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## Re: Single Gaff Halyards

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• OK, Bruce, ... I m following you, but the halyard I have in mind, like those shown on the Mackinac boat, has two attachment points on the gaff at the nominal
Message 1 of 19 , Jul 9, 2010
OK, Bruce,

> (In my mind's eye I can imagine the forces.) The sail cloth is
> pulling on the gaff. The peak halyard is lifting up on the gaff.
> OK. But also, the luff leading edge of the sail is pulling down with
> force of the vang. Probably, the critical element is whether there is
> enough force to keep that luff edge tight. If the gaff gets long,
> and/or horizontal, the luff edge will sag unless a throat halyard is
> added to keep the leading edge of the sail taught.

I'm following you, but the halyard I have in mind, like those shown on the Mackinac boat, has two attachment points on the gaff at the nominal throat and peak locations. The line is routed from the truck block to a block at the throat, then to another sheave at the truck block, and then to the peak attachment point. Theoretically, once all slack is taken out of the hoist (the leading edge of a gaff sail, but I think it would be called the luff on a lug), the peak should continue to lift as the halyard is hauled on, until all slack is gone from the leech.

I'm still pondering Patrick's point about mast height. In a perfect system, the single halyard I've described "should" work with any resaonable height above the gaff jaws, but it also seems intuitive that more height would give better leverage and the arrangement would set better.

Jon
• On Fri, Jul 9, 2010 at 1:32 PM, adventures_in_astrophotography ... You are revealing my ignorance of sailing rig part names. In my self oriented vocabulary
Message 2 of 19 , Jul 9, 2010
On Fri, Jul 9, 2010 at 1:32 PM, adventures_in_astrophotography
<jon@...> wrote:
>
>
>
> Hi Bruce,
>
> > Doesn't the Solent lug rig (famous with the original simple
> > Birdwatcher) have a single halyard gaff? So, that makes me guess that
> > the variable is both the length of the gaff in combination with the
> > angle of the gaff. (IOW, the more vertical the angle, the longer it
> > can be sustained with a single halyard.)
>
> Actually, since the Solent lug is a "lug" rig, it has a yard, not a gaff. As far as I know, all lug sails have yards, and only gaff sails have gaffs (among sails at least). It is true, however, that some lug sails have peak halyards, such as PCB applied to control the yard of his dipping lug.
>
> Jon
>

You are revealing my ignorance of sailing rig part names. In my self
oriented vocabulary (which is likely not correct) I just looked it up
in the Oxford English Dictionary and see that a "yard" is properly
defined as:

"A wooden (or steel) spar, comparatively long and slender, slung at
its centre from, and forward of, a mast and serving to support and
extend a square sail which is bent to it."

And, the solent lug rig doesn't hang forward of the mast.

The OED defines "gaff" as: "A spar used in ships to extend the heads
of fore-and-aft sails which are not set on stays"

So, I think that says that all yards are gaffs, but not all gaffs are
yards. (Yards must extent forward of the mast?)

So, I think I am seeing the OED say that the spar at the head of the
solent lug sail should be called a gaff.

And, OED defines "lug-sail" as: "A four-cornered sail, bent upon a
yard which is slung at about one-third or one-fourth of its length
from one end, and so hangs obliquely."
• Bruce, I don t think it would be meaningful to call the Solent lug on the alternative (not simpler, rather more complicated) Birdwatcher rig a gaff of any
Message 3 of 19 , Jul 9, 2010
Bruce, I don't think it would be meaningful to call the Solent lug on the alternative (not simpler, rather more complicated) Birdwatcher rig a gaff of any sort. Any lug, I think, is notable for no attachment of luff of sail to mast. The Solent halyard brings the "yard" tight to the masthead sheave, or, if the sail is reefed, a parrel holds the yard very close to the mast, and a downhaul, tensing the luff, hauls the head of yard and sail high. Tres different from gaff. I have little experience with gaffs but geometrically it does seem that a short gaff would do fine with a single halyard placed at the right point. Some of LFH's gaffs are that short; I wonder whether he shows two halyards.(Just looked: Meadowlark and Block Island boat, with very short gaffs, show two halyards and are convincing that that's generally best.) I wouldn't want to do without the various aspects of control the two halyards of the usual gaff provide.

Mason

----- Original Message -----
Sent: Friday, July 09, 2010 11:30 AM
Subject: Re: [bolger] Single Gaff Halyards

On Fri, Jul 9, 2010 at 8:08 AM, adventures_in_astrophotography
<jon@...> wrote:
>
> Does anyone have experience with single gaff halyards, as opposed to separate peak and throat halyards? I've seen these on a few rigs, usually with relatively short gaffs, such as the 18'-8" Mackinac boat in the latest BDQ (also seen in 50 Wooden Boats). I suspect they must not work as well on longer gaffs or we'd see them more often, but I'd be interested to hear from somebody with real experience.
>
> Jon

Doesn't the Solent lug rig (famous with the original simple
Birdwatcher) have a single halyard gaff? So, that makes me guess that
the variable is both the length of the gaff in combination with the
angle of the gaff. (IOW, the more vertical the angle, the longer it
can be sustained with a single halyard.)

• I m doing some repairs on my Windsprint, and when I use the random orbital sander to fair the epoxy/fiberglass the whole boat resonates with a very loud,
Message 4 of 19 , Jul 9, 2010
I'm doing some repairs on my Windsprint, and when I use the random
orbital sander to fair the epoxy/fiberglass the whole boat resonates
with a very loud, unpleasant hum. The neighbors finally complained
today. I don't really blame them.

I can't move it indoors, as I don't have a garage or shed big enough.

Does anyone have any ideas for sound suppression?

Patrick
• try placing weights in areas your not actively working, soft weights like a folded canvas dropcloth or similar would probably work best
Message 5 of 19 , Jul 9, 2010
try placing weights in areas your not actively working, soft weights like a folded canvas dropcloth or similar would probably work best
• You are probably dealing with a natural resident frequency of the boat hull that is sincronous with the vibrating frequency of the sander (So the boat is
Message 6 of 19 , Jul 9, 2010
 You are probably dealing with a natural resident frequency of the boat hull that is sincronous with the vibrating frequency of the sander (So the boat is acting like a bell). Just try to put a couple of weight fore and aft or one in the middle and that may take care of the problem. Otherwise may be a temporary diagonal brace between the sheers may alter the resident frequency of the hull away fron the frequency of the sander. Giuliano  --- On Sat, 7/10/10, Patrick Crockett wrote:From: Patrick Crockett Subject: [bolger] Help with noiseTo: bolger@yahoogroups.comDate: Saturday, July 10, 2010, 12:22 AM I'm doing some repairs on my Windsprint, and when I use the random orbital sander to fair the epoxy/fiberglass the whole boat resonates with a very loud, unpleasant hum. The neighbors finally complained today. I don't really blame them.I can't move it indoors, as I don't have a garage or shed big enough.Does anyone have any ideas for sound suppression?Patrick

• ... I see that I ve described the route of the sample halyard wrongly, having just now picked up the BDQ at home. The line is led to the truck block, then to
Message 7 of 19 , Jul 9, 2010
> I'm following you, but the halyard I have in mind, like those shown on the Mackinac boat, has two attachment points on the gaff at the nominal throat and peak locations. The line is routed from the truck block to a block at the throat, then to another sheave at the truck block, and then to the peak attachment point. Theoretically, once all slack is taken out of the hoist (the leading edge of a gaff sail, but I think it would be called the luff on a lug), the peak should continue to lift as the halyard is hauled on, until all slack is gone from the leech.

I see that I've described the route of the sample halyard wrongly, having just now picked up the BDQ at home. The line is led to the truck block, then to a block at the throat above the gaff jaws, and then along the gaff to a block at the nominal peak halyard location, back to a second sheave on the truck block, and made fast to a becket on the block at the peak. I'd love to know if anyone has ever hoisted such a rig and how well it works.

A potential drawback might be lack of precise control of the peak when lowering sail, as when reefing. Perhaps this is what Mason is getting at.

Jon
• Bruce, ... I m pretty sure that the tiny fraction of the world s population that cares about such things will not think less of you. I count myself in that
Message 8 of 19 , Jul 9, 2010
Bruce,

> You are revealing my ignorance of sailing rig part names.

I'm pretty sure that the tiny fraction of the world's population that cares about such things will not think less of you. I count myself in that small group, but also know that caring doesn't mean getting it correct all of the time myself. Personally, I'm fascinated with the traditional nomenclature not only because of its richness, but because it seeks to eliminate ambiguity. Would that all of our terminology in this world aspire to such goals.

Jon
• Patrick, The resonant frequency of a boat hull is not changed by weights. Natural frequency is solely a function of stiffness, k, divided by mass, m, (sqr
Message 9 of 19 , Jul 9, 2010
Patrick,

The resonant frequency of a boat hull is not changed by weights.  Natural frequency is
solely a function of stiffness, k, divided by mass, m,  (sqr root (k/m)).  The magnitude of the response can be dampened by weights, but the frequency doesn't change.  Since stiffness is lower with longer spans the frequency can be raised by clamping the gunwales to the sawhorses.  This will profoundly alter the resonant behavior of the sides.

Control of the bottom and the chine can be achieved by setting building forms (I'm sure you still have them) inside the hull and clamping them in place.  You could make the forms taller than the depth of the hull and clamp them with ratcheting cargo straps.  You could also increase the stiffness by adding two longitudinals much like the inserts in a liquor box.  This may not get much since the the sander operates at about 10000 cpm.  Total elimination of resonance requires raising the natural frequency to about 60% of this value.   I have, however, reduced the ringing from a cheap Craftsman tank mounted air compressor by strapping a 2x4 to it

The underlying principal can be demonstrated using a ruler and a table edge.  Lay the ruler with 3 inches hanging over the edge and pluck it with your finger.  Now lay it with 6 inch overhang and pluck it.  You can also infer that forms will increase the stiffness from the write-up for Payson's Pirogue, where PCB instructs that the forms remain in place until after the gunwales and thwarts are fitted because the structure lacks stiffness otherwise,

V/R
Chris

On 7/9/2010 11:08 PM, Giuliano Girometta wrote:
 You are probably dealing with a natural resident frequency of the boat hull that is sincronous with the vibrating frequency of the sander (So the boat is acting like a bell). Just try to put a couple of weight fore and aft or one in the middle and that may take care of the problem. Otherwise may be a temporary diagonal brace between the sheers may alter the resident frequency of the hull away fron the frequency of the sander. Giuliano  --- On Sat, 7/10/10, Patrick Crockett wrote: From: Patrick Crockett Subject: [bolger] Help with noise To: bolger@yahoogroups.com Date: Saturday, July 10, 2010, 12:22 AM I'm doing some repairs on my Windsprint, and when I use the random orbital sander to fair the epoxy/fiberglass the whole boat resonates with a very loud, unpleasant hum. The neighbors finally complained today. I don't really blame them. I can't move it indoors, as I don't have a garage or shed big enough. Does anyone have any ideas for sound suppression? Patrick

• I wonder if a setup similar to a mainsheet bridle on the gaff would work. I ll call it a gaff traveler. A length of low-stretch line for a gaff bridle bent on
Message 10 of 19 , Jul 10, 2010
I wonder if a setup similar to a mainsheet bridle on the gaff
would work. I'll call it a gaff traveler. A length of low-stretch line for a gaff bridle bent on at throat and near mid-gaff. A block floating on the bridle with halyard bent to block's shackle. Stopper knots (with twing balls so block won't jam) placed in the bridle; forward stopper knot placed so the yard goes up with the peak eased a bit, and the aft one so the block is kept from jamming at the aft position before tension comes on. This would keep luff tight until the throat is peaked and as the halyard tension comes up the gaff-traveler block drifts aft to tension the peak.

This should provide similar tension geometry to the more normal single-line circuitous halyard setup with a lot less line tail in the cockpit. I suppose it might put more compresssion load on the gaff if the gaff traveler bridle ended up needing to be short to make it function. (short meaning more parallel to the boom)

Maybe I'll call it a graveler or gaffler.

Justin

--- In bolger@yahoogroups.com, "Adirondack Goodboat" <goodboat@...> wrote:
>
> Bruce, I don't think it would be meaningful to call the Solent lug on the alternative (not simpler, rather more complicated) Birdwatcher rig a gaff of any sort. Any lug, I think, is notable for no attachment of luff of sail to mast. The Solent halyard brings the "yard" tight to the masthead sheave, or, if the sail is reefed, a parrel holds the yard very close to the mast, and a downhaul, tensing the luff, hauls the head of yard and sail high. Tres different from gaff. I have little experience with gaffs but geometrically it does seem that a short gaff would do fine with a single halyard placed at the right point. Some of LFH's gaffs are that short; I wonder whether he shows two halyards.(Just looked: Meadowlark and Block Island boat, with very short gaffs, show two halyards and are convincing that that's generally best.) I wouldn't want to do without the various aspects of control the two halyards of the usual gaff provide.
>
> Mason
>
>
> ----- Original Message -----
> From: Bruce Hallman
> To: bolger@yahoogroups.com
> Sent: Friday, July 09, 2010 11:30 AM
> Subject: Re: [bolger] Single Gaff Halyards
>
>
>
> On Fri, Jul 9, 2010 at 8:08 AM, adventures_in_astrophotography
> <jon@...> wrote:
> >
> > Does anyone have experience with single gaff halyards, as opposed to separate peak and throat halyards? I've seen these on a few rigs, usually with relatively short gaffs, such as the 18'-8" Mackinac boat in the latest BDQ (also seen in 50 Wooden Boats). I suspect they must not work as well on longer gaffs or we'd see them more often, but I'd be interested to hear from somebody with real experience.
> >
> > Jon
>
> Doesn't the Solent lug rig (famous with the original simple
> Birdwatcher) have a single halyard gaff? So, that makes me guess that
> the variable is both the length of the gaff in combination with the
> angle of the gaff. (IOW, the more vertical the angle, the longer it
> can be sustained with a single halyard.)
>
• I think what you describe already has a name--gunter: http://en.wikipedia.org/wiki/Gunter ... for a gaff bridle bent on
Message 11 of 19 , Jul 10, 2010

I think what you describe already has a name--gunter:
http://en.wikipedia.org/wiki/Gunter

--- In bolger@yahoogroups.com, "jdmeddock" <jmeddock@...> wrote:
>
>
> I wonder if a setup similar to a mainsheet bridle on the gaff
> would work. I'll call it a gaff traveler. A length of low-stretch line for a gaff bridle bent on at throat and near mid-gaff. A block floating on the bridle with halyard bent to block's shackle. Stopper knots (with twing balls so block won't jam) placed in the bridle; forward stopper knot placed so the yard goes up with the peak eased a bit, and the aft one so the block is kept from jamming at the aft position before tension comes on. This would keep luff tight until the throat is peaked and as the halyard tension comes up the gaff-traveler block drifts aft to tension the peak.
>
> This should provide similar tension geometry to the more normal single-line circuitous halyard setup with a lot less line tail in the cockpit. I suppose it might put more compresssion load on the gaff if the gaff traveler bridle ended up needing to be short to make it function. (short meaning more parallel to the boom)
>
> Maybe I'll call it a graveler or gaffler.
>
>
>
> Justin
>
>
>
>
> --- In bolger@yahoogroups.com, "Adirondack Goodboat" goodboat@ wrote:
> >
> > Bruce, I don't think it would be meaningful to call the Solent lug on the alternative (not simpler, rather more complicated) Birdwatcher rig a gaff of any sort. Any lug, I think, is notable for no attachment of luff of sail to mast. The Solent halyard brings the "yard" tight to the masthead sheave, or, if the sail is reefed, a parrel holds the yard very close to the mast, and a downhaul, tensing the luff, hauls the head of yard and sail high. Tres different from gaff. I have little experience with gaffs but geometrically it does seem that a short gaff would do fine with a single halyard placed at the right point. Some of LFH's gaffs are that short; I wonder whether he shows two halyards.(Just looked: Meadowlark and Block Island boat, with very short gaffs, show two halyards and are convincing that that's generally best.) I wouldn't want to do without the various aspects of control the two halyards of the usual gaff provide.
> >
> > Mason
> >
> >
> > ----- Original Message -----
> > From: Bruce Hallman
> > To: bolger@yahoogroups.com
> > Sent: Friday, July 09, 2010 11:30 AM
> > Subject: Re: [bolger] Single Gaff Halyards
> >
> >
> >
> > On Fri, Jul 9, 2010 at 8:08 AM, adventures_in_astrophotography
> > jon@ wrote:
> > >
> > > Does anyone have experience with single gaff halyards, as opposed to separate peak and throat halyards? I've seen these on a few rigs, usually with relatively short gaffs, such as the 18'-8" Mackinac boat in the latest BDQ (also seen in 50 Wooden Boats). I suspect they must not work as well on longer gaffs or we'd see them more often, but I'd be interested to hear from somebody with real experience.
> > >
> > > Jon
> >
> > Doesn't the Solent lug rig (famous with the original simple
> > Birdwatcher) have a single halyard gaff? So, that makes me guess that
> > the variable is both the length of the gaff in combination with the
> > angle of the gaff. (IOW, the more vertical the angle, the longer it
> > can be sustained with a single halyard.)
> >
>

• I can forgive most minor gaffes about gaffs and yards without feeling the irresistible urge to jump in with a paroxysm of pedantry. But one error,
Message 12 of 19 , Jul 10, 2010
I can forgive most minor gaffes about gaffs and yards <kaff, kaff> without
feeling the irresistible urge to jump in with a paroxysm of pedantry. But
one error, supported by a large class of affordable small sailboats, that
really gets my blood stirring is Sunfish sailers calling the spar that
supports the upper edge of their lateen sails the "upper boom"!! "It's a
YARD, morons!" I feel like yelling at them. <harrumph> I'm glad I got that
off my chest. <g>

A gaff _always_ has its heel bearing against the mast, held with jaws or a
gooseneck fitting. Yards _never_ have their heels attached to the mast.
But never say "never" because the yard of a gunter sail has its heel
attached to the mast! <g> It's still a yard because the gunter descended
from lug rigs. At any rate, you're safe if you see a spar with neither end
attached to the mast and call it a "yard."

On Fri, 09 Jul 2010 21:09:14 -0700, Jon wrote:

> I'm pretty sure that the tiny fraction of the world's population that
> cares about such things will not think less of you. I count myself in
> that small group, but also know that caring doesn't mean getting it
> correct all of the time myself. Personally, I'm fascinated with the
> traditional nomenclature not only because of its richness, but because
> it seeks to eliminate ambiguity. Would that all of our terminology in
> this world aspire to such goals.

--
John (jkohnen@...)
A society that gets rid of all its troublemakers goes downhill.
(Robert A. Heinlein)
• Yeah John. That s right up there with calling a leg o mutton sail with a sprit boom a sprit sail .....retch. Reed
Message 13 of 19 , Jul 12, 2010
Yeah John. That's right up there with calling a leg o mutton sail with a sprit boom a 'sprit sail'.....retch.

Reed

--- In bolger@yahoogroups.com, "John Kohnen" <jhkohnen@...> wrote:
>
> I can forgive most minor gaffes about gaffs and yards <kaff, kaff> without
> feeling the irresistible urge to jump in with a paroxysm of pedantry. But
> one error, supported by a large class of affordable small sailboats, that
> really gets my blood stirring is Sunfish sailers calling the spar that
> supports the upper edge of their lateen sails the "upper boom"!! "It's a
> YARD, morons!" I feel like yelling at them. <harrumph> I'm glad I got that
> off my chest. <g>
>
> A gaff _always_ has its heel bearing against the mast, held with jaws or a
> gooseneck fitting. Yards _never_ have their heels attached to the mast.
> But never say "never" because the yard of a gunter sail has its heel
> attached to the mast! <g> It's still a yard because the gunter descended
> from lug rigs. At any rate, you're safe if you see a spar with neither end
> attached to the mast and call it a "yard."
>
> On Fri, 09 Jul 2010 21:09:14 -0700, Jon wrote:
>
> > I'm pretty sure that the tiny fraction of the world's population that
> > cares about such things will not think less of you. I count myself in
> > that small group, but also know that caring doesn't mean getting it
> > correct all of the time myself. Personally, I'm fascinated with the
> > traditional nomenclature not only because of its richness, but because
> > it seeks to eliminate ambiguity. Would that all of our terminology in
> > this world aspire to such goals.
>
> --
> John (jkohnen@...)
> A society that gets rid of all its troublemakers goes downhill.
> (Robert A. Heinlein)
>
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