[Rhodes22-list] Mainsail slugs (was Mast Crane) (was Lou Moore)

Rik Sandberg sanderico at earthlink.net
Sat Mar 20 05:07:19 EST 2004 

Hi Slim,

Weeellll, the internet was kinda quiet last night so I laid down to read a 
book about nine o'clock. You can guess how long it took before I was 
sleeping..... Right, about 4 pages. Ooops 3:30 comes and I'm up again. Not 
too smart considering the day I'm figuring on putting in today. But, oh well, 
my Momma never claimed I was smart, but she did tell me, if you're not gonna 
be smart, you gotta be tough. :-)

Rik

On Sat, Mar 20 2004 04:30 am, Steve Alm wrote:
> Hey Rik,
> What are you doing up at this hour?  I thought I was the only one.  8-)
> Slim
>
> On 3/20/04 4:16 AM, "Rik Sandberg" <sanderico at earthlink.net> wrote:
> > Roger,
> >
> > No, don't go making any special trips. :-) I appreciate the thought. By
> > the time you read this and could do anything, I'll already be a couple
> > hundred miles from my computer.
> >
> > I never gave it a lot of thought at the time, but as I remember, the top
> > two slugs (the one on the headboard & the top one on the cloth) weren't
> > all that far apart. As you say, maybe only 6 inches, give or take a bit.
> > It probably isn't going to be an issue.
> >
> > Rik
> >
> > On Sat, Mar 20 2004 12:05 am, Roger Pihlaja wrote:
> >> Rik,
> >>
> >> When I get Dynamic Equilibrium out of winter storage this year, I'll
> >> measure the distance between the top slug & the bottom of the headboard.
> >> My recollection is the distance is about 6", but I'm not sure.  If you
> >> really need that measurement ASAP, let me know & I'll make a special
> >> trip to the Midland County Fairgrounds to visit the boat.
> >>
> >> Roger Pihlaja
> >> S/V Dynamic Equilbrium
> >>
> >> ----- Original Message -----
> >> From: "Rik Sandberg" <sanderico at earthlink.net>
> >> To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
> >> Sent: Friday, March 19, 2004 8:06 PM
> >> Subject: Re: [Rhodes22-list] Mainsail slugs (was Mast Crane) (was Lou
> >> Moore)
> >>
> >>> Roger,
> >>>
> >>> Sorry, I didn't know. I've never had a standard mainsail before, on
> >>
> >> anything
> >>
> >>> bigger than my Fatty Knees (no headboard).
> >>>
> >>> I kinda have to wonder why people who make sails wouldn't know this.
> >>> Seems like Steve said that a sailmaker had made his friend's sail. My
> >>> Flicka
> >>
> >> came
> >>
> >>> to me with this slug on the headboard. I never liked the way it looked,
> >>
> >> but
> >>
> >>> it was there and I kinda had to assume that the sailmaker who put it
> >>> there must have known something.
> >>>
> >>> I know better now. But, that still doesn't answer the question, how far
> >>
> >> below
> >>
> >>> the headboard should the top slug be?
> >>>
> >>> Sometimes I'm tempted to just go back to using the boltrope.
> >>>
> >>> Rik
> >>>
> >>> On Fri, Mar 19 2004 05:39 pm, Roger Pihlaja wrote:
> >>>> Oh brother, problem solved!  The reason you don't put a slug on the
> >>>> headboard is that the headboard is rigid.  The system needs the slight
> >>
> >> flex
> >>
> >>>> of the cloth sails in order not to bind up as the length of halyard is
> >>>> reduced as the mainsail is hoisted up the mast.  It's sort of the
> >>>> "universal joint" in the system & putting a slug on the headboard took
> >>
> >> all
> >>
> >>>> the flexibility out.  Never put a slug on the headboard.
> >>>>
> >>>> Roger Pihlaja
> >>>> S/V Dynamic Equilibrium
> >>>>
> >>>> ----- Original Message -----
> >>>> From: "Rik Sandberg" <sanderico at earthlink.net>
> >>>> To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
> >>>> Sent: Friday, March 19, 2004 4:34 PM
> >>>> Subject: Re: [Rhodes22-list] Mainsail slugs (was Mast Crane) (was Lou
> >>>> Moore)
> >>>>
> >>>>> Steve,
> >>>>>
> >>>>> Hmmm....don't need a slug on the headboard.....I too had (key word
> >>
> >> had) a
> >>
> >>>>> slug on the headboard of the mainsail on my Flicka. It wore out and
> >>
> >> broke
> >>
> >>>>> when we were down at Kentucky Lake last fall. the other slugs seem to
> >>
> >> be
> >>
> >>>>> fine. I was wondering how to go about replacing it, but if this is
> >>
> >> right,
> >>
> >>>> I
> >>>>
> >>>>> shouldn't have to.
> >>>>>
> >>>>> Can you explain why a slug isn't needed on the headboard?? It seems
> >>>>
> >>>> there's
> >>>>
> >>>>> a lot of new stuff to learn when you go from a IMF main to a standard
> >>>>> main
> >>>>>
> >>>> :-)
> >>>>>
> >>>>> Rik
> >>>>>
> >>>>> At 01:49 PM 3/19/2004, you wrote:
> >>>>>> Lloyd
> >>>>>> The slug in the headboard was the problem.  Didn't
> >>>>>> need one there.
> >>>>>> Steve
> >>>>>>
> >>>>>> --- Lloyd Crowther <lcrowther at cox.net> wrote:
> >>>>>>> Roger,
> >>>>>>>
> >>>>>>> Thanks for the prompt reply.  My problem was more
> >>>>>>> that I couldn't get my
> >>>>>>> Main all the way up rather than I couldn't get it
> >>>>>>> down.  Before I had the
> >>>>>>> 7/16" plastic, cylindrical slugs sewn onto grommets
> >>>>>>> the sail maker later
> >>>>>>> placed aft of the bolt rope along the mainsail's
> >>>>>>> luff, I tied a slug to my
> >>>>>>> halyard, tied a string to the lower part of the slot
> >>>>>>> on the slug to pull the
> >>>>>>> slug back down, and hoisted it up, no problem.  I
> >>>>>>> took the sail to Quantum
> >>>>>>> Sails Loft in Annapolis and asked them to put the
> >>>>>>> slugs on.  When I tried to
> >>>>>>> raise the sail, the topmost slug would bind about
> >>>>>>> 3/4 t0 7/8 of the way to
> >>>>>>> the masthead no matter what I did, lubrication or
> >>>>>>> any thing else. I never
> >>>>>>> had any problem getting the sail back down because I
> >>>>>>> did all this in my
> >>>>>>> slip.  I did take the precaution of looping a light
> >>>>>>> line through the bottoms
> >>>>>>> of the slug slots so if they twisted I could pull on
> >>>>>>> the line to re-tension
> >>>>>>> any slug that twisted.
> >>>>>>>
> >>>>>>> I just went down to the cellar and measured the
> >>>>>>> spacing of the grommets they
> >>>>>>> put along the luff (I cut the slugs off when I
> >>>>>>> abandoned the whole exercise
> >>>>>>> last spring) and found they were 18" on centers.  So
> >>>>>>> I guess you have solved
> >>>>>>> some if not all of my problem although I doubt that
> >>>>>>> I pay all that money
> >>>>>>> again to prove you right.
> >>>>>>>
> >>>>>>>   My thought was that as the sail got nearer the
> >>>>>>> pulley in the mast. the
> >>>>>>> halyard tended to pull the headboard, with its
> >>>>>>> sewed-on slug, in towards the
> >>>>>>> mast, relieving the pressure on that slug and
> >>>>>>> allowing it to twist and bind.
> >>>>>>> In any event, thank you again for your rapid and
> >>>>>>> responsive reply, your
> >>>>>>> knowledge continues to amaze me.
> >>>>>>>
> >>>>>>> Lloyd
> >>>>>>>
> >>>>>>> ----- Original Message -----
> >>>>>>> From: "Roger Pihlaja" <cen09402 at centurytel.net>
> >>>>>>> To: "The Rhodes 22 mail list"
> >>>>>>> <rhodes22-list at rhodes22.org>
> >>>>>>> Sent: Friday, March 19, 2004 5:45 AM
> >>>>>>> Subject: Re: [Rhodes22-list] Mast Crane (was Lou
> >>>>>>> Moore)
> >>>>>>>
> >>>>>>>> Lloyd,
> >>>>>>>>
> >>>>>>>> I used 7/16" dia. cylindrical plastic sail slugs
> >>>>>>>
> >>>>>>> on the luff and a 7/16"
> >>>>>>>
> >>>>>>>> dia. bolt rope on the foot.  Note: There are two
> >>>>>>>
> >>>>>>> styles of sail slugs in
> >>>>>>>
> >>>>>>>> common use, T-shaped & cylindrical shaped.  Each
> >>>>>>>
> >>>>>>> style is designed to be
> >>>>>>>
> >>>>>>>> used with the cooresponding slot shape on a mast
> >>>>>>>
> >>>>>>> and they are not
> >>>>>>>
> >>>>>>>> interchangable.  On Dynamic Equilibrium, the
> >>>>>>>
> >>>>>>> cylindrical style of sail
> >>>>>>> slug
> >>>>>>>
> >>>>>>>> matched the configuration of the extruded slot on
> >>>>>>>
> >>>>>>> the mast.  If a bolt
> >>>>>>> rope
> >>>>>>>
> >>>>>>>> works well in your mast slot; then, I would expect
> >>>>>>>
> >>>>>>> the cylindrical style
> >>>>>>>
> >>>>>>>> sail slugs are the correct ones for your mast as
> >>>>>>>
> >>>>>>> well.  However, I would
> >>>>>>>
> >>>>>>>> check to be certain.  7/16" dia cylindrical sail
> >>>>>>>
> >>>>>>> slugs are the same size
> >>>>>>> as
> >>>>>>>
> >>>>>>>> came on the OEM standard sail.
> >>>>>>>>
> >>>>>>>> Here's a couple of tips you might try on the mast
> >>>>>>>
> >>>>>>> groove:
> >>>>>>>> Take a rag & moisten it with a good silicone
> >>>>>>>
> >>>>>>> lubricant like Dow Corning
> >>>>>>>
> >>>>>>>> Slipicone.  Run the oily rag up & down the length
> >>>>>>>
> >>>>>>> of the slot.  The
> >>>>>>>
> >>>>>>>> Slipicone will remove any accumulated crud that's
> >>>>>>>
> >>>>>>> built up in the slot,
> >>>>>>> plus
> >>>>>>>
> >>>>>>>> it will also leave behind a silicone wax finish
> >>>>>>>
> >>>>>>> that is much more slippery
> >>>>>>>
> >>>>>>>> than the bare anodized aluminum finish.  Do the
> >>>>>>>
> >>>>>>> same thing with the
> >>>>>>> plastic
> >>>>>>>
> >>>>>>>> slugs on the mainsail.  NOTE: Dispose of this oily
> >>>>>>>
> >>>>>>> rag by immediately
> >>>>>>>
> >>>>>>>> burning it OR soak it in water, put it in a
> >>>>>>>
> >>>>>>> plastic bag, & put it out with
> >>>>>>>
> >>>>>>>> this week's trash.  NEVER just leave it sitting
> >>>>>>>
> >>>>>>> around or it may
> >>>>>>>
> >>>>>>>> spontaneously ignite & start a fire.  I usually do
> >>>>>>>
> >>>>>>> this maintenance on the
> >>>>>>>
> >>>>>>>> mast slot at the beginning of the sailing season.
> >>>>>>>>
> >>>>>>>> While you are wiping down the slot, take special
> >>>>>>>
> >>>>>>> note of the location on
> >>>>>>> the
> >>>>>>>
> >>>>>>>> mast if you feel any rough spots, dents, or burrs.
> >>>>>>>
> >>>>>>>  Go back and carefully
> >>>>>>>
> >>>>>>>> inspect those spots.  A dent or burr on the inside
> >>>>>>>
> >>>>>>> surface of the slot can
> >>>>>>>
> >>>>>>>> cause the bolt rope or sail slides to hang up.  A
> >>>>>>>
> >>>>>>> minor dent or burr can
> >>>>>>> be
> >>>>>>>
> >>>>>>>> smoothed with 400 grit emery cloth.  A rough spot
> >>>>>>>
> >>>>>>> is quite often a
> >>>>>>> build-up
> >>>>>>>
> >>>>>>>> of something like tree sap or bird droppings,
> >>>>>>>
> >>>>>>> which can be removed with a
> >>>>>>>
> >>>>>>>> product like Formula 409.  One year, I even
> >>>>>>>
> >>>>>>> discovered a mud dauber wasp
> >>>>>>>
> >>>>>>>> nest in the slot!  I was relieved to find the wasp
> >>>>>>>
> >>>>>>> nest because something
> >>>>>>>
> >>>>>>>> was absolutely jamming the mainsail at that point
> >>>>>>>
> >>>>>>> on the mast.  I was
> >>>>>>> afraid
> >>>>>>>
> >>>>>>>> it was something really serious.
> >>>>>>>>
> >>>>>>>> While you are wiping down the sail slugs, take
> >>>>>>>
> >>>>>>> note if any of them are
> >>>>>>>
> >>>>>>>> damaged or have rough spots on them.  Repair or
> >>>>>>>
> >>>>>>> replace as required.
> >>>>>>>
> >>>>>>>> After cleaning out the mast slot, take one of your
> >>>>>>>
> >>>>>>> sail slugs & run it up
> >>>>>>> &
> >>>>>>>
> >>>>>>>> down the length of the slot on the mast.  It
> >>>>>>>
> >>>>>>> should move freely with no
> >>>>>>>
> >>>>>>>> binding anywhere.  It's possible the gap width on
> >>>>>>>
> >>>>>>> the slot on your mast
> >>>>>>> has
> >>>>>>>
> >>>>>>>> a "tight spot" wherein the gap width is off spec
> >>>>>>>
> >>>>>>> too narrow.  This
> >>>>>>> condition
> >>>>>>>
> >>>>>>>> can be repaired by forcing a wooden wedge into the
> >>>>>>>
> >>>>>>> slot in the narrow
> >>>>>>> areas
> >>>>>>>
> >>>>>>>> to widen the gap.  Depending upon the length of
> >>>>>>>
> >>>>>>> the narrow slot region,
> >>>>>>> you
> >>>>>>>
> >>>>>>>> might have to custom make this wedge to fit your
> >>>>>>>
> >>>>>>> situation.
> >>>>>>>
> >>>>>>>> It's also possible that the sail slugs on the sail
> >>>>>>>
> >>>>>>> you tried were spaced
> >>>>>>> too
> >>>>>>>
> >>>>>>>> far apart.  The sail slugs need to be spaced no
> >>>>>>>
> >>>>>>> more than about 12" apart
> >>>>>>> on
> >>>>>>>
> >>>>>>>> center, or they tend to get cocked and bind up in
> >>>>>>>
> >>>>>>> the slot.  Also, the
> >>>>>>> tiny
> >>>>>>>
> >>>>>>>> shackles that attach the sail slugs to the luff on
> >>>>>>>
> >>>>>>> the mainsail must be
> >>>>>>> the
> >>>>>>>
> >>>>>>>> proper size.  If they are too short, the luff will
> >>>>>>>
> >>>>>>> bind on the trailing
> >>>>>>> edge
> >>>>>>>
> >>>>>>>> of the slot.  If they are too long, they may allow
> >>>>>>>
> >>>>>>> the sail slug to become
> >>>>>>>
> >>>>>>>> cocked in the slot & bind up.
> >>>>>>>>
> >>>>>>>> Finally, I'm sure you already know this; but, I'll
> >>>>>>>
> >>>>>>> just mention it for the
> >>>>>>>
> >>>>>>>> sake of completeness.  No mainsail will drop down
> >>>>>>>
> >>>>>>> the mast easily if the
> >>>>>>>
> >>>>>>>> sail is under load.  This means the boat must be
> >>>>>>>
> >>>>>>> head to the wind, the
> >>>>>>> boom
> >>>>>>>
> >>>>>>>> must be centered, with the boom topping lift
> >>>>>>>
> >>>>>>> supporting the weight of the
> >>>>>>>
> >>>>>>>> boom.
> >>>>>>>>
> >>>>>>>> If none of this works for you Lyoyd; then, I'm at
> >>>>>>>
> >>>>>>> a loss to explain why
> >>>>>>> your
> >>>>>>>
> >>>>>>>> mainsail won't fall down the mast when the halyard
> >>>>>>>
> >>>>>>> is released.
> >>>>>>>
> >>>>>>>> Roger Pihlaja
> >>>>>>>> S/V Dynamic Equilibrium
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> ----- Original Message -----
> >>>>>>>> From: "Lloyd Crowther" <lcrowther at cox.net>
> >>>>>>>> To: "The Rhodes 22 mail list"
> >>>>>>>
> >>>>>>> <rhodes22-list at rhodes22.org>
> >>>>>>>
> >>>>>>>> Sent: Friday, March 19, 2004 1:27 AM
> >>>>>>>> Subject: Re: [Rhodes22-list] Mast Crane (was Lou
> >>>>>>>
> >>>>>>> Moore)
> >>>>>>>
> >>>>>>>>> Roger,
> >>>>>>>>>
> >>>>>>>>> What size sail slugs do you use?  I tried 7/16"
> >>>>>>>
> >>>>>>> plastic sail slugs and
> >>>>>>>
> >>>>>>>>> couldn't even get the sail all the way up
> >>>>>>>
> >>>>>>> without it binding.  Don't
> >>>>>>> have
> >>>>>>>
> >>>>>>>>> any trouble with  raising it with the bolt rope
> >>>>>>>
> >>>>>>> but it is a bear to
> >>>>>>> furl
> >>>>>>>
> >>>>>>>> if
> >>>>>>>>
> >>>>>>>>> your a single-hander.
> >>>>>>>>>
> >>>>>>>>> Lloyd
> >>>>>>>>>
> >>>>>>>>> ----- Original Message -----
> >>>>>>>>> From: "Roger Pihlaja" <cen09402 at centurytel.net>
> >>>>>>>>> To: "The Rhodes 22 mail list"
> >>>>>>>
> >>>>>>> <rhodes22-list at rhodes22.org>
> >>>>>>>
> >>>>>>>>> Sent: Thursday, March 18, 2004 11:35 PM
> >>>>>>>>> Subject: Re: [Rhodes22-list] Mast Crane (was Lou
> >>>>>>>
> >>>>>>> Moore)
> >>>>>>>
> >>>>>>>>>> Peter,
> >>>>>>>>>>
> >>>>>>>>>> I modified the standard masthead with some
> >>>>>>>
> >>>>>>> aluminum bar stock & a MIG
> >>>>>>>
> >>>>>>>>>> welder.
> >>>>>>>>>>
> >>>>>>>>>> Look on the FAQ page for the tension settings.
> >>>>>>>>>>
> >>>>>>>>>> The way to measure maximum chord inches is to
> >>>>>>>
> >>>>>>> first load up the rig
> >>>>>>> with
> >>>>>>>
> >>>>>>>>> the
> >>>>>>>>>
> >>>>>>>>>> backstays.  Then, run the main halyard down to
> >>>>>>>
> >>>>>>> the base of the mast &
> >>>>>>>
> >>>>>>>> tie
> >>>>>>>>
> >>>>>>>>> it
> >>>>>>>>>
> >>>>>>>>>> off taut against the slot on the aft face.
> >>>>>>>
> >>>>>>> Then, using a bosun's
> >>>>>>> chair
> >>>>>>>
> >>>>>>>> or
> >>>>>>>>
> >>>>>>>>> a
> >>>>>>>>>
> >>>>>>>>>> step ladder to get up high enough on the mast,
> >>>>>>>
> >>>>>>> measure the maximum
> >>>>>>>
> >>>>>>>>>> chord-inches from the halyard to the slot on
> >>>>>>>
> >>>>>>> the mast.
> >>>>>>>
> >>>>>>>>>> Note: If all you want to do is eliminate the
> >>>>>>>
> >>>>>>> headstay sag, the
> >>>>>>> standard
> >>>>>>>
> >>>>>>>>>> backstay adjuster with the standard masthead
> >>>>>>>
> >>>>>>> geometry will do that.
> >>>>>>> The
> >>>>>>>
> >>>>>>>>>> only real reason for the crane is to create
> >>>>>>>
> >>>>>>> clearance between the
> >>>>>>>
> >>>>>>>>> backstays
> >>>>>>>>>
> >>>>>>>>>> and the big roach of a fully battened
> >>>>>>>
> >>>>>>> mainsail.  You also need to be a
> >>>>>>>
> >>>>>>>>>> little conservative re the amount of roach in
> >>>>>>>
> >>>>>>> the mainsail.  Designing
> >>>>>>>
> >>>>>>>> in
> >>>>>>>>
> >>>>>>>>>> too much roach will disrupt the balance of the
> >>>>>>>
> >>>>>>> sail plan by shifting
> >>>>>>> the
> >>>>>>>
> >>>>>>>>>> center of effort (CE) aft, thus causing an
> >>>>>>>
> >>>>>>> excessive amount of weather
> >>>>>>>
> >>>>>>>>> helm.
> >>>>>>>>>
> >>>>>>>>>> Some of this weather helm can be dialed back
> >>>>>>>
> >>>>>>> out by adjusting the
> >>>>>>> static
> >>>>>>>
> >>>>>>>>>> tilt of the mast such that the mast leans
> >>>>>>>
> >>>>>>> forward slightly, thus
> >>>>>>> moving
> >>>>>>>
> >>>>>>>>> the
> >>>>>>>>>
> >>>>>>>>>> CE of the rig forward.  The static tilt of the
> >>>>>>>
> >>>>>>> mast is adjusted with
> >>>>>>> the
> >>>>>>>
> >>>>>>>>>> turnbuckle on the forestay or by shortening
> >>>>>>>
> >>>>>>> the forestay cable.
> >>>>>>>
> >>>>>>>>>> After having installed both a high tech
> >>>>>>>
> >>>>>>> composite genoa on a Harken
> >>>>>>>
> >>>>>>>> roller
> >>>>>>>>
> >>>>>>>>>> furler & a fully battened mainsail, I'd say
> >>>>>>>
> >>>>>>> the genoa returns the
> >>>>>>>
> >>>>>>>> biggest
> >>>>>>>>
> >>>>>>>>>> performance bang for the buck.  But, the fully
> >>>>>>>
> >>>>>>> battened mainsail looks
> >>>>>>>
> >>>>>>>>>> totally cool when hoisted & the sail shape is
> >>>>>>>
> >>>>>>> much easier to adjust to
> >>>>>>>
> >>>>>>>>>> exactly what you want for the prevailing
> >>>>>>>
> >>>>>>> conditions & point of sail.
> >>>>>>>
> >>>>>>>>>> You will have a choice between sail slugs and
> >>>>>>>
> >>>>>>> a bolt rope on the luff.
> >>>>>>>
> >>>>>>>> I
> >>>>>>>>
> >>>>>>>>>> choose sail slugs & my mainsail almost falls
> >>>>>>>
> >>>>>>> down the mast when the
> >>>>>>>
> >>>>>>>>> halyard
> >>>>>>>>>
> >>>>>>>>>> is released.  Reefing it under load sometimes
> >>>>>>>
> >>>>>>> requires the sail be
> >>>>>>>
> >>>>>>>> hauled
> >>>>>>>>
> >>>>>>>>>> down; but, that was true with the partially
> >>>>>>>
> >>>>>>> battened mainsail as well.
> >>>>>>>
> >>>>>>>>> You
> >>>>>>>>>
> >>>>>>>>>> will have a choice between loose footed &
> >>>>>>>
> >>>>>>> footed using a bolt rope.  I
> >>>>>>>
> >>>>>>>>>> choose a bolt rope on the foot, mainly because
> >>>>>>>
> >>>>>>> that's what the
> >>>>>>> standard
> >>>>>>>
> >>>>>>>>>> mainsail had.  I would order the optional
> >>>>>>>
> >>>>>>> zippered shelf which will
> >>>>>>>
> >>>>>>>> allow
> >>>>>>>>
> >>>>>>>>>> you to increase the fullness of the lower 1/3
> >>>>>>>
> >>>>>>> of the mainsail shape
> >>>>>>> for
> >>>>>>>
> >>>>>>>>>> light air.  You zip up the shelf to flatten
> >>>>>>>
> >>>>>>> the mainsail shape for
> >>>>>>> heavy
> >>>>>>>
> >>>>>>>>>> air.  After you've paid the big bucks for this
> >>>>>>>
> >>>>>>> fully battened
> >>>>>>> mainsail,
> >>>>>>>
> >>>>>>>>>> definitely get a leech line & cleat.  The
> >>>>>>>
> >>>>>>> primary function of the
> >>>>>>> leech
> >>>>>>>
> >>>>>>>>> line
> >>>>>>>>>
> >>>>>>>>>> is to stop the trailing edge of the sail from
> >>>>>>>
> >>>>>>> fluttering as the air
> >>>>>>> foil
> >>>>>>>
> >>>>>>>>>> sheds its trailing vortices.  This fluttering
> >>>>>>>
> >>>>>>> subjects the sailcloth &
> >>>>>>>
> >>>>>>>>>> stitching in the leech to a lot of high
> >>>>>>>
> >>>>>>> frequency wear cycles, which
> >>>>>>> can
> >>>>>>>
> >>>>>>>>>> result in premature fatigue failure of the
> >>>>>>>
> >>>>>>> material.  You tighten the
> >>>>>>>
> >>>>>>>>> leech
> >>>>>>>>>
> >>>>>>>>>> line just enough to stop the fluttering.
> >>>>>>>
> >>>>>>> Thus, the leech line extends
> >>>>>>>
> >>>>>>>> the
> >>>>>>>>
> >>>>>>>>>> life of your expensive new sail & is well
> >>>>>>>
> >>>>>>> worth the money up front to
> >>>>>>>
> >>>>>>>> have
> >>>>>>>>
> >>>>>>>>>> it installed.  You will have to specify the
> >>>>>>>
> >>>>>>> number of reef points in
> >>>>>>>
> >>>>>>>> your
> >>>>>>>>
> >>>>>>>>>> new mainsail.  I originally ordered just 1 set
> >>>>>>>
> >>>>>>> & later had a sailmaker
> >>>>>>>
> >>>>>>>>>> retrofit a 2nd set.  The next time around, I
> >>>>>>>
> >>>>>>> will order two sets of
> >>>>>>> reef
> >>>>>>>
> >>>>>>>>>> points.  My 1st reef point reduces the
> >>>>>>>
> >>>>>>> mainsail area by 1/3 and the
> >>>>>>>
> >>>>>>>> second
> >>>>>>>>
> >>>>>>>>>> reef point by 2/3 relative to the full
> >>>>>>>
> >>>>>>> mainsail area.
> >>>>>>>
> >>>>>>>>>> Finally, this new fully battened mainsail will
> >>>>>>>
> >>>>>>> be substantially
> >>>>>>> bulkier
> >>>>>>>
> >>>>>>>>> when
> >>>>>>>>>
> >>>>>>>>>> furled on the boom vs. the standard mainsail.
> >>>>>>>
> >>>>>>> The chances are, your
> >>>>>>>
> >>>>>>>>> current
> >>>>>>>>>
> >>>>>>>>>> mainsail cover will no longer fit.  I modified
> >>>>>>>
> >>>>>>> my old mainsail cover
> >>>>>>> to
> >>>>>>>
> >>>>>>>>> fit
> >>>>>>>>>
> >>>>>>>>>> the new sail.
> >>>>>>>>>>
> >>>>>>>>>> Roger Pihlaja
> >>>>>>>>>> S/V Dynamic Equilibrium
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> ----- Original Message -----
> >>>>>>>>>> From: "Peter Thorn" <pthorn at nc.rr.com>
> >>>>>>>>>> To: "The Rhodes 22 mail list"
> >>>>>>>
> >>>>>>> <rhodes22-list at rhodes22.org>
> >>>>>>>
> >>>>>>>>>> Sent: Thursday, March 18, 2004 5:21 PM
> >>>>>>>>>> Subject: Re: [Rhodes22-list] Mast Crane (was
> >>>>>>>
> >>>>>>> Lou Moore)
> >>>>>>>
> >>>>>>>>>>> Roger,
> >>>>>>>>>>>
> >>>>>>>>>>> I certainly will try it.  It sounds great!
> >>>>>>>>>>>
> >>>>>>>>>>> Where did you acquire your 12" mast crane?
> >>>>>>>
> >>>>>>> Do you recall Loos
> >>>>>>>
> >>>>>>>> settings
> >>>>>>>>
> >>>>>>>>>> for
> >>>>>>>>>>
> >>>>>>>>>>> forwards, uppers and aft shrouds?
> >>>>>>>>>>>
> >>>>>>>>>>> With only 4 cord/inches upper mast bend, my
> >>>>>>>
> >>>>>>> guess is the greatest
> >>>>>>>
> >>>>>>>>> benefit
> >>>>>>>>>
> >>>>>>>>>> is
> >>>>>>>>>>
> >>>>>>>>>>> headsail luff sag adjustment.   If you can
> >>>>>>>
> >>>>>>> obtain enough tension to
> >>>>>>>
> >>>>>>>> keep
> >>>>>>>>
> >>>>>>>>> a
> >>>>>>>>>
> >>>>>>>>>>> 150 Genoa close to zero cord/inches in a
> >>>>>>>
> >>>>>>> blow, you must be putting
> >>>>>>>
> >>>>>>>>>> 400-500
> >>>>>>>>>>
> >>>>>>>>>>> pounds on the headstay.   R22 construction
> >>>>>>>
> >>>>>>> looks like it would take
> >>>>>>>
> >>>>>>>>> that.
> >>>>>>>>>
> >>>>>>>>>>> Stan builds 'em beefy.
> >>>>>>>>>>>
> >>>>>>>>>>> Thinking out loud - 1) built the rig first,
> >>>>>>>
> >>>>>>> 2) measure/verify the
> >>>>>>>
> >>>>>>>>>>> "reasonable mast bend" above the spreaders,
> >>>>>>>
> >>>>>>> 3) send numbers to
> >>>>>>>
> >>>>>>>>> sailmaker.
> >>>>>>>>>
> >>>>>>>>>>> Can you think of anything else?
> >>>>>>>>>>>
> >>>>>>>>>>> Best,
> >>>>>>>>>>>
> >>>>>>>>>>> PT
> >>>>>>>>>>>
> >>>>>>>>>>>> Peter,
> >>>>>>>>>>>>
> >>>>>>>>>>>> With the forestay cable buried inside of
> >>>>>>>
> >>>>>>> the roller furling foil &
> >>>>>>>
> >>>>>>>>>>>> impossible to get at with a Loo's Tension
> >>>>>>>
> >>>>>>> gage, I've never
> >>>>>>> measured
> >>>>>>>
> >>>>>>>>> the
> >>>>>>>>>
> >>>>>>>>>>>> forestay tension.  I have some calculated
> >>>>>>>
> >>>>>>> theoretical values; but,
> >>>>>>>
> >>>>>>>>> they
> >>>>>>>>>
> >>>>>>>>>>>> would only apply to my particular boat &
> >>>>>>>
> >>>>>>> masthead geometry &
> >>>>>>>
> >>>>>>>> wouldn't
> >>>>>>>>
> >>>>>>>>> be
> >>>>>>>>>
> >>>>>>>>>>> of
> >>>>>>>>>>>
> >>>>>>>>>>>> much use to anyone else.  When you refer
> >>>>>>>
> >>>>>>> to "chord-inches, I
> >>>>>>> presume
> >>>>>>>
> >>>>>>>>> you
> >>>>>>>>>
> >>>>>>>>>>>> mean the maximum perpendicular distance
> >>>>>>>
> >>>>>>> from the chord to the
> >>>>>>> radius
> >>>>>>>
> >>>>>>>>> of
> >>>>>>>>>
> >>>>>>>>>>>> curvature?  Assuming my definition of
> >>>>>>>
> >>>>>>> chord-inch agrees with
> >>>>>>> yours,
> >>>>>>>
> >>>>>>>>> with
> >>>>>>>>>
> >>>>>>>>>>> the
> >>>>>>>>>>>
> >>>>>>>>>>>> range of adjustments on Dynamic
> >>>>>>>
> >>>>>>> Equilibrium as currently
> >>>>>>> configured,
> >>>>>>>
> >>>>>>>>>> over
> >>>>>>>>>>
> >>>>>>>>>>>> the 333-5/8 inch length of the forestay, I
> >>>>>>>
> >>>>>>> can adjust the
> >>>>>>> chord-inch
> >>>>>>>
> >>>>>>>>>> value
> >>>>>>>>>>
> >>>>>>>>>>>> from nearly 0 to about 6 inches.  The
> >>>>>>>
> >>>>>>> aluminum extrusions on the
> >>>>>>>
> >>>>>>>>>> headsail
> >>>>>>>>>>
> >>>>>>>>>>>> foils won't sag too much more than that
> >>>>>>>
> >>>>>>> without causing bearing
> >>>>>>> and
> >>>>>>>
> >>>>>>>>>>> furling
> >>>>>>>>>>>
> >>>>>>>>>>>> problems.
> >>>>>>>>>>>>
> >>>>>>>>>>>> On my current fully battened mainsail, I
> >>>>>>>
> >>>>>>> went fairly conservative
> >>>>>>> on
> >>>>>>>
> >>>>>>>>> the
> >>>>>>>>>
> >>>>>>>>>>>> amount of mast bend the mainsail can
> >>>>>>>
> >>>>>>> respond to.  It is currently
> >>>>>>>
> >>>>>>>> cut
> >>>>>>>>
> >>>>>>>>> to
> >>>>>>>>>
> >>>>>>>>>>>> respond to only about 2 chord-inches,
> >>>>>>>
> >>>>>>> mostly above the spreaders.
> >>>>>>>
> >>>>>>>> The
> >>>>>>>>
> >>>>>>>>>>> mast
> >>>>>>>>>>>
> >>>>>>>>>>>> curvature actually trails off
> >>>>>>>
> >>>>>>> asymptotically to 0 below the
> >>>>>>>
> >>>>>>>> spreaders
> >>>>>>>>
> >>>>>>>>>>>> because of stretch in the lower sides
> >>>>>>>
> >>>>>>> stays and the differential
> >>>>>>>
> >>>>>>>>>> fore/aft
> >>>>>>>>>>
> >>>>>>>>>>>> static load I put on the lower side stays.
> >>>>>>>
> >>>>>>>  The forward lower side
> >>>>>>>
> >>>>>>>>> stays
> >>>>>>>>>
> >>>>>>>>>>> are
> >>>>>>>>>>>
> >>>>>>>>>>>> adjusted tighter than the rear lower side
> >>>>>>>
> >>>>>>> stays to facilitate mast
> >>>>>>>
> >>>>>>>>>>> bending.
> >>>>>>>>>>>
> >>>>>>>>>>>> I think the amount of mast bend could be
> >>>>>>>
> >>>>>>> increased to about 4
> >>>>>>>
> >>>>>>>>>> cord-inches
> >>>>>>>>>>
> >>>>>>>>>>>> without any trouble.  When the time comes
> >>>>>>>
> >>>>>>> to replace this
> >>>>>>> mainsail,
> >>>>>>>
> >>>>>>>>>> that's
> >>>>>>>>>>
> >>>>>>>>>>>> the spec I plan to ask for.  With the
> >>>>>>>
> >>>>>>> current aluminum mast
> >>>>>>>
> >>>>>>>> extrusion,
> >>>>>>>>
> >>>>>>>>>>>> trying for more bend than about 4
> >>>>>>>
> >>>>>>> cord-inches is asking for
> >>>>>>> trouble
> >>>>>>>
> >>>>>>>> in
> >>>>>>>>
> >>>>>>>>>> my
> >>>>>>>>>>
> >>>>>>>>>>>> engineering judgement.  The aluminum
> >>>>>>>
> >>>>>>> extrusion might experience
> >>>>>>>
> >>>>>>>>> fatigue
> >>>>>>>>>
> >>>>>>>>>>>> failure (especially in a salt water
> >>>>>>>
> >>>>>>> environment) and the loads on
> >>>>>>>
> >>>>>>>> the
> >>>>>>>>
> >>>>>>>>>>>> forestay & backstays would start to get a
> >>>>>>>
> >>>>>>> little high for the hull
> >>>>>>>
> >>>>>>>>>>> structure
> >>>>>>>>>>>
> >>>>>>>>>>>> and chain plates.
> >>>>>>>>>>>>
> >>>>>>>>>>>> As you probably already know, you bend the
> >>>>>>>
> >>>>>>> mast to straighten the
> >>>>>>>
> >>>>>>>>>>> forestay,
> >>>>>>>>>>>
> >>>>>>>>>>>> thereby reducing headstay sag plus flatten
> >>>>>>>
> >>>>>>> the mainsail shape.
> >>>>>>> Both
> >>>>>>>
> >>>>>>>>>>> actions
> >>>>>>>>>>>
> >>>>>>>>>>>> depower the rig for heavy air.  Yes,
> >>>>>>>
> >>>>>>> depowering the rig with the
> >>>>>>>
> >>>>>>>>>> backstay
> >>>>>>>>>>
> >>>>>>>>>>>> adjuster is much faster than any other
> >>>>>>>
> >>>>>>> method because it takes
> >>>>>>> care
> >>>>>>>
> >>>>>>>> of
> >>>>>>>>
> >>>>>>>>>>> both
> >>>>>>>>>>>
> >>>>>>>>>>>> sails at the same time.  I have my
> >>>>>>>
> >>>>>>> backstay adjuster setup with a
> >>>>>>>
> >>>>>>>>> Harken
> >>>>>>>>>
> >>>>>>>>>>> 144
> >>>>>>>>>>>
> >>>>>>>>>>>> swivel cam base with 150 cam-matic cleat,
> >>>>>>>
> >>>>>>> 082 single bullet block,
> >>>>>>> &
> >>>>>>>
> >>>>>>>>> 071
> >>>>>>>>>
> >>>>>>>>>>>> stand-up spring mounted on the aft
> >>>>>>>
> >>>>>>> starboard gunnel.  The
> >>>>>>> swiveling
> >>>>>>>
> >>>>>>>>> arm
> >>>>>>>>>
> >>>>>>>>>>> cam
> >>>>>>>>>>>
> >>>>>>>>>>>> base & cam-matic cleat on the end of the
> >>>>>>>
> >>>>>>> arm allows me to reach
> >>>>>>> the
> >>>>>>>
> >>>>>>>>>>> backstay
> >>>>>>>>>>>
> >>>>>>>>>>>> adjuster from virtually any helm position.
> >>>>>>>
> >>>>>>>  The backstay adjuster
> >>>>>>>
> >>>>>>>> line
> >>>>>>>>
> >>>>>>>>>> is
> >>>>>>>>>>
> >>>>>>>>>>>> marked with calibration marks for quick,
> >>>>>>>
> >>>>>>> reproducible tension
> >>>>>>>
> >>>>>>>>>> adjustments.
> >>>>>>>>>>
> >>>>>>>>>>>> I used the big Harken 144 swivel cam base
> >>>>>>>
> >>>>>>> because this unit is
> >>>>>>>
> >>>>>>>> mounted
> >>>>>>>>
> >>>>>>>>>>> right
> >>>>>>>>>>>
> >>>>>>>>>>>> by where people come aboard over the
> >>>>>>>
> >>>>>>> transom from the boarding
> >>>>>>>
> >>>>>>>> ladder.
> >>>>>>>>
> >>>>>>>>>>> The
> >>>>>>>>>>>
> >>>>>>>>>>>> 144 is sufficiently stout that you can
> >>>>>>>
> >>>>>>> stand on the swiveling arm
> >>>>>>>
> >>>>>>>>>> without
> >>>>>>>>>>
> >>>>>>>>>>>> damaging it.  I've been sailing with this
> >>>>>>>
> >>>>>>> backstay adjuster setup
> >>>>>>>
> >>>>>>>>> since
> >>>>>>>>>
> >>>>>>>>>>>> 1988.  It's been absolutely bulletproof so
> >>>>>>>
> >>>>>>> far.
> >>>>>>>
> >>>>>>>>>>>> Try it - You'll like it a whole bunch!
> >>>>>>>>>>>>
> >>>>>>>>>>>> Roger Pihlaja
> >>>>>>>>>>>> S/V Dynamic Equilibrium
> >>>>>>>>>>>>
> >>>>>>>>>>>>
> >>>>>>>>>>>> ----- Original Message -----
> >>>>>>>>>>>> From: "Peter Thorn" <pthorn at nc.rr.com>
> >>>>>>>>>>>> To: "The Rhodes 22 mail list"
> >>>>>>>
> >>>>>>> <rhodes22-list at rhodes22.org>
> >>>>>>>
> >>>>>>>>>>>> Sent: Thursday, March 18, 2004 10:44 AM
> >>>>>>>>>>>> Subject: Re: [Rhodes22-list] Mast Crane
> >>>>>>>
> >>>>>>> (was Lou Moore)
> >>>>>>>
> >>>>>>>>>>>>> Roger,
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Thanks for the detailed explanation.  I
> >>>>>>>
> >>>>>>> am the child of an ME,
> >>>>>>> but
> >>>>>>>
> >>>>>>>>> not
> >>>>>>>>>
> >>>>>>>>>>> one
> >>>>>>>>>>>
> >>>>>>>>>>>>> myself.  All my engineering is pants
> >>>>>>>
> >>>>>>> seat.  I'll add "eccentric
> >>>>>>>
> >>>>>>>>>> loading"
> >>>>>>>>>>
> >>>>>>>>>>>> to
> >>>>>>>>>>>>
> >>>>>>>>>>>>> my sailing jargon vocabulary.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> So, how much tension can you add to your
> >>>>>>>
> >>>>>>> forestay by adjusting
> >>>>>>>
> >>>>>>>> your
> >>>>>>>>
> >>>>>>>>>>>>> backstay?  Can the 12" crane actually
> >>>>>>>
> >>>>>>> put more tension on
> >>>>>>> forestay
> >>>>>>>
> >>>>>>>>>> than
> >>>>>>>>>>
> >>>>>>>>>>>> std
> >>>>>>>>>>>>
> >>>>>>>>>>>>> crane can?  We all know a light beam
> >>>>>>>
> >>>>>>> straight entry points much
> >>>>>>>
> >>>>>>>>>> better.
> >>>>>>>>>>
> >>>>>>>>>>>>> And, will your Harken furler track allow
> >>>>>>>
> >>>>>>> the forestay to sag and
> >>>>>>>
> >>>>>>>>> power
> >>>>>>>>>
> >>>>>>>>>>> up
> >>>>>>>>>>>
> >>>>>>>>>>>>> (for light air)?
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> For any boat with sail reduction
> >>>>>>>
> >>>>>>> capacity, mast bending might be
> >>>>>>> a
> >>>>>>>
> >>>>>>>>> bit
> >>>>>>>>>
> >>>>>>>>>>>>> unnecessary - but  non-the-less
> >>>>>>>
> >>>>>>> interesting.  After all, one can
> >>>>>>>
> >>>>>>>>> bend
> >>>>>>>>>
> >>>>>>>>>>> the
> >>>>>>>>>>>
> >>>>>>>>>>>>> mast probably quicker than any other
> >>>>>>>
> >>>>>>> de-powering technique.
> >>>>>>>
> >>>>>>>> During
> >>>>>>>>
> >>>>>>>>> a
> >>>>>>>>>
> >>>>>>>>>>> race
> >>>>>>>>>>>
> >>>>>>>>>>>>> it wouldn't distract from more important
> >>>>>>>
> >>>>>>> things (like paying
> >>>>>>>
> >>>>>>>>> attention
> >>>>>>>>>
> >>>>>>>>>>> to
> >>>>>>>>>>>
> >>>>>>>>>>>>> the wind) nearly as much as furling
> >>>>>>>
> >>>>>>> would.  How much mast bend
> >>>>>>>
> >>>>>>>> (say
> >>>>>>>>
> >>>>>>>>> by
> >>>>>>>>>
> >>>>>>>>>>>>> "cord/inches") can you induce in Dynamic
> >>>>>>>
> >>>>>>> Equilibrium's mast
> >>>>>>> above
> >>>>>>>
> >>>>>>>>> the
> >>>>>>>>>
> >>>>>>>>>>>>> spreaders?
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> As always, I enjoy your posts.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> PT
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> Peter,
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Michael is talking about Dynamic
> >>>>>>>
> >>>>>>> Equilibrium's masthead.  I
> >>>>>>> have
> >>>>>>>
> >>>>>>>>> my
> >>>>>>>>>
> >>>>>>>>>>>> double
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> backstay attachment point moved aft
> >>>>>>>
> >>>>>>> about 6 inches in order to
> >>>>>>>
> >>>>>>>>> allow
> >>>>>>>>>
> >>>>>>>>>>> the
> >>>>>>>>>>>
> >>>>>>>>>>>>>> double backstays to clear the roach of
> >>>>>>>
> >>>>>>> my fully battened
> >>>>>>>
> >>>>>>>> mainsail.
> >>>>>>>>
> >>>>>>>>>>>>>> Mast bend is highly dependent upon how
> >>>>>>>
> >>>>>>> you setup the tension
> >>>>>>> in
> >>>>>>>
> >>>>>>>>> the
> >>>>>>>>>
> >>>>>>>>>>>>> standing
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> rigging.  I believe there is there is
> >>>>>>>
> >>>>>>> a standing rigging
> >>>>>>> tuning
> >>>>>>>
> >>>>>>>>>>>> procedure
> >>>>>>>>>>>>
> >>>>>>>>>>>>> on
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> the FAQ page.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> However, if you modify the masthead
> >>>>>>>
> >>>>>>> geometry, like on my boat,
> >>>>>>>
> >>>>>>>> the
> >>>>>>>>
> >>>>>>>>>>> mast
> >>>>>>>>>>>
> >>>>>>>>>>>>>> operates a little bit differently than
> >>>>>>>
> >>>>>>> standard.  The mast can
> >>>>>>>
> >>>>>>>> be
> >>>>>>>>
> >>>>>>>>>>>> modeled
> >>>>>>>>>>>>
> >>>>>>>>>>>>> as
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> a column statically loaded by the
> >>>>>>>
> >>>>>>> standing rigging in
> >>>>>>>
> >>>>>>>> compression
> >>>>>>>>
> >>>>>>>>> +
> >>>>>>>>>
> >>>>>>>>>> a
> >>>>>>>>>>
> >>>>>>>>>>>>>> cantilever beam point loaded at the
> >>>>>>>
> >>>>>>> masthead.  The standard
> >>>>>>>
> >>>>>>>>> masthead
> >>>>>>>>>
> >>>>>>>>>>>>>> geometry loads the upper end of the
> >>>>>>>
> >>>>>>> mast pretty symetrically.
> >>>>>>>
> >>>>>>>>>>> However,
> >>>>>>>>>>>
> >>>>>>>>>>>>> when
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> you move the double backstay
> >>>>>>>
> >>>>>>> attachment point aft, you are
> >>>>>>>
> >>>>>>>>>> introducing
> >>>>>>>>>>
> >>>>>>>>>>> a
> >>>>>>>>>>>
> >>>>>>>>>>>>>> factor called "eccentricity" (e) into
> >>>>>>>
> >>>>>>> the column loading.
> >>>>>>>
> >>>>>>>>>> Basically,
> >>>>>>>>>>
> >>>>>>>>>>>>> think
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> of e as the amount by which the
> >>>>>>>
> >>>>>>> compression force vector is
> >>>>>>>
> >>>>>>>> moved
> >>>>>>>>
> >>>>>>>>>> off
> >>>>>>>>>>
> >>>>>>>>>>>> the
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> neutral axis of the column.  i.e. when
> >>>>>>>
> >>>>>>> e = 0, the compression
> >>>>>>>
> >>>>>>>> load
> >>>>>>>>
> >>>>>>>>>> is
> >>>>>>>>>>
> >>>>>>>>>>>>>> applied right down the neutral axis of
> >>>>>>>
> >>>>>>> the column & you have
> >>>>>>>
> >>>>>>>> pure
> >>>>>>>>
> >>>>>>>>>>> column
> >>>>>>>>>>>
> >>>>>>>>>>>>>> buckling.  As e is increased, the
> >>>>>>>
> >>>>>>> deflection of the column
> >>>>>>> under
> >>>>>>>
> >>>>>>>>> the
> >>>>>>>>>
> >>>>>>>>>>>> load
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> behaves like a combination of column
> >>>>>>>
> >>>>>>> buckling + bending of a
> >>>>>>>
> >>>>>>>>>>> cantilever
> >>>>>>>>>>>
> >>>>>>>>>>>>> beam
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> point loaded on the free end.  This
> >>>>>>>
> >>>>>>> cantilever beam bending
> >>>>>>> from
> >>>>>>>
> >>>>>>>>> the
> >>>>>>>>>
> >>>>>>>>>>>>>> eccentricity is in addition to the
> >>>>>>>
> >>>>>>> cantilever beam bending
> >>>>>>>
> >>>>>>>> induced
> >>>>>>>>
> >>>>>>>>>> by
> >>>>>>>>>>
> >>>>>>>>>>>> the
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> standing rigging.  As far as inducing
> >>>>>>>
> >>>>>>> mast bend, it's the
> >>>>>>> total
> >>>>>>>
> >>>>>>>>>>>> cantilever
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> beam deflection we are interested in
> >>>>>>>
> >>>>>>> because it's reproducible
> >>>>>>> &
> >>>>>>>
> >>>>>>>>>>>>>> controllable.  Column buckling is sort
> >>>>>>>
> >>>>>>> of an on/off
> >>>>>>> catastrophic
> >>>>>>>
> >>>>>>>>>> kind
> >>>>>>>>>>
> >>>>>>>>>>> of
> >>>>>>>>>>>
> >>>>>>>>>>>>>> failure - i.e. virtually no bend up to
> >>>>>>>
> >>>>>>> some critical load &
> >>>>>>>
> >>>>>>>> then,
> >>>>>>>>
> >>>>>>>>>> BAM!
> >>>>>>>>>>
> >>>>>>>>>>>>>> buckled mast.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> You might not think that mast bend is
> >>>>>>>
> >>>>>>> possible in a masthead
> >>>>>>>
> >>>>>>>> rig.
> >>>>>>>>
> >>>>>>>>>>>>> However,
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> you have to think about the behavior
> >>>>>>>
> >>>>>>> of the mast in a 3-D
> >>>>>>> world.
> >>>>>>>
> >>>>>>>>> As
> >>>>>>>>>
> >>>>>>>>>>> the
> >>>>>>>>>>>
> >>>>>>>>>>>>>> mast is bent, the height of the
> >>>>>>>
> >>>>>>> masthead off the deck is also
> >>>>>>>
> >>>>>>>>>> reduced.
> >>>>>>>>>>
> >>>>>>>>>>>>>> Although the forestay length attached
> >>>>>>>
> >>>>>>> to the front of the
> >>>>>>>
> >>>>>>>> masthead
> >>>>>>>>
> >>>>>>>>>>>> doesn't
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> change, because the masthead drops
> >>>>>>>
> >>>>>>> down as well as moving aft,
> >>>>>>>
> >>>>>>>> the
> >>>>>>>>
> >>>>>>>>>>> mast
> >>>>>>>>>>>
> >>>>>>>>>>>>> can
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> still assume a bent shape.  This bent
> >>>>>>>
> >>>>>>> shape can be fine tuned
> >>>>>>> by
> >>>>>>>
> >>>>>>>>>>>> adjusting
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> the tension of the 4 lower sidestays,
> >>>>>>>
> >>>>>>> which collectively
> >>>>>>>
> >>>>>>>> restrain
> >>>>>>>>
> >>>>>>>>>> the
> >>>>>>>>>>
> >>>>>>>>>>>> mast
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> from moving from side-to-side as well
> >>>>>>>
> >>>>>>> as fore-aft at about the
> >>>>>>>
> >>>>>>>>>>> midpoint.
> >>>>>>>>>>>
> >>>>>>>>>>>>>> The standard double backstay tension
> >>>>>>>
> >>>>>>> adjuster with the
> >>>>>>> standard
> >>>>>>>
> >>>>>>>>>>> masthead
> >>>>>>>>>>>
> >>>>>>>>>>>>>> geometry is also capable of bending
> >>>>>>>
> >>>>>>> the mast.  However,
> >>>>>>> because
> >>>>>>>
> >>>>>>>> e
> >>>>>>>>
> >>>>>>>>> is
> >>>>>>>>>
> >>>>>>>>>>  a
> >>>>>>>>>>
> >>>>>>>>>>>>> very
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> small value with the standard masthead
> >>>>>>>
> >>>>>>> geometry, the required
> >>>>>>>
> >>>>>>>>>> backstay
> >>>>>>>>>>
> >>>>>>>>>>>>>> tension to achieve a given amount of
> >>>>>>>
> >>>>>>> mast bend is much higher,
> >>>>>>>
> >>>>>>>>> which
> >>>>>>>>>
> >>>>>>>>>>>>>> compression loads the mast closer to
> >>>>>>>
> >>>>>>> the critical column
> >>>>>>>
> >>>>>>>> buckling
> >>>>>>>>
> >>>>>>>>>>> load.
> >>>>>>>>>>>
> >>>>>>>>>>>>>> Note, this discussion is only
> >>>>>>>
> >>>>>>> applicable for the standard rig.
> >>>>>>>
> >>>>>>>>>> Never
> >>>>>>>>>>
> >>>>>>>>>>>> bend
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> an IMF mainsail mast.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Roger Pihlaja
> >>>>>>>>>>>>>> S/V Dynamic Equilibrium
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> ----- Original Message -----
> >>>>>>>>>>>>>> From: "Peter Thorn" <pthorn at nc.rr.com>
> >>>>>>>>>>>>>> To: "The Rhodes 22 mail list"
> >>>>>>>
> >>>>>>> <rhodes22-list at rhodes22.org>
> >>>>>>>
> >>>>>>>>>>>>>> Sent: Thursday, March 18, 2004 3:27 AM
> >>>>>>>>>>>>>> Subject: [Rhodes22-list] Mast Crane
> >>>>>>>
> >>>>>>> (was Lou Moore)
> >>>>>>>
> >>>>>>>>>>>>>>> Michael et al,
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> 12" mast crane?  Very interesting
> >>>>>>>
> >>>>>>> idea..  Would the forestay
> >>>>>>>
> >>>>>>>>>> tension
> >>>>>>>>>>
> >>>>>>>>>>>>> boost
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>>> with that much leverage?  Or just
> >>>>>>>
> >>>>>>> create mastbend above the
> >>>>>>>
> >>>>>>>>>>> spreaders?
> >>>>>>>>>>>
> >>>>>>>>>>>>>> Has
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> anyone, in the life of the universe,
> >>>>>>>
> >>>>>>> ever created upper mast
> >>>>>>>
> >>>>>>>>> bend
> >>>>>>>>>
> >>>>>>>>>>> with
> >>>>>>>>>>>
> >>>>>>>>>>>> a
> >>>>>>>>>>>>
> >>>>>>>>>>>>>> std
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> rig?   (You were probably thinking
> >>>>>>>
> >>>>>>> about clearing a big
> >>>>>>>
> >>>>>>>> roach).
> >>>>>>>>
> >>>>>>>>>>>>>>> Afterthought- Does a Harken forestay
> >>>>>>>
> >>>>>>> furler have a soft
> >>>>>>> track?
> >>>>>>>
> >>>>>>>>> If
> >>>>>>>>>
> >>>>>>>>>>> its
> >>>>>>>>>>>
> >>>>>>>>>>>>>> hard
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> metal, can you somehow belly the
> >>>>>>>
> >>>>>>> Genoa entry for light air?
> >>>>>>>
> >>>>>>>>>>>>>>> PT
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> PS - Go fasts are fun, but I'd trade
> >>>>>>>
> >>>>>>> them for a favorable
> >>>>>>>
> >>>>>>>> shift.
> >>>>>>>>
> >>>>>>>>>>>>>>>> well now, I think I have to switch
> >>>>>>>
> >>>>>>> sides this year,
> >>>>>>>
> >>>>>>>>> full-batted
> >>>>>>>>>
> >>>>>>>>>>> main
> >>>>>>>>>>>
> >>>>>>>>>>>>>> sail
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> with a 12 inch crane are the way to
> >>>>>>>
> >>>>>>> go, single line
> >>>>>>>
> >>>>>>>>>>>>>>>> reefing and a soild boom vang, but
> >>>>>>>
> >>>>>>> IMF is more convent.
> >>>>>>>
> >>>>>>>>>>>>>>>> MJM
> >>>>>>>
> >>>>>>> __________________________________________________
> >>>>>>>
> >>>>>>>>>>>>>>>>> Use Rhodes22-list at rhodes22.org,
> >>>>>>>
> >>>>>>> Help?
> >>>>>>>
> >>>>>>>> www.rhodes22.org/list
> >>>>>>>
> >>>>>>> __________________________________________________
> >>>>>>>
> >>>>>>>>>>>>>>>> Use Rhodes22-list at rhodes22.org,
> >>>>>>>
> >>>>>>> Help?
> >>>>>>> www.rhodes22.org/list
> >>>>>>>
> >>>>>>>
> >>>>>>> __________________________________________________
> >>>>>>>
> >>>>>>>>>>>>>>> Use Rhodes22-list at rhodes22.org,
> >>>>>>>
> >>>>>>> Help? www.rhodes22.org/list
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> __________________________________________________
> >>>>>>>
> >>>>>>>>>>>>>> Use Rhodes22-list at rhodes22.org, Help?
> >>>>>>>
> >>>>>>> www.rhodes22.org/list
> >>>>>>>
> >>>>>>>
> >>>>>>> __________________________________________________
> >>>>>>>
> >>>>>>>>>>>>> Use Rhodes22-list at rhodes22.org, Help?
> >>>>>>>
> >>>>>>> www.rhodes22.org/list
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> __________________________________________________
> >>>>>>>
> >>>>>>>>>>>> Use Rhodes22-list at rhodes22.org, Help?
> >>>>>>>
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> >>>>>>>
> >>>>>>>
> >>>>>>> __________________________________________________
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> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> __________________________________________________
> >>>>>>>
> >>>>>>>>>> Use Rhodes22-list at rhodes22.org, Help?
> >>>>>>>
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> >>>>>>>
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> >>>>>>>
> >>>>>>>
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> >>>>>>>
> >>>>>>>>> Use Rhodes22-list at rhodes22.org, Help?
> >>>>>>>
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> >>>>>>>
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> >>>>>>>
> >>>>>>>
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