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Re: piccup pram mast broken

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  • pd_89415
    I ve wondered the same thing with my newish Piccup. I went a step farther and made the even larger sail from the Ladybug design with 2 sets of reef points.  I
    Message 1 of 27 , Jul 31, 2012
      I've wondered the same thing with my newish Piccup. I went a step farther and made the even larger sail from the Ladybug design with 2 sets of reef points.  I haven't had any issues yet though I do see a bit of flex. I tie in the first reef in any winds over about 10 mph and the second in whitecaps. My mast is to Piccup specs with the longer length and is laminated from 3 pieces of clear yellow pine.

      --- In Michalak@yahoogroups.com, "Kenneth" <kwsherwood@...> wrote:
      >
      > Peter:
      > Thanks for that validation!
      > Ken
      >
      >
      > --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@> wrote:
      > >
      > > Ken, I used the larger sail-plan and I have been out in some great blows with it without incident. ( I have snapped a couple of lee boards. ;-) ) My mast was laminated with 3 layers of 1X3 fir strapping and I am always careful to mount it such that the laminations are parallel to the forward bulk-head.
      > >
      > > Peter
      > >
      > > --- In Michalak@yahoogroups.com, "Kenneth" <kwsherwood@> wrote:
      > > >
      > > > Thanks all for the thoughts and responses.
      > > >
      > > > I did follow the plans with regard to mast taper. Those familiar with the Piccup know that its primary sail plan is 55 sq ft., but Jim now sells plans with specs for an optional enlarged sail (70 sq ft.) and lengthened mast.
      > > >
      > > > As the mast broke while on a trip to Maine, I did stop by a local lumber yard and found what looks to be a decent 2x4 from which to carve the replacement.
      > > >
      > > > I have some boats with aluminum masts of course, but I'm going to give this another try -- with some fiberglass reinforcement. A lug sail with an aluminum mast just doesn't seem right! I'll let you know if I snap another one!
      > > >
      > > > Ken
      > > >
      > > > --- In Michalak@yahoogroups.com, "Monies" <m_monies@> wrote:
      > > > >
      > > > >
      > > > >
      > > > > Mike Monies, who is currently building two Welsfords, a Lillistone and a Matt Layden has switched to using all aluminum masts and spars which he gets from Metal Warehouses, www.metalwarehouse.com and they have locations in all major cities. Mike learned to make two part masts that can be put together or taken apart to store, stow or transport to use on taller masts, single piece for smaller masts and spars. The secret is to cut wooden plugs and seal really good so they float and don't sink if they go overboard.
      > > > >
      > > > > Very light and easily modified. I can probably find the photos and the links to them, instructions for building them as well.
      > > > >
      > > > > Method was from B and B Yachts and Graham Byrnes for the Coresounds.
      > > > >
      > > > > Jackie Monies
      > > > >
      > > > >
      > > > > --- In Michalak@yahoogroups.com, Bob Cook <lifewithbob101@> wrote:
      > > > > >
      > > > > > Don't forget aluminum...flag poles are a good source. Also, for small spars and yard etc. I use the fiberglass poles the electric companies use to trim trees.  They tend to be a tad heavy but not much and they sure are strong.  You can always re-enforce them at points with a few wraps of cloth. 
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      > > > > >
      > > > > > ________________________________
      > > > > > From: daniel brown <dannyb9@>
      > > > > > To: michalak@yahoogroups.com
      > > > > > Sent: Sunday, July 29, 2012 2:38 PM
      > > > > > Subject: RE: [Michalak] Re: piccup pram mast broken
      > > > > >
      > > > > >
      > > > > > finding good spar material is like picking tomatos at the grocery store...and you are looking for the one best tomato. straight, close grain is best. spruce is good. fir is stronger but a little heavier. there are some really strong, straight pieces of 'outdoor wood' treated pine available here, yes its heavy but its very tough. they seem to use better wood for treated 'odw' i guess because they get a premium price, but i doubt if you would be breaking spars if you found a good piece.  when i shop for boat wood i go through as much material as i can and pick the best. sometimes i go home empty handed and wait for the next shipment.
      > > > > >
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      > > > > >
      > > > > > To: Michalak@yahoogroups.com
      > > > > > From: nelsarv@
      > > > > > Date: Sun, 29 Jul 2012 16:15:56 +0000
      > > > > > Subject: [Michalak] Re: piccup pram mast broken
      > > > > >
      > > > > >  
      > > > > >
      > > > > >
      > > > > >
      > > > > > Kenneth,
      > > > > > Did you taper the mast as specified in the plans? I think the taper
      > > > > > helps spread the "lever action" at the fulcrum - i.e. the mast partner-
      > > > > > and creates some flex without breaking. Like a willow does.
      > > > > > The other option is to make it a bit thicker in diameter with the same
      > > > > > relative taper. Or maybe try it with a length of aluminium tubing to
      > > > > > replace the length cut off. Have it extend above the partner. Splicing a
      > > > > > new mast bottom section calls for some careful tapering and jointing to
      > > > > > be effective.
      > > > > > Nels
      > > > > > --- In Michalak@yahoogroups.com, "Kenneth" <kwsherwood@> wrote:
      > > > > > >
      > > > > > > Enjoying my new Piccup pram. But, sailing with the larger sail plan in
      > > > > > 12+ knots, white-caps and waves building from the miles of fetch on Long
      > > > > > Lake in Maine this week, I snapped the mast.
      > > > > > >
      > > > > > > Fortunately, it broke just above the partner -- so I put in the reef
      > > > > > points, sawed the bottom of the mast off evenly, and enjoyed 2 more days
      > > > > > sailing.
      > > > > > >
      > > > > > > My question -- have others had this problem with the larger lug sail
      > > > > > on this boat? Or did I simply not choose good enough wood? I'm trying to
      > > > > > decide whether to rebuild to spec or wrap the base in fiberglass etc.
      > > > > > >
      > > > > > > I have been thinking about the fact that the sail size is increased
      > > > > > but the mast diameter is not in the plans.
      > > > > > >
      > > > > > > Ken Sherwood
      > > > > > >
      > > > > >
      > > > > > [Non-text portions of this message have been removed]
      > > > > >
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      > > > > >                        
      > > > > >
      > > > > > [Non-text portions of this message have been removed]
      > > > > >
      > > > > >
      > > > > >
      > > > > > ------------------------------------
      > > > > >
      > > > > > Yahoo! Groups Links
      > > > > >
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      > > > > > [Non-text portions of this message have been removed]
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    • Dean Herring
      Peter, some body explain to me (again) which directions one wants the the lamination go and why - you have parallel to the bulkhead - meaning NOT running for
      Message 2 of 27 , Aug 1, 2012
        Peter, some body explain to me (again) which directions one wants the the lamination go and why - you have parallel to the bulkhead - meaning NOT running for and aft. thanks - dean

        --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@...> wrote:
        >
        My mast was laminated with 3 layers of 1X3 fir strapping and I am always careful to mount it such that the laminations are parallel to the forward bulk-head.
        >
        > Peter
      • Joe T
        I suspect a weak spot in the wood at the point of greatest stress. I have built a few small masts masts and set them in a PVC mast tube that extended a few
        Message 3 of 27 , Aug 4, 2012
          I suspect a weak spot in the wood at the point of greatest stress. I have built a few small masts masts and set them in a PVC mast tube that extended a few inches above the partner. I think this helps spread out the stress point as the PVC will flex a bit. And if your wood is at all suspect then I would make it a bit larger. A good piece of Doug fir should be OK with the original specifications.

          Joe T

          --- In Michalak@yahoogroups.com, "Kenneth" <kwsherwood@...> wrote:
          >
          > Enjoying my new Piccup pram. But, sailing with the larger sail plan in 12+ knots, white-caps and waves building from the miles of fetch on Long Lake in Maine this week, I snapped the mast.
          >
          > Fortunately, it broke just above the partner -- so I put in the reef points, sawed the bottom of the mast off evenly, and enjoyed 2 more days sailing.
          >
          > My question -- have others had this problem with the larger lug sail on this boat? Or did I simply not choose good enough wood? I'm trying to decide whether to rebuild to spec or wrap the base in fiberglass etc.
          >
          > I have been thinking about the fact that the sail size is increased but the mast diameter is not in the plans.
          >
          > Ken Sherwood
          >
        • Thomas Hamernik
          It may seem counter-intuitive, but a larger sail does not necessitate a larger mast (provided the original was sized correctly in the first place).  The mast
          Message 4 of 27 , Aug 4, 2012
            It may seem counter-intuitive, but a larger sail does not necessitate a larger mast (provided the original was sized correctly in the first place).  The mast should have sufficient strength so that the leverage produced by wind force on the sail is sufficient to overturn the hull when overpowered, not result in catastrophic mast failure.  Adding a larger sail generates this overturning force with less wind, but gives better light wind performance.


            On an unstayed rig, the greatest stress occurs at the partners, as Joe T notes, and, it could be that there was a flaw in the construction.  Do you have any photos of the failure?  Perhaps we can determine the cause.  It's important for the grain to run parallel to the mast or have very little runout.  And, imperfections in the wood, such as knots, should be avoided, particularly in the region near the partners.  

            Good to hear you were able to sail on for two more days!

            TJH



            ________________________________
            From: Joe T <scsbmsjoe@...>
            To: Michalak@yahoogroups.com
            Sent: Saturday, August 4, 2012 3:34 AM
            Subject: [Michalak] Re: piccup pram mast broken


             
            I suspect a weak spot in the wood at the point of greatest stress. I have built a few small masts masts and set them in a PVC mast tube that extended a few inches above the partner. I think this helps spread out the stress point as the PVC will flex a bit. And if your wood is at all suspect then I would make it a bit larger. A good piece of Doug fir should be OK with the original specifications.

            Joe T

            --- In Michalak@yahoogroups.com, "Kenneth" <kwsherwood@...> wrote:
            >
            > Enjoying my new Piccup pram. But, sailing with the larger sail plan in 12+ knots, white-caps and waves building from the miles of fetch on Long Lake in Maine this week, I snapped the mast.
            >
            > Fortunately, it broke just above the partner -- so I put in the reef points, sawed the bottom of the mast off evenly, and enjoyed 2 more days sailing.
            >
            > My question -- have others had this problem with the larger lug sail on this boat? Or did I simply not choose good enough wood? I'm trying to decide whether to rebuild to spec or wrap the base in fiberglass etc.
            >
            > I have been thinking about the fact that the sail size is increased but the mast diameter is not in the plans.
            >
            > Ken Sherwood
            >




            [Non-text portions of this message have been removed]
          • D.G. Cassidy
            The first mast I built for my AF3 snapped about two feet above the deck on the second or third sail. It looked fine from the outside, but there was a sap
            Message 5 of 27 , Aug 4, 2012
              The first mast I built for my AF3 snapped about two feet above the deck on the second or third sail. It looked fine from the outside, but there was a sap pocket hidden inside one of the boards I used (lamination of 3). The second mast is on it's 4th season and has been through some pretty stiff winds.

              On Aug 4, 2012, at 10:50 AM, Thomas Hamernik wrote:

              > It may seem counter-intuitive, but a larger sail does not necessitate a larger mast (provided the original was sized correctly in the first place). The mast should have sufficient strength so that the leverage produced by wind force on the sail is sufficient to overturn the hull when overpowered, not result in catastrophic mast failure. Adding a larger sail generates this overturning force with less wind, but gives better light wind performance.
              >
              > On an unstayed rig, the greatest stress occurs at the partners, as Joe T notes, and, it could be that there was a flaw in the construction. Do you have any photos of the failure? Perhaps we can determine the cause. It's important for the grain to run parallel to the mast or have very little runout. And, imperfections in the wood, such as knots, should be avoided, particularly in the region near the partners.
              >
              > Good to hear you were able to sail on for two more days!
              >
              > TJH
              > ________________________________
              > From: Joe T <scsbmsjoe@...>
              > To: Michalak@yahoogroups.com
              > Sent: Saturday, August 4, 2012 3:34 AM
              > Subject: [Michalak] Re: piccup pram mast broken
              >
              > I suspect a weak spot in the wood at the point of greatest stress. I have built a few small masts masts and set them in a PVC mast tube that extended a few inches above the partner. I think this helps spread out the stress point as the PVC will flex a bit. And if your wood is at all suspect then I would make it a bit larger. A good piece of Doug fir should be OK with the original specifications.
              > Joe T
              >
              > --- In Michalak@yahoogroups.com, "Kenneth" <kwsherwood@...> wrote:
              > >
              > > Enjoying my new Piccup pram. But, sailing with the larger sail plan in 12+ knots, white-caps and waves building from the miles of fetch on Long Lake in Maine this week, I snapped the mast.
              > >
              > > Fortunately, it broke just above the partner -- so I put in the reef points, sawed the bottom of the mast off evenly, and enjoyed 2 more days sailing.
              > >
              > > My question -- have others had this problem with the larger lug sail on this boat? Or did I simply not choose good enough wood? I'm trying to decide whether to rebuild to spec or wrap the base in fiberglass etc.
              > >
              > > I have been thinking about the fact that the sail size is increased but the mast diameter is not in the plans.
              > >
              > > Ken Sherwood
              > >
              >



              [Non-text portions of this message have been removed]
            • prairiedog2332
              Dean, I notice there has been no response to this query. Not sure about others, but I for one have been scratching my head wondering if it makes any difference
              Message 6 of 27 , Aug 4, 2012
                Dean,
                I notice there has been no response to this query. Not sure about
                others, but I for one have been scratching my head wondering if it makes
                any difference which direction the laminations go?
                All I could come up with is if I have a pivot bolt hole through a mast
                that is mounted in a tabernacle, I would want the hole bored across the
                laminations and not parallel to them. But not sure if that even matters.
                The late Bud McIntosh (How To Build A Wooden Boat) wrote that with
                proper glueing and clamping the joints are stronger than the wood.
                However if you don't trust your laminating ability stay with a solid
                mast.
                His secret was lots of glue and lots of clamps. Made his own spar clamps
                from 2 short pieces of hardwood, two pieces 1/8" threaded rod with nuts
                and washers each end, with short pads between the mast boards and the
                clamps to spread the pressure evenly. Installed every ft. or so, but he
                glued all his masts using powdered water-mix Weldwood glue which I found
                surprising. He designed and built schooners up to 60 ft. or so.
                Nels

                --- In Michalak@yahoogroups.com, "Dean Herring" <dfharing@...> wrote:
                >
                > Peter, some body explain to me (again) which directions one wants the
                the lamination go and why - you have parallel to the bulkhead - meaning
                NOT running for and aft. thanks - dean
                >
                > --- In Michalak@yahoogroups.com, "peter dunphy" peterdguru@ wrote:
                > >
                > My mast was laminated with 3 layers of 1X3 fir strapping and I am
                always careful to mount it such that the laminations are parallel to the
                forward bulk-head.
                > >
                > > Peter
                >



                [Non-text portions of this message have been removed]
              • Dean Herring
                Nels - yup - about to put this question on duckworks as i m getting ready to do the rigging on my first lug sail per Mic Storer on the GIS. The mast was
                Message 7 of 27 , Aug 4, 2012
                  Nels - yup - about to put this question on duckworks as i'm getting ready to do the rigging on my first lug sail per Mic Storer on the GIS. The mast was laminated from 2 2x4 WC sandwiching a 1x4 DF all rounded and solid. we shall see - thanks, Dean

                  --- In Michalak@yahoogroups.com, "prairiedog2332" <nelsarv@...> wrote:
                  >
                  > Dean,
                  > I notice there has been no response to this query. Not sure about
                  > others, but I for one have been scratching my head wondering if it makes
                  > any difference which direction the laminations go?
                  > All I could come up with is if I have a pivot bolt hole through a mast
                  > that is mounted in a tabernacle, I would want the hole bored across the
                  > laminations and not parallel to them. But not sure if that even matters.
                  > The late Bud McIntosh (How To Build A Wooden Boat) wrote that with
                  > proper glueing and clamping the joints are stronger than the wood.
                  > However if you don't trust your laminating ability stay with a solid
                  > mast.
                  > His secret was lots of glue and lots of clamps. Made his own spar clamps
                  > from 2 short pieces of hardwood, two pieces 1/8" threaded rod with nuts
                  > and washers each end, with short pads between the mast boards and the
                  > clamps to spread the pressure evenly. Installed every ft. or so, but he
                  > glued all his masts using powdered water-mix Weldwood glue which I found
                  > surprising. He designed and built schooners up to 60 ft. or so.
                  > Nels
                  >
                  > --- In Michalak@yahoogroups.com, "Dean Herring" <dfharing@> wrote:
                  > >
                  > > Peter, some body explain to me (again) which directions one wants the
                  > the lamination go and why - you have parallel to the bulkhead - meaning
                  > NOT running for and aft. thanks - dean
                  > >
                  > > --- In Michalak@yahoogroups.com, "peter dunphy" peterdguru@ wrote:
                  > > >
                  > > My mast was laminated with 3 layers of 1X3 fir strapping and I am
                  > always careful to mount it such that the laminations are parallel to the
                  > forward bulk-head.
                  > > >
                  > > > Peter
                  > >
                  >
                  >
                  >
                  > [Non-text portions of this message have been removed]
                  >
                • peter dunphy
                  The most force is exerted on the sail and mast when reaching; so that force is parallel to the bulkhead. (When running the speed of the boat is subtracted from
                  Message 8 of 27 , Aug 8, 2012
                    The most force is exerted on the sail and mast when reaching; so that force is parallel to the bulkhead. (When running the speed of the boat is subtracted from the wind speed leaving less force on the sail and mast). So in my case I have 3 pieces of 1X3 and if you think of each as a small "I beam" lever, they are strongest when oriented so the force is applied across their 3 inch width.

                    Peter

                    --- In Michalak@yahoogroups.com, "Dean Herring" <dfharing@...> wrote:
                    >
                    > Peter, some body explain to me (again) which directions one wants the the lamination go and why - you have parallel to the bulkhead - meaning NOT running for and aft. thanks - dean
                    >
                    > --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@> wrote:
                    > >
                    > My mast was laminated with 3 layers of 1X3 fir strapping and I am always careful to mount it such that the laminations are parallel to the forward bulk-head.
                    > >
                    > > Peter
                    >
                  • peter dunphy
                    P.S. this assumes that the spruce is clear and stronger than the glue. A debatable point. I use PL premium and as great as it is, it still fails occasionally
                    Message 9 of 27 , Aug 8, 2012
                      P.S. this assumes that the spruce is clear and stronger than the glue.
                      A debatable point. I use PL premium and as great as it is, it still fails occasionally when put under constant stress, dampness and UV exposure.

                      Peter

                      --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@...> wrote:
                      >
                      > The most force is exerted on the sail and mast when reaching; so that force is parallel to the bulkhead. (When running the speed of the boat is subtracted from the wind speed leaving less force on the sail and mast). So in my case I have 3 pieces of 1X3 and if you think of each as a small "I beam" lever, they are strongest when oriented so the force is applied across their 3 inch width.
                      >
                      > Peter
                      >
                      > --- In Michalak@yahoogroups.com, "Dean Herring" <dfharing@> wrote:
                      > >
                      > > Peter, some body explain to me (again) which directions one wants the the lamination go and why - you have parallel to the bulkhead - meaning NOT running for and aft. thanks - dean
                      > >
                      > > --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@> wrote:
                      > > >
                      > > My mast was laminated with 3 layers of 1X3 fir strapping and I am always careful to mount it such that the laminations are parallel to the forward bulk-head.
                      > > >
                      > > > Peter
                      > >
                      >
                    • OnEvenKeel
                      Consider that in order for the stresses within the mast to develop, the force resulting from the wind acting on the sail must be resisted by something. That
                      Message 10 of 27 , Aug 8, 2012
                        Consider that in order for the stresses within the mast to develop, the force resulting from the wind acting on the sail must be resisted by something. That something is the boat's resistance to overturning, a combination of it's buoyancy from form stability and from its ballast. The wind force increases with wind speed until one of several things occurs, the boat heels to the point where the wind is spilled, the boat capsizes (think of a pitchpole as a capsize in the fore-aft direction), or the rig fails. It should be intuitive that the boat's resistance to pitchpoling is greater than to capsizing. And, so, with enough wind, more load can develop in the rig running than for other points of sail.

                        TJH


                        On Aug 8, 2012, at 7:57 AM, "peter dunphy" <peterdguru@...> wrote:

                        > The most force is exerted on the sail and mast when reaching; so that force is parallel to the bulkhead. (When running the speed of the boat is subtracted from the wind speed leaving less force on the sail and mast). So in my case I have 3 pieces of 1X3 and if you think of each as a small "I beam" lever, they are strongest when oriented so the force is applied across their 3 inch width.
                        >
                        > Peter
                        >
                        > --- In Michalak@yahoogroups.com, "Dean Herring" <dfharing@...> wrote:
                        > >
                        > > Peter, some body explain to me (again) which directions one wants the the lamination go and why - you have parallel to the bulkhead - meaning NOT running for and aft. thanks - dean
                        > >
                        > > --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@> wrote:
                        > > >
                        > > My mast was laminated with 3 layers of 1X3 fir strapping and I am always careful to mount it such that the laminations are parallel to the forward bulk-head.
                        > > >
                        > > > Peter
                        > >
                        >
                        >
                        >
                        >
                        >
                        >
                        >

                        [Non-text portions of this message have been removed]
                      • peter dunphy
                        P.P.S. I just read John Welsford s posting over on Duckworks forum. I bow out to greater experience. The greater force can occur when running. Peter
                        Message 11 of 27 , Aug 8, 2012
                          P.P.S. I just read John Welsford's posting over on Duckworks forum. I bow out to greater experience. The greater force can occur when running.
                          Peter

                          --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@...> wrote:
                          >
                          > P.S. this assumes that the spruce is clear and stronger than the glue.
                          > A debatable point. I use PL premium and as great as it is, it still fails occasionally when put under constant stress, dampness and UV exposure.
                          >
                          > Peter
                          >
                          > --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@> wrote:
                          > >
                          > > The most force is exerted on the sail and mast when reaching; so that force is parallel to the bulkhead. (When running the speed of the boat is subtracted from the wind speed leaving less force on the sail and mast). So in my case I have 3 pieces of 1X3 and if you think of each as a small "I beam" lever, they are strongest when oriented so the force is applied across their 3 inch width.
                          > >
                          > > Peter
                          > >
                          > > --- In Michalak@yahoogroups.com, "Dean Herring" <dfharing@> wrote:
                          > > >
                          > > > Peter, some body explain to me (again) which directions one wants the the lamination go and why - you have parallel to the bulkhead - meaning NOT running for and aft. thanks - dean
                          > > >
                          > > > --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@> wrote:
                          > > > >
                          > > > My mast was laminated with 3 layers of 1X3 fir strapping and I am always careful to mount it such that the laminations are parallel to the forward bulk-head.
                          > > > >
                          > > > > Peter
                          > > >
                          > >
                          >
                        • Dennis Marshall
                          I m told there is an old saying - Upwind, the boat can take more than the crew can; Downwind the crew can take more than the boat can.  Just thought I d throw
                          Message 12 of 27 , Aug 8, 2012
                            I'm told there is an old saying - Upwind, the boat can take more than the crew can; Downwind the crew can take more than the boat can.  Just thought I'd throw my 2 cents into the ring! 

                            Dennis




                            >________________________________
                            > From: OnEvenKeel <onevenkeel@...>
                            >To: "Michalak@yahoogroups.com" <Michalak@yahoogroups.com>
                            >Sent: Wednesday, August 8, 2012 9:35 AM
                            >Subject: Re: [Michalak] Re: piccup pram mast broken
                            >
                            >

                            >Consider that in order for the stresses within the mast to develop, the force resulting from the wind acting on the sail must be resisted by something. That something is the boat's resistance to overturning, a combination of it's buoyancy from form stability and from its ballast. The wind force increases with wind speed until one of several things occurs, the boat heels to the point where the wind is spilled, the boat capsizes (think of a pitchpole as a capsize in the fore-aft direction), or the rig fails. It should be intuitive that the boat's resistance to pitchpoling is greater than to capsizing. And, so, with enough wind, more load can develop in the rig running than for other points of sail.
                            >
                            >TJH
                            >
                            >On Aug 8, 2012, at 7:57 AM, "peter dunphy" <peterdguru@...> wrote:
                            >
                            >> The most force is exerted on the sail and mast when reaching; so that force is parallel to the bulkhead. (When running the speed of the boat is subtracted from the wind speed leaving less force on the sail and mast). So in my case I have 3 pieces of 1X3 and if you think of each as a small "I beam" lever, they are strongest when oriented so the force is applied across their 3 inch width.
                            >>
                            >> Peter
                            >>
                            >> --- In Michalak@yahoogroups.com, "Dean Herring" <dfharing@...> wrote:
                            >> >
                            >> > Peter, some body explain to me (again) which directions one wants the the lamination go and why - you have parallel to the bulkhead - meaning NOT running for and aft. thanks - dean
                            >> >
                            >> > --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@> wrote:
                            >> > >
                            >> > My mast was laminated with 3 layers of 1X3 fir strapping and I am always careful to mount it such that the laminations are parallel to the forward bulk-head.
                            >> > >
                            >> > > Peter
                            >> >
                            >>
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                          • graeme
                            Not according to Michalak. Not according to Bolger. Acording to them that s not the point of sail that an unstayed mast fails on. I think it s partly a
                            Message 13 of 27 , Aug 16, 2012
                              Not according to Michalak. Not according to Bolger. Acording to them that's not the point of sail that an unstayed mast fails on. I think it's partly a question of apparent wind - usually not much if it's off the stern, but plenty close hauled where they break.

                              The sail force is nearly all normal to the sail directed to lee when close hauled, if the boat is stiff that's a lot of sideways force on the mast especially dynamic loads in gusts. When running sails are not usually set fully square (not talking symetrical spinnakers), but even if they are the forces are reduced as mentioned above and further disipated by yaw in addition to pitch.

                              Graeme

                              --- In Michalak@yahoogroups.com, OnEvenKeel <onevenkeel@...> wrote:
                              >
                              > Consider that in order for the stresses within the mast to develop, the force resulting from the wind acting on the sail must be resisted by something. That something is the boat's resistance to overturning, a combination of it's buoyancy from form stability and from its ballast. The wind force increases with wind speed until one of several things occurs, the boat heels to the point where the wind is spilled, the boat capsizes (think of a pitchpole as a capsize in the fore-aft direction), or the rig fails. It should be intuitive that the boat's resistance to pitchpoling is greater than to capsizing. And, so, with enough wind, more load can develop in the rig running than for other points of sail.
                              >
                              > TJH
                              >
                              >
                              > On Aug 8, 2012, at 7:57 AM, "peter dunphy" <peterdguru@...> wrote:
                              >
                              > > The most force is exerted on the sail and mast when reaching; so that force is parallel to the bulkhead. (When running the speed of the boat is subtracted from the wind speed leaving less force on the sail and mast). So in my case I have 3 pieces of 1X3 and if you think of each as a small "I beam" lever, they are strongest when oriented so the force is applied across their 3 inch width.
                              > >
                              > > Peter
                              > >
                              > > --- In Michalak@yahoogroups.com, "Dean Herring" <dfharing@> wrote:
                              > > >
                              > > > Peter, some body explain to me (again) which directions one wants the the lamination go and why - you have parallel to the bulkhead - meaning NOT running for and aft. thanks - dean
                              > > >
                              > > > --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@> wrote:
                              > > > >
                              > > > My mast was laminated with 3 layers of 1X3 fir strapping and I am always careful to mount it such that the laminations are parallel to the forward bulk-head.
                              > > > >
                              > > > > Peter
                              > > >
                              > >
                              > >
                              > >
                              > >
                              > >
                              > >
                              > >
                              >
                              > [Non-text portions of this message have been removed]
                              >
                            • graeme
                              ... eg.: Ballast Calculations 3 (Robbsboat), Michalak Newsletter, 1jan05 - the last four paragraphs but one read: One last bit of info you can check with the
                              Message 14 of 27 , Aug 18, 2012
                                > Not according to Michalak. Not according to Bolger.

                                eg.: Ballast Calculations 3 (Robbsboat), Michalak Newsletter, 1jan05 -
                                the last four paragraphs but one read:

                                "One last bit of info you can check with the righting moment charts is mast strength. Here again there are lots of variables. But if the boat flips at say 600 ft lbs then there is no point in designing a mast that is good for 6000 ft lbs since the boat will have capsized long ago.

                                A free standing mast like Robbsboat will have its maximum forces at the mast partner. Here the mast partner is 8' above the mast partner, so a 42# load on the sail will create a 42x8=336 ft lb torque on the mast at the partner. 336 ft lbs is 4000 in lb. Now, the elastic stress in a beam with a square cross section is 6 x m /(bxbxb) where m is the bending torque and b is the width of the mast at that point. On Robbsboat it is supposed to be 3" thick there. So the stress there is 6 x 4000 / (3x3x3) = 24000/27=900 psi. You can look up the breaking stress of wood in different handbooks but as I recall really high class perfect wood might break at 10,000 psi. I suppose the wood I buy is a lot less, especially when knots are taken into account, but it should still be way above 900 psi.

                                Could the mast be thinner? Sure if you have paid for perfect wood. But then it might be too limber and I think free standing masts are designed more for stiffness than strength. If the spars bend too easily the sail may not set well.

                                There might be another reason to go heavy with the mast. The above analysis is looking at lateral stability. Let's say you are running downwind under a real gale. Lateral stability is no problem. Now does the problem become one of sizing the mast for fore-aft stability, that is to say does the mast break before the boat pitchpoles end over end? I used to look at it that way but one day I told my theory to Phil Bolger who simply said, "Mast never fail that way. They always fail when close hauled." So I stopped thinking about it."

                                Then comes the last paragraph. I don't think so, but is it a caveat of some kind?

                                "By the way, guyed masts are totally different animals than free standing masts. The wires pull down on the mast in tension. That creates compression in the mast and it will fail as a buckling column. I've seen it happen as I watched (to somebody else). Perhaps that is what Phil was thinking about."

                                Graeme



                                --- In Michalak@yahoogroups.com, "graeme" <graeme19121984@...> wrote:
                                >
                                >
                                >
                                > Not according to Michalak. Not according to Bolger. Acording to them that's not the point of sail that an unstayed mast fails on. I think it's partly a question of apparent wind - usually not much if it's off the stern, but plenty close hauled where they break.
                                >
                                > The sail force is nearly all normal to the sail directed to lee when close hauled, if the boat is stiff that's a lot of sideways force on the mast especially dynamic loads in gusts. When running sails are not usually set fully square (not talking symetrical spinnakers), but even if they are the forces are reduced as mentioned above and further disipated by yaw in addition to pitch.
                                >
                                > Graeme
                                >
                                > --- In Michalak@yahoogroups.com, OnEvenKeel <onevenkeel@> wrote:
                                > >
                                > > Consider that in order for the stresses within the mast to develop, the force resulting from the wind acting on the sail must be resisted by something. That something is the boat's resistance to overturning, a combination of it's buoyancy from form stability and from its ballast. The wind force increases with wind speed until one of several things occurs, the boat heels to the point where the wind is spilled, the boat capsizes (think of a pitchpole as a capsize in the fore-aft direction), or the rig fails. It should be intuitive that the boat's resistance to pitchpoling is greater than to capsizing. And, so, with enough wind, more load can develop in the rig running than for other points of sail.
                                > >
                                > > TJH

                                > > On Aug 8, 2012, at 7:57 AM, "peter dunphy" <peterdguru@> wrote:
                                > >
                                > > > The most force is exerted on the sail and mast when reaching; so that force is parallel to the bulkhead. (When running the speed of the boat is subtracted from the wind speed leaving less force on the sail and mast). So in my case I have 3 pieces of 1X3 and if you think of each as a small "I beam" lever, they are strongest when oriented so the force is applied across their 3 inch width.
                                > > >
                                > > > Peter
                                > > >
                                > > > --- In Michalak@yahoogroups.com, "Dean Herring" <dfharing@> wrote:
                                > > > >
                                > > > > Peter, some body explain to me (again) which directions one wants the the lamination go and why - you have parallel to the bulkhead - meaning NOT running for and aft. thanks - dean
                                > > > >
                                > > > > --- In Michalak@yahoogroups.com, "peter dunphy" <peterdguru@> wrote:
                                > > > > >
                                > > > > My mast was laminated with 3 layers of 1X3 fir strapping and I am always careful to mount it such that the laminations are parallel to the forward bulk-head.
                                > > > > >
                                > > > > > Peter
                              • Mike
                                Ken, I was curious about what you decided to do regarding the mast after all the feedback. I am going with the larger sailplan and leeboard and using your
                                Message 15 of 27 , Sep 15, 2012
                                  Ken,
                                  I was curious about what you decided to do regarding the mast after all the feedback. I am going with the larger sailplan and leeboard and using your experience as a guide line.I'm ready to put the fiberglass cloth on my piccup. I went with the 10 ounce cloth that others had suggested because the Sureply underlayment I used is slightly thinner then the 1/4 plywood thickness. I was looking at your build photos and was wondering did you use one piece of continuous cloth to cover the bottom , bilge panels and about 4 inches up on the side panel? Or did you use several smaller width pieces because it was easier to work with.

                                  Regards,
                                  Mike
                                  --- In Michalak@yahoogroups.com, "Kenneth" <kwsherwood@...> wrote:
                                  >
                                  > Enjoying my new Piccup pram. But, sailing with the larger sail plan in 12+ knots, white-caps and waves building from the miles of fetch on Long Lake in Maine this week, I snapped the mast.
                                  >
                                  > Fortunately, it broke just above the partner -- so I put in the reef points, sawed the bottom of the mast off evenly, and enjoyed 2 more days sailing.
                                  >
                                  > My question -- have others had this problem with the larger lug sail on this boat? Or did I simply not choose good enough wood? I'm trying to decide whether to rebuild to spec or wrap the base in fiberglass etc.
                                  >
                                  > I have been thinking about the fact that the sail size is increased but the mast diameter is not in the plans.
                                  >
                                  > Ken Sherwood
                                  >
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