > > > Any info is more than I have now.
                                        > > > >
                                        > > > >
                                        > > > > I have my rudder off and it's about 4 feet long. (Just the
                                        > > rudder)
                                        > > > > If you want I'll take a picture and Next to a yard stick and
                                        E-
                                        > > Mail
                                        > > > > it to whoever
                                        > > > >
                                        > > > > Thanks Mike




                                        Yahoo! Groups Links
                                      • Dave Brezina
                                        Actually, I think that s related to how the foil for the furler was cut too short. The rigger measured the original pin-to-pin dimension of the original
                                        Message 19 of 19 , Mar 13, 2004
                                        • 0 Attachment
                                          Actually, I think that's related to how the foil for the furler was
                                          cut too short. The rigger measured the original pin-to-pin dimension
                                          of the original forestay, but then put two 3 1/2" (pin-to-pin) tangs
                                          at the top, to get clearance for the rotation of the foil. (The top
                                          of the Harken furler spins around the swaged end of the terminal)

                                          Then, a couple of years later, when the rigger replaced both the top
                                          foil extrusion and the forestay, he overcorrected the dimension but
                                          actually should have used a dimension 3 1/2" longer.

                                          Either that or he just screwed up. So I have a 50' tape measure to
                                          make sure it gets done right this time. I also am contemplating
                                          Norseman or Sta Lok at the bottom so I can remove and replace the
                                          extrusions without replacing the forestay if I have to do this again.

                                          Anyway, the tangs at the top work fine. Anyone who wants to
                                          "lengthen" the forestay could just do that.

                                          Dave Brezina
                                          Scorpion
                                          Chicago


                                          --- In SJ-24@yahoogroups.com, m_kanzler@y... wrote:
                                          > There should be a way to insert a shackle type device to
                                          > increase the length of the forestay... a good rigger
                                          > should be able to come up with something. If you add
                                          > the length at the bottom then the headsail will be
                                          > that much higher off the deck, which has benefits and
                                          > drawbacks.
                                          >
                                          > The key is that the added hardware has to be strong enough,
                                          > the right length, and not induce bending in the forestay
                                          > (it has to be aligned correctly).
                                          >
                                          > --- In SJ-24@yahoogroups.com, "Dave Brezina" <dbrezina@i...> wrote:
                                          > > I guess I should stick to patent and copyright advice -- if you want
                                          > > good engineering advice, ask an engineer!
                                          > >
                                          > > In the case of Scorpion's deck, there were, I guess, two
                                          > variables. I
                                          > > did inject epoxy/filler to fill voids in the deck over last winter
                                          > and
                                          > > I also shortened the forestay. I didn't tighten the shrouds any
                                          > > differently than in previous years, and the mast didn't pre-bend
                                          > like
                                          > > it did in previous years. Hence I conclude in Scorpion's case my
                                          > > screwing up forestay length increased compression on the starboard
                                          > > side of the deck -- where the offcenter compression post doesn't
                                          > > provide support. I suppose on a 25 year old boat, anything could
                                          > happen.
                                          > >
                                          > > By the way, plans for this spring involve a new extrusion for the
                                          > > furler and possibly replacing the forestay to directly correct for
                                          > the
                                          > > previous boatyard's mistake. The deck has already had epoxy
                                          > injected
                                          > > where it delaminated and has been jacked back into place.
                                          > >
                                          > > Dave Brezina
                                          > > Scorpion
                                          > > Chicago
                                          > >
                                          > >
                                          > > --- In SJ-24@yahoogroups.com, "Gil Lund" <gil@l...> wrote:
                                          > > > David.
                                          > > > Bad advice!
                                          > > > Regardless of forestay lenght you can easily overtighten the
                                          > shrouds
                                          > > > long before the mast will bend enough to relive the compression
                                          > load.
                                          > > > You can not only compress the deck step but also tear the
                                          > chainplates
                                          > > > out of the deck by overtensioning the shrouds. Max tension should
                                          > be
                                          > > > 26 lb on the inner and 24 lb on the outer shrouds. The forestay
                                          > > > lenght and mast rake has very little effect on these numbers. I
                                          > set
                                          > > > up my rig with the backstay and forestay loose.
                                          > > >
                                          > > > If the baby stay is loose the mast will bend or buckle backwards
                                          > when
                                          > > > the shrouds are tensioned. This will cause the main to become
                                          > fuller,
                                          > > > not flatter. To flatten the main you will have to bend the mast
                                          > > > forward by loosning the lower shrouds and tightning the baby
                                          > stay.
                                          > > > A tension gage is definitivly a big help in setting up the rig.
                                          > > > gil
                                          > > >
                                          > > >
                                          > > > --- In SJ-24@yahoogroups.com, "Dave Brezina" <dbrezina@i...>
                                          > wrote:
                                          > > > > If your forestay is the right length, then my guess is you
                                          > can't
                                          > > > make
                                          > > > > the shrouds too tight, because the mast will bend, as intended,
                                          > and
                                          > > > > that will give you a good, flat, mainsail shape.
                                          > > > >
                                          > > > > Having screwed up the forestay by overtightening to compensate
                                          > for a
                                          > > > > boatyard error in headfoil length (Scorpion has roller
                                          > furling), I
                                          > > > can
                                          > > > > unequivocally say that if everything is too tight, you can
                                          > compress
                                          > > > > the deck causing bucking and delamination. That's bad.
                                          > > > >
                                          > > > > But what I don't get is how a guage would help with a normal
                                          > mast
                                          > > > rake
                                          > > > > -- the forestay the right length. Since the mast is designed
                                          > to
                                          > > > bend,
                                          > > > > and it can also be misaligned athwartship, wouldn't the guage
                                          > reach
                                          > > > an
                                          > > > > equilibrium? So your port and starboard shrouds would always
                                          > be the
                                          > > > > same? And if the mast bends and the stay is the right length,
                                          > > > > wouldn't the tension be the same in each component of the
                                          > standing
                                          > > > > rigging? And, of course applying backstay tension changes the
                                          > whole
                                          > > > > system. So, although I like gizmos, the $70 or so for each
                                          > guage
                                          > > > (the
                                          > > > > size range didn't cover both inner and outer shrouds the last
                                          > time I
                                          > > > > looked) it seems to me like the investment would be better in
                                          > > > > something like new shrouds, babystay, or pair of turnbuckles.
                                          > Maybe
                                          > > > > I'm missing something.
                                          > > > >
                                          > > > > Look at the group's files sections for "mast tuning" articles.
                                          > > > >
                                          > > > > Dave Brezina
                                          > > > > Scorpion
                                          > > > > Chicago
                                          > > > >
                                          > > > >
                                          > > > >
                                          > > > >
                                          > > > >
                                          > > > >
                                          > > > > --- In SJ-24@yahoogroups.com, "Michael Sloan" <eddieaacc@y...>
                                          > > > wrote:
                                          > > > > > Hey folks, I'll be stepping my mast this weekend and I was
                                          > > > wondering
                                          > > > > > how tight (or how much tension) is too much. I am looking
                                          > into
                                          > > > > > picking up a tension tool, but is it worth it?
                                          > > > > >
                                          > > > > > Any info is more than I have now.
                                          > > > > >
                                          > > > > >
                                          > > > > > I have my rudder off and it's about 4 feet long. (Just the
                                          > > > rudder)
                                          > > > > > If you want I'll take a picture and Next to a yard stick and
                                          > E-
                                          > > > Mail
                                          > > > > > it to whoever
                                          > > > > >
                                          > > > > > Thanks Mike
                                        Your message has been successfully submitted and would be delivered to recipients shortly.