[Rhodes22-list] Mainsail slugs (was Mast Crane) (was Lou
Moore)
Steve Alm
salm at mn.rr.com
Sat Mar 20 04:30:03 EST 2004
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?
>>>>>>>
>>>>>>> www.rhodes22.org/list
>>>>>>>
>>>>>>>
>>>>>>> __________________________________________________
>>>>>>>
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>>>>>>> www.rhodes22.org/list
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> __________________________________________________
>>>>>>>
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>>>>>>>
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>>>>>>>
>>>>>>>
>>>>>>> __________________________________________________
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