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

[Lloyd Crowther]

Steve,

I think you hit the nail on the head.  I considered cutting that one off but
I figured those guys were being paid for what they know while I was just a
flunky.
They certainly wouldn't suggest that as a solution because they put in on.

Besides by that time, and it embarrasses me to admit it, I was so POed and
so eager to go sailing that my thinking was even more diminished than it
usually is.

Lloyd

----- Original Message ----- 
From: "Steve" <rhodes2282 at yahoo.com>
To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
Sent: Friday, March 19, 2004 2:49 PM
Subject: Re: [Rhodes22-list] Mainsail slugs (was Mast Crane) (was Lou Moore)


> 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?
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> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > __________________________________________________
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> > Help?
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> > > > > > > > > >
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> > Help? www.rhodes22.org/list
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> > > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > __________________________________________________
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