Re: Chinese Gaffer rig
c-rusier Thanks for the links. I did finally find a picture which made sense of the cambered sails.http://www.junkrigassociation.org/sailplans_currentIt appears that there is sailcloth at each of the lower battens cut to the shape of the desired sail camber (as if looking at an airplane wing end on) and a panel of flat cut cloth is suspended from the cloth at each batten. Like a model airplane with paper over ribs that form the shape of the wing, except for the junk sail the ribs are cloth hung from a very stiff and straight batten. Wind in the sail blows it into shape. It is not a simple nor inexpensive sail to sew, but it appears that a very effective shape can be made without otherwise harming the good traits of the junk rig. Hinged battens and sails that wrap completely around the mast fastened to hinged battens that also wrap around the mast are just too complicated and fail dangerous to be good go to sea choices. I do expect that the part of the sail that creates the shape must be of very strong sail cloth because there will be much bending of the cloth which over time will weaken it where it bends hard at the batten. It will then rip along the entire length of the batten. Traditional junk sails do not fail so catastrophically. Attention to sail fatigue will be necessary, and prophylactic repairs made well ahead of possible failure. Further reading or questioning on the Junk Rig site might result in enlightenment how the sails are actually sewn, and on the issue of sail fatigue as there are some people who have had twenty and perhaps more years experience with this sail plan.
It still stands that the belly of the sail needs to be in the forward third and the aft part of the sail needs to be flat to let the wind flow smoothly off the aft edge (leach) of the sail.
A comment was made about Colvin at the helm. Colvin lived aboard and sailed his junk rigged boats with out engines for decades, and he did sail those flat cut junk sails to windward. In one case sailed his fifty foot Kung Fu-tse directly to windward out of a 75 yard diameter cul-de-sac in Force 6 (25 to 30 mph) rising winds. For safety he use a method called casting with two anchors so he would be safe if he did not make a tack. His book Cruising as a way of Life is well worth the read for anyone contemplating going to sea.
Eric
It still stands that the belly of the sail needs to be in the forward third and the aft part of the sail needs to be flat to let the wind flow smoothly off the aft edge (leach) of the sail.
A comment was made about Colvin at the helm. Colvin lived aboard and sailed his junk rigged boats with out engines for decades, and he did sail those flat cut junk sails to windward. In one case sailed his fifty foot Kung Fu-tse directly to windward out of a 75 yard diameter cul-de-sac in Force 6 (25 to 30 mph) rising winds. For safety he use a method called casting with two anchors so he would be safe if he did not make a tack. His book Cruising as a way of Life is well worth the read for anyone contemplating going to sea.
Eric
--- Inbolger@yahoogroups.com, "c.ruzer" <c.ruzer@...> wrote:
>
>
>
> Eric, I'm a beginner in this. Does western draft start in Ireland nearly as long ago as Hasler and Mcleod ideas when Dr Vincent Reddish used bricks strategically placed on top of a tarp stretched out on his thick front lawn before cutting the outline, clamping the battens, and promptly setting sail to prove it?
>
> Just think why was James Wharam so disappointed in junksails long ago? Then compare what Gary Dierking is finding now on his test bed wa'apa with a cambered junkrig:http://outriggersailingcanoes.blogspot.com/2010/10/more-junk-rig-tests.htmlfast sailing ability on the wind, and only early days...
>
>
> There's much to learn currently from the knowledgeable and helpful folks on the junkrig group - check out the file section there particularly Arne's files. The JRA site is recently updated - check out the public pages resource there.
>
>http://groups.yahoo.com/group/junkrig/?yguid=140880010
>
>http://www.junkrigassociation.org/
>
>
>
> --- Inbolger@yahoogroups.com, "Eric" <eric14850@> wrote:
> >
> > c.ruzer,
> > What is the source of your information about modern junk sail plans having draft built into them. I know Colvin calls for flat junk sails with no draft. And my memory is that Hastler and Mc*****'s book on the modern junk rig also calls for flat sewn sails. Their insight being to not have so much sail forward of the mast as traditional junk rigs and a few other details. Until ten years or so ago these authors were the go to authorities on the modern junk rig.
> >
> > Eric
>
Eric, I'm a beginner in this. Does western draft start in Ireland nearly as long ago as Hasler and Mcleod ideas when Dr Vincent Reddish used bricks strategically placed on top of a tarp stretched out on his thick front lawn before cutting the outline, clamping the battens, and promptly setting sail to prove it?
Just think why was James Wharam so disappointed in junksails long ago? Then compare what Gary Dierking is finding now on his test bed wa'apa with a cambered junkrig:http://outriggersailingcanoes.blogspot.com/2010/10/more-junk-rig-tests.htmlfast sailing ability on the wind, and only early days...
There's much to learn currently from the knowledgeable and helpful folks on the junkrig group - check out the file section there particularly Arne's files. The JRA site is recently updated - check out the public pages resource there.
http://groups.yahoo.com/group/junkrig/?yguid=140880010
http://www.junkrigassociation.org/
Just think why was James Wharam so disappointed in junksails long ago? Then compare what Gary Dierking is finding now on his test bed wa'apa with a cambered junkrig:http://outriggersailingcanoes.blogspot.com/2010/10/more-junk-rig-tests.htmlfast sailing ability on the wind, and only early days...
There's much to learn currently from the knowledgeable and helpful folks on the junkrig group - check out the file section there particularly Arne's files. The JRA site is recently updated - check out the public pages resource there.
http://groups.yahoo.com/group/junkrig/?yguid=140880010
http://www.junkrigassociation.org/
--- Inbolger@yahoogroups.com, "Eric" <eric14850@...> wrote:
>
> c.ruzer,
> What is the source of your information about modern junk sail plans having draft built into them. I know Colvin calls for flat junk sails with no draft. And my memory is that Hastler and Mc*****'s book on the modern junk rig also calls for flat sewn sails. Their insight being to not have so much sail forward of the mast as traditional junk rigs and a few other details. Until ten years or so ago these authors were the go to authorities on the modern junk rig.
>
> Eric
--- Inbolger@yahoogroups.com, "adventures_in_astrophotography" <jon@...> wrote:
> Personally, I consider that to be a "gaff rig withAgreed.
> full battens and vang(s)" more than a Chinese variant of the
> gaff rig.
>Plus cambered panels with strong battens.
> I'd like to see a CG that employes the key features of the Chinese
> rig - some variant of single halyard, perhaps like those on
> Mackinaw boats, along with a single, multipart sheet to the luff
> of the sail. It's an experiment I wish I had time to conduct.
--- Inbolger@yahoogroups.com, "Eric" <eric14850@...> wrote:
>The above sentence corresponds exactly with my experience on a small boat rigged at first with a traditional flat cut junk sail including Gurney flap then later re-rigged with a two dart (http://marina.fortunecity.com/breakwater/274/1998/1015/index.htm#Lugsails%20From%20Polytarp%201)cambered lug sail that uses full length flexible battens. An experienced sailor saw my first junk rig with Gurney flap and commented that sails work best when air can flow straight off a flat leech and that the Gurney flap should be got rid of.
>
> In modest sizes, a well cut and well set balanced lug rig with the yard rigged so that the yard drops parallel with the boom, with lazy jacks and several jiffy reef points, will be much more efficient to windward, almost as easy to reef, and just as docile as a junk sail.
>
Thank you for the link. I now understand what is meant by cambered junk sail.
You can instantly get a sail this shape by cutting the leach (the flat cut aft section of the sail) off the mainsail of a sail that doesn't fit the space available. I did this to test the balance of ROGUE. The result is a sail that is so ill performing it may well decrease the speed of the boat rather than increase it. The reason is the resultant "camber" at the area of the sail that is now the leach causes the wind over the sail to eddy around to the back side of the sail which acts as a very effective airbrake, because this redirected air is now flowing DIRECTLY TO WINDWARD along the windward side of the sail (confirmed, not theoretical).
My suspicion is that the "gurney flap" improves things prevents the backwinding of the windward side of the cambered junk sail so that the wind eddies horribly but less harmfully off the back of the "gurney flap" than it would without the gurney flap. The gurney flap may also create an area of dead air over the leeward side of the sail resulting in an approximation of the flat bottom of an airplane wing. A bunch of colorful tread all over the sail would reveal a good deal about this. smoke would reveal what happens past the aft edge of the sail. (I am accept the author's statement that the "gurney flap" improves the cambered sail, but there is no clear indication it would improve the performance of a Colvin or Hasler designed flat cut junk sail, and one should not assume it would.)
I'm willing to bet that in a two masted rig the foresail would so mess with the wind that it would decrease the effectiveness of the sail aft of it.
Reasons to use a junk sail: lack of access to adequate sail cloth, lack of ability to sew or purchase a good sail shape, very large sail area and small crew of modest strength who have a desire to use a sail that is docile and fails safe. and what better reason than that wonderful past-time messing about in boats, experimenting with the junk rig.
In modest sizes, a well cut and well set balanced lug rig with the yard rigged so that the yard drops parallel with the boom, with lazy jacks and several jiffy reef points, will be much more efficient to windward, almost as easy to reef, and just as docile as a junk sail.
Eric
You can instantly get a sail this shape by cutting the leach (the flat cut aft section of the sail) off the mainsail of a sail that doesn't fit the space available. I did this to test the balance of ROGUE. The result is a sail that is so ill performing it may well decrease the speed of the boat rather than increase it. The reason is the resultant "camber" at the area of the sail that is now the leach causes the wind over the sail to eddy around to the back side of the sail which acts as a very effective airbrake, because this redirected air is now flowing DIRECTLY TO WINDWARD along the windward side of the sail (confirmed, not theoretical).
My suspicion is that the "gurney flap" improves things prevents the backwinding of the windward side of the cambered junk sail so that the wind eddies horribly but less harmfully off the back of the "gurney flap" than it would without the gurney flap. The gurney flap may also create an area of dead air over the leeward side of the sail resulting in an approximation of the flat bottom of an airplane wing. A bunch of colorful tread all over the sail would reveal a good deal about this. smoke would reveal what happens past the aft edge of the sail. (I am accept the author's statement that the "gurney flap" improves the cambered sail, but there is no clear indication it would improve the performance of a Colvin or Hasler designed flat cut junk sail, and one should not assume it would.)
I'm willing to bet that in a two masted rig the foresail would so mess with the wind that it would decrease the effectiveness of the sail aft of it.
Reasons to use a junk sail: lack of access to adequate sail cloth, lack of ability to sew or purchase a good sail shape, very large sail area and small crew of modest strength who have a desire to use a sail that is docile and fails safe. and what better reason than that wonderful past-time messing about in boats, experimenting with the junk rig.
In modest sizes, a well cut and well set balanced lug rig with the yard rigged so that the yard drops parallel with the boom, with lazy jacks and several jiffy reef points, will be much more efficient to windward, almost as easy to reef, and just as docile as a junk sail.
Eric
--- Inbolger@yahoogroups.com, "adventures_in_astrophotography" <jon@...> wrote:
>
> There was a good article on Duckworks describing how one man designed and built his cambered junk rig:
>http://www.duckworksmagazine.com/06/howto/junkrig/index.htm
>
> I suppose that adding camber, if done just so, moves the center of aerodynamic force closer to the quarter-chord location like that of an aircraft wing. If this were true, it would reduce weather helm. One way to bias the camber forward would be to cut the darts in the luff smaller than those in the leech, referring to the sail shaping technique in the link above.
>
> I have also heard of making the camber progressively less in upper panels so that when reefed down, the sail is flatter. It seems like this could be done in the Chinese Gaff as well. It's possible that any advantage in strong wind produced by this effect would be less than the performance penalty incurred in light wind by the upper part of the sail, and I don't think I'd use this approach.
>
> From the examples I've seen, it doesn't appear that anybody is using Hasler-style sheets on the CG. They all seem to have multiple sheets, including some with a conventional sheet on the boom. Personally, I consider that to be a "gaff rig with full battens and vang(s)" more than a Chinese variant of the gaff rig. In particular, a sheet on the boom negates one of the advantages of the Chinese rig, that lowering the halyard automatically slacks off the sheet.
>
> I'd like to see a CG that employes the key features of the Chinese rig - some variant of single halyard, perhaps like those on Mackinaw boats, along with a single, multipart sheet to the luff of the sail. It's an experiment I wish I had time to conduct.
>
> Jon
>
There was a good article on Duckworks describing how one man designed and built his cambered junk rig:
http://www.duckworksmagazine.com/06/howto/junkrig/index.htm
I suppose that adding camber, if done just so, moves the center of aerodynamic force closer to the quarter-chord location like that of an aircraft wing. If this were true, it would reduce weather helm. One way to bias the camber forward would be to cut the darts in the luff smaller than those in the leech, referring to the sail shaping technique in the link above.
I have also heard of making the camber progressively less in upper panels so that when reefed down, the sail is flatter. It seems like this could be done in the Chinese Gaff as well. It's possible that any advantage in strong wind produced by this effect would be less than the performance penalty incurred in light wind by the upper part of the sail, and I don't think I'd use this approach.
From the examples I've seen, it doesn't appear that anybody is using Hasler-style sheets on the CG. They all seem to have multiple sheets, including some with a conventional sheet on the boom. Personally, I consider that to be a "gaff rig with full battens and vang(s)" more than a Chinese variant of the gaff rig. In particular, a sheet on the boom negates one of the advantages of the Chinese rig, that lowering the halyard automatically slacks off the sheet.
I'd like to see a CG that employes the key features of the Chinese rig - some variant of single halyard, perhaps like those on Mackinaw boats, along with a single, multipart sheet to the luff of the sail. It's an experiment I wish I had time to conduct.
Jon
http://www.duckworksmagazine.com/06/howto/junkrig/index.htm
I suppose that adding camber, if done just so, moves the center of aerodynamic force closer to the quarter-chord location like that of an aircraft wing. If this were true, it would reduce weather helm. One way to bias the camber forward would be to cut the darts in the luff smaller than those in the leech, referring to the sail shaping technique in the link above.
I have also heard of making the camber progressively less in upper panels so that when reefed down, the sail is flatter. It seems like this could be done in the Chinese Gaff as well. It's possible that any advantage in strong wind produced by this effect would be less than the performance penalty incurred in light wind by the upper part of the sail, and I don't think I'd use this approach.
From the examples I've seen, it doesn't appear that anybody is using Hasler-style sheets on the CG. They all seem to have multiple sheets, including some with a conventional sheet on the boom. Personally, I consider that to be a "gaff rig with full battens and vang(s)" more than a Chinese variant of the gaff rig. In particular, a sheet on the boom negates one of the advantages of the Chinese rig, that lowering the halyard automatically slacks off the sheet.
I'd like to see a CG that employes the key features of the Chinese rig - some variant of single halyard, perhaps like those on Mackinaw boats, along with a single, multipart sheet to the luff of the sail. It's an experiment I wish I had time to conduct.
Jon
There's a junkrig group on Yahoo that is quite active. Some of those
folks have been using junk rig for years, and have cruised thousands of
miles with them in all sorts of conditions. Annie Hill, author of
"Voyaging on a Small Income," often contributes a few posts when she's
in port somewhere. Also, there's a Junk Rig Association in the UK.
Some of these folks have done a lot of exprimenting with cambered sails,
hinged battens, and other unusual techniques to improve the performance.
The consensus seems to be that a flat-cut junk sail will perform like
most old-fashioned types, i.e. not so great upwind, but fine for
everything else. The newer, cambered sails have noticeably better
upwind performance. That's what I plan to use for the next set of sails
I make. For now, the flat ones get me around OK; I'm in no hurry. (See
http://themagicm.com/kent/reaching-may2010.jpg)
Also, for the Trilobat fans out there, check out the Articles page at
http://triloboats.comThere are some new reports of sea trials with
the 26ft. junk-schooner-barge.
folks have been using junk rig for years, and have cruised thousands of
miles with them in all sorts of conditions. Annie Hill, author of
"Voyaging on a Small Income," often contributes a few posts when she's
in port somewhere. Also, there's a Junk Rig Association in the UK.
Some of these folks have done a lot of exprimenting with cambered sails,
hinged battens, and other unusual techniques to improve the performance.
The consensus seems to be that a flat-cut junk sail will perform like
most old-fashioned types, i.e. not so great upwind, but fine for
everything else. The newer, cambered sails have noticeably better
upwind performance. That's what I plan to use for the next set of sails
I make. For now, the flat ones get me around OK; I'm in no hurry. (See
http://themagicm.com/kent/reaching-may2010.jpg)
){kind=link}
Also, for the Trilobat fans out there, check out the Articles page at
http://triloboats.comThere are some new reports of sea trials with
the 26ft. junk-schooner-barge.
> c.ruzer,
> What is the source of your information about modern junk sail plans having draft built into them. I know Colvin calls for flat junk sails with no draft. And my memory is that Hastler and Mc*****'s book on the modern junk rig also calls for flat sewn sails. Their insight being to not have so much sail forward of the mast as traditional junk rigs and a few other details. Until ten years or so ago these authors were the go to authorities on the modern junk rig.
>
> Eric
c.ruzer,
What is the source of your information about modern junk sail plans having draft built into them. I know Colvin calls for flat junk sails with no draft. And my memory is that Hastler and Mc*****'s book on the modern junk rig also calls for flat sewn sails. Their insight being to not have so much sail forward of the mast as traditional junk rigs and a few other details. Until ten years or so ago these authors were the go to authorities on the modern junk rig.
Eric
What is the source of your information about modern junk sail plans having draft built into them. I know Colvin calls for flat junk sails with no draft. And my memory is that Hastler and Mc*****'s book on the modern junk rig also calls for flat sewn sails. Their insight being to not have so much sail forward of the mast as traditional junk rigs and a few other details. Until ten years or so ago these authors were the go to authorities on the modern junk rig.
Eric
--- Inbolger@yahoogroups.com, "c.ruzer" <c.ruzer@...> wrote:
>
>
>
> The rig is supposed to eliminate some of the bad qualities of the gaff and bad qualities of the junk, and to combine their better qualities.
>
> A significant thing is that the alleged plate aerodynamics of the junk are improved somehow. I don't get it. Is that supposedly because the sail luff has a mast before it?
>
> The Chinese Gaff sail is made flat in the most conventional western interpretation, not Chinese, junk manner. The CG has flexible battens that are meant to induce camber. Junkies, and Jim Melcher have found that if the battens are flexible enough to allow increased camber sufficient to markedly improve lift then problems always follow - before and after the inevitable batten breakages.
>
> Chinese junks, like western gaffs, used to be made of fabric that stretched, increasingly so over time. The stretching of the fabric meant there was camber in the sail panels.
>
> The junk has been rethunk for the modern not-very-stretchy sail making materials. The junk may be constructed from modern very durable and economical fabric alternatives, such as Sunbrella etc., instead of the usual dacron, mylar, etc. The rethunk junk panels are sewn with camber included. There's the simple gathered method, foot or lens shelf approach, or the barrel cut method, for example. Analysis has shown the aerodynamics of such junk sails to be at least the equivalent of a conventional western well cut jib headed sail. These junk sails retain all the advantages inherent in the junk including having strong, stiff battens.
>
> I'd be very interested in hearing how the Bolger Chinese Gaff sail could be a better cruising option than a modern rethunk junk.
>
>
>
> --- Inbolger@yahoogroups.com, "Bob" <bob-norris@> wrote:
> >
> > Hi all -- Does anyone know how PCB's Chinese Gaffer rig actually worked in practice? The plans I saw had 3 separate mainsheets, and 3 separate reefing downhauls that went through a cheek block on the tabernacle, up to the top of the mast, and down to a cleat on deck. Seemed like an awful lot of string to me. I know Jim Melcher tried it on his Alert, but eventually went with a traditional junk rig. Only one mainsheet, and battens pretty much drop into place by themselves.
> > Thanks for your help.
> >
>
> but I have built a Chinese Gaff per design, and I have used thisWith respect, Melcher's rig like Bolger's Chinese Gaffer (CG) rig used flexible battens to induce camber into the flat cut cloth. Melcher had batten breakages just as reported for flexible battens used on western (a la Hasler, Macleod, Van Loan, et al) junk rigs. IIRC broken battens tore Melcher's sail pretty badly at an inopportune time. Stronger, stiffer battens incorporating hinges induce camber, have less breakage issues, but present another set of problems in design, manufacture, and cost. The recent approach in having junk panels each cut and/or sewn with camber has all the strengths of the usual junk sail, just a few of which are common to the CG, plus great aerodynamics.
> Chinese Gaff and I can report that it works as advertised.
The angle of the sheetlet leads can only be a marginal issue. Junks aren't prone to "death rolls", but gaffs are - junks are regularly sailed downwind with the sail sheeted before the mast (but haul on the sheet only if the battens are stiff and strong enough!). Gaffs sailed by the lee are quite prone to induced rythmic roll. Junks have sufficient sheetlet lead to control the upper sail, more so in situations where this possibly could occur as the lead angle is less anyway due to the ease of reefing and consequent lowered sail. The upper panels when fully raised are also likely to have less camber induced into the battens by sheeting forces due to the lower mechanical advantage of a steeper sheetlet lead which in turn means sheeting forces there will be less than otherwise. The junk yard is always required to be stiff and strong, inflexible, though I guess it could be hinged.
In rethunk junk sails with camber sewn into each panel there is yet more control. The upper panels are sewn with decreasing camber as height increases. This suitably matches panels to the normal higher wind speeds occuring progressively aloft, and to those occuring below when lowered in the reefed situation as the more cambered bottom panels are progessively furled.
-------
A Ha! Xmas Tree Proa Sail...
For what it is worth, I had a brief correspondence with Phil Bolger
regarding Jim Melcher's Chinese Gaff rig on Alert. Phil Bolger was also
critical of that rig, writing:
"As to Melcher's problems, he rig was a makeshift in the first
place. (to use as much of the existing gear and structure as
possible and he also did not make the most of it in several ways.
We did not at all like his sheeting arrangements when he was here,
and thinks at least part of his trouble would have been avoidable
with more thought."
In short, I don't think Jim Melcher understood the design concept
behind the Bolger Chinese Gaff rig, and the ChG version Melcher
created was doomed to not work properly because he sheeted it wrong.
Certainly, not all ChG rigs are the same.
As to the "awful lot of strings", true. What those extra strings get
you is the ability to have all your sail cloth up at once, and then to
have it all reefed at whim from the safety of the cabin. Compare that
to most other rigs where when things really get blowing you need to go
up on deck and swap out the sails while exposed to danger. The extra
sheet-lets which lead from high up on the aft sheet staff (mizzen
mast) give you a degree of control over the shape of the gaff sail not
possible with the standard Chinese Lug rig or standard gaff rigs
(which sheet from the deck elevation). I was told that this controls
the "death roll" oscillation problem when running downwind, which I
think is true.
I admit that I am more of a marina sailor than a true salty sailor,
but I have built a Chinese Gaff per design, and I have used this
Chinese Gaff and I can report that it works as advertised.
regarding Jim Melcher's Chinese Gaff rig on Alert. Phil Bolger was also
critical of that rig, writing:
"As to Melcher's problems, he rig was a makeshift in the first
place. (to use as much of the existing gear and structure as
possible and he also did not make the most of it in several ways.
We did not at all like his sheeting arrangements when he was here,
and thinks at least part of his trouble would have been avoidable
with more thought."
In short, I don't think Jim Melcher understood the design concept
behind the Bolger Chinese Gaff rig, and the ChG version Melcher
created was doomed to not work properly because he sheeted it wrong.
Certainly, not all ChG rigs are the same.
As to the "awful lot of strings", true. What those extra strings get
you is the ability to have all your sail cloth up at once, and then to
have it all reefed at whim from the safety of the cabin. Compare that
to most other rigs where when things really get blowing you need to go
up on deck and swap out the sails while exposed to danger. The extra
sheet-lets which lead from high up on the aft sheet staff (mizzen
mast) give you a degree of control over the shape of the gaff sail not
possible with the standard Chinese Lug rig or standard gaff rigs
(which sheet from the deck elevation). I was told that this controls
the "death roll" oscillation problem when running downwind, which I
think is true.
I admit that I am more of a marina sailor than a true salty sailor,
but I have built a Chinese Gaff per design, and I have used this
Chinese Gaff and I can report that it works as advertised.
On Mon, Mar 21, 2011 at 5:53 PM, Bob <bob-norris@...> wrote:
>
>
>
> Hi all -- Does anyone know how PCB's Chinese Gaffer rig actually worked in practice? The plans I saw had 3 separate mainsheets, and 3 separate reefing downhauls that went through a cheek block on the tabernacle, up to the top of the mast, and down to a cleat on deck. Seemed like an awful lot of string to me. I know Jim Melcher tried it on his Alert, but eventually went with a traditional junk rig. Only one mainsheet, and battens pretty much drop into place by themselves.
> Thanks for your help.
--- Inbolger@yahoogroups.com, "Bob" <bob-norris@...> wrote:
There are at least three Micros rigged that way; Bruce Hallman [he of
the wonderful FreeShip models] has a Navigator, Don [Baldwin?] rebuilt
his Micro as a Navigator, and our regular cuddy Micro is rigged with a
CG mainsail.
fine tuning the leech. You sail the boat handling the mainsheet, and
only address the others at need [or if you can be troubled]. To answer
your question directly, for us at any rate, it has worked fairly well.
The sail drops neatly into the lazy-lifts. It's perhaps a bit elaborate
for a sixteen foot boat.
involved.
>worked in practice?
> Hi all -- Does anyone know how PCB's Chinese Gaffer rig actually
There are at least three Micros rigged that way; Bruce Hallman [he of
the wonderful FreeShip models] has a Navigator, Don [Baldwin?] rebuilt
his Micro as a Navigator, and our regular cuddy Micro is rigged with a
CG mainsail.
>The plans I saw had 3 separate mainsheetsMore like a mainsheet and a gaff vang, and an intermediate sheet for
fine tuning the leech. You sail the boat handling the mainsheet, and
only address the others at need [or if you can be troubled]. To answer
your question directly, for us at any rate, it has worked fairly well.
The sail drops neatly into the lazy-lifts. It's perhaps a bit elaborate
for a sixteen foot boat.
> Seemed like an awful lot of string to me.It's a gaff rig with slab reefing. Yes, there's a fair amount of cordage
involved.
The rig is supposed to eliminate some of the bad qualities of the gaff and bad qualities of the junk, and to combine their better qualities.
A significant thing is that the alleged plate aerodynamics of the junk are improved somehow. I don't get it. Is that supposedly because the sail luff has a mast before it?
The Chinese Gaff sail is made flat in the most conventional western interpretation, not Chinese, junk manner. The CG has flexible battens that are meant to induce camber. Junkies, and Jim Melcher have found that if the battens are flexible enough to allow increased camber sufficient to markedly improve lift then problems always follow - before and after the inevitable batten breakages.
Chinese junks, like western gaffs, used to be made of fabric that stretched, increasingly so over time. The stretching of the fabric meant there was camber in the sail panels.
The junk has been rethunk for the modern not-very-stretchy sail making materials. The junk may be constructed from modern very durable and economical fabric alternatives, such as Sunbrella etc., instead of the usual dacron, mylar, etc. The rethunk junk panels are sewn with camber included. There's the simple gathered method, foot or lens shelf approach, or the barrel cut method, for example. Analysis has shown the aerodynamics of such junk sails to be at least the equivalent of a conventional western well cut jib headed sail. These junk sails retain all the advantages inherent in the junk including having strong, stiff battens.
I'd be very interested in hearing how the Bolger Chinese Gaff sail could be a better cruising option than a modern rethunk junk.
A significant thing is that the alleged plate aerodynamics of the junk are improved somehow. I don't get it. Is that supposedly because the sail luff has a mast before it?
The Chinese Gaff sail is made flat in the most conventional western interpretation, not Chinese, junk manner. The CG has flexible battens that are meant to induce camber. Junkies, and Jim Melcher have found that if the battens are flexible enough to allow increased camber sufficient to markedly improve lift then problems always follow - before and after the inevitable batten breakages.
Chinese junks, like western gaffs, used to be made of fabric that stretched, increasingly so over time. The stretching of the fabric meant there was camber in the sail panels.
The junk has been rethunk for the modern not-very-stretchy sail making materials. The junk may be constructed from modern very durable and economical fabric alternatives, such as Sunbrella etc., instead of the usual dacron, mylar, etc. The rethunk junk panels are sewn with camber included. There's the simple gathered method, foot or lens shelf approach, or the barrel cut method, for example. Analysis has shown the aerodynamics of such junk sails to be at least the equivalent of a conventional western well cut jib headed sail. These junk sails retain all the advantages inherent in the junk including having strong, stiff battens.
I'd be very interested in hearing how the Bolger Chinese Gaff sail could be a better cruising option than a modern rethunk junk.
--- Inbolger@yahoogroups.com, "Bob" <bob-norris@...> wrote:
>
> Hi all -- Does anyone know how PCB's Chinese Gaffer rig actually worked in practice? The plans I saw had 3 separate mainsheets, and 3 separate reefing downhauls that went through a cheek block on the tabernacle, up to the top of the mast, and down to a cleat on deck. Seemed like an awful lot of string to me. I know Jim Melcher tried it on his Alert, but eventually went with a traditional junk rig. Only one mainsheet, and battens pretty much drop into place by themselves.
> Thanks for your help.
>
Hi all -- Does anyone know how PCB's Chinese Gaffer rig actually worked in practice? The plans I saw had 3 separate mainsheets, and 3 separate reefing downhauls that went through a cheek block on the tabernacle, up to the top of the mast, and down to a cleat on deck. Seemed like an awful lot of string to me. I know Jim Melcher tried it on his Alert, but eventually went with a traditional junk rig. Only one mainsheet, and battens pretty much drop into place by themselves.
Thanks for your help.
Thanks for your help.