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

[Steve]

Rik
Well, this is my reason, 3 of us got slugs on our
mainsail a little over three years ago.  2 of us (me
included) had Rooke Sail put them on & they didn't
have one on the headboard.  The other one send off to
a sail loft for a cheaper price & his had one on the
headboard.  Ours worked fine; his - dammed thing
wouldn't go up the mast.  All three of us tried
everything we could think of to get it to work; then I
notice that we didn't have the slug on our 2. We cut
it off his and it worked.  I know, its not the
greatest reason in the world, but it work & I sure was
tried of trying to figure out what was wrong.  
Steve


  
--- Rik Sandberg <sanderico at earthlink.net> wrote:
> 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?
> > > 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?
> >www.rhodes22.org/list
> >
> >
> >__________________________________
> >Do you Yahoo!?
> >Yahoo! Mail - More reliable, more storage, less
> spam
> >http://mail.yahoo.com
> >__________________________________________________
> >Use Rhodes22-list at rhodes22.org, Help?
> www.rhodes22.org/list
> 
> __________________________________________________
> Use Rhodes22-list at rhodes22.org, Help?
www.rhodes22.org/list


__________________________________
Do you Yahoo!?
Yahoo! Mail - More reliable, more storage, less spam
http://mail.yahoo.com