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View Full Version : windward ability of different rigs (gaff compared to bermudan)



Patrik111
08-21-2000, 07:13 PM
Hello,
I'm going to build a 14ft sailing centerboard dinghy in wood. I would lke to know if anyone has some "scientific" comparative figures on windward ability of gaff, spri, bermudan, and wishbone rigs.
Can one sail as close to the wind?
Is the lift/drag ratio much worse?


I would like to have it gaff rigged but am a bit concerned when everybody seems to believe it's much inferior to the bermudan rig ( espicially on a beat).

ACB
08-21-2000, 11:00 PM
My 37ft gaff cutter tacks through 110 degrees. This is a very poor show compared to a modern Bermudian rig which should tack through 80 degrees. But, with boats as with wives, "Be to her virtues ever kind; be to her faults a little blind".

Don't even think about gaff rig on a 14 footer. If you need short spars, to stow in the boat, use a gunter lug rig.

Bruce Hooke
08-21-2000, 11:16 PM
Scientific comparisons certainly have been done between many different rigs. There was a good article in WoodenBoat 92 (Jan/Feb 1990) comparing a variety of different rigs (note: for gaff rigs you need to look carefully because it is treated as a modified Bermudan rig). The gist of these tests seems to be that the supposed advantage of the Bermudan rig is not nearly as big as it is often made out to be. For more on the science side you might want to take a look at C.A. Marchaj's "The Aero-Hydrodynamics of Sailing" although it has been so long since I read it that I cannot remember how much it looks at different rigs. (I just noticed that he has a new book out: "Sail Performance : Designs and Techniques to Maximize Sail Power" - might be worth taking a look at...)

That said, on a small boat there are other issues that I think should carry more weight than windward ability. Here are some of them:

- How easy is the rig to set up and take down?
- Can the spars be stowed inside the boat?
- If you don't like hanging out over the side of the boat in a breeze to keep the boat from tipping over an important question is how low is the sail area. A tall rig like a typical Bermudan setup can exert much more healing force than a low spread out rig like a sprit rig. Also, a rig with a lot of weight up high can have the same effect (this is one problem with the gaff rig).

Keep in mind too that for almost any rig there are many details that can make a huge difference in efficiency. Paying attention to these details will probably pay a much bigger dividend than simply selecting what is supposed to be a more efficient rig.

- Bruce

John B
08-22-2000, 12:30 AM
i really enjoy the gaff rig after converting back to my yacht's original configuration last year but i agree with ACB and would look at gunter in a vessel your size.
a book that i found very interesting was called " yacht racing" (aren't they all?) by manfred curry from about the mid 1920's. if i recall it's intro correctly it was touted as the first scientific approach to the issues of aerodynamics/ hydrodynamics in yachting. whether modern designers ( or other contempories) would agree with that i don't know but regardless it was certainly interesting reading if you could find a copy.full of graphs and experiments in sail and foil shape and rig .i think he was american of german extraction and spent a lot of time in germany between the wars wind tunnel testing the gaff rig v. the new bermudans.i think the book was first printed in german and then translated to english.
my personal experience of the change from bermudan to gaff in our keeler is that we have not lost any windward performance but have substantially improved eased sheets .i just don't think the same rules apply in a centreboarder. it will be interesting to see the other opinions on that....

Ian McColgin
08-22-2000, 08:08 AM
Hull and rig must match.

With the right hull, the triangular shape will triumph to weather but you need some kites off the wind.

However, a hull well suited to the gaff rig can be a right pig under marconi - like a Cape Cod Cat boat. Even some slick hulls are better under the original gaff - see Roger Taylor's remarks about rigs in his old Buzzards Bay 25.

A radical high roach full batten sail is probably the hottest sail around, and that's really just a gaff with topsail and incredibly great air foil control.

Balance is all.

Tom Lathrop
08-22-2000, 08:56 AM
Patrik,

You don't say whether your boat is a sloop or cat rigged. If it is cat rigged, my favorite would be a sprit boomed marconi with an unstayed mast. This rig is the simplest to rig and unrig, the sail can stay on the mast, can be rolled up on the mast on the water, it is self vanging, with a mast of proper stiffness it adjusts to wind gusts and gives up very little to the racing rig in performance. If your boat was a bit larger, I'd suggest the cat-ketch with the above sails. It has lots of advantages for day sailing.

There is ample proof that a marconi is superior to a gaff rig in windward ability. All designers of high performance racing boats choose the marconi rig. As others have said, the rig must match the boat no matter which you choose.

The books mentioned are a great source of information. I don't know if Curry was the first to look at sails, hulls and foils scientifically, but he was certainly the first to develop the racing tactics that are still used today.

Bruce Hooke
08-22-2000, 10:10 AM
Actually, there seems to be a respectable amount of research suggesting that the marconi rig is not that superior to some other rigs IF the comparison is made based on actual sail area rather than the arbitrary racing rule measurement that takes the foretriangle area as the area of the headsail. A (or even the) major reason for the predominance of the marconi rig on "modern" sailboats appears to be that the standard racing rules favor the marconi rig and cruising boats tend to follow what the racers do. - Bruce

Tom Lathrop
08-23-2000, 09:45 PM
Bruce, I've seen a lot of writing that make the claim of other rigs than the marconi being superior or equal but other than off the wind courses, I've never seen anything that corresponds to proof. The claim that the "rating rule" favors the marconi rig is partly true but not sufficient to cause the great favor of this rig that exists. For instance, in races where there is no rule, like the round the globe races, all the boats sport some form of the sloop/marconi rig.

In the last singlehander, one boat was a cat ketch with no jibs. It quit on the first leg because it simply could not keep up with the other boats. Sail area in this case is limited only by the carrying ability of the boat and the guts of the sailors.

Nature certainly favors the marconi rig for birds and even sea creatures. It's hard to beat mother nature in finding the most efficient form for using natural forces.

John B
08-23-2000, 11:36 PM
i think i might be enjoying this forum as much as sailing my boat..

i don't think there is any doubt that the bermudan rig is superior to the gaff in ultimate terms but there are other issues.

like fear is supposed to be character forming ,isn't it ?

i spent a lot of time trying to think out ways to get the best performance of my new gaff mainsail but the big surprise to me was just how hard it was to get the jibs right with the amount of forestay sag one gets without a standing backstay. you just have to accept it and get the sails cut accordingly. of course the modern racers (and often cruisers)have bar tight forestay tension for their beautiful exotic sails.
The point i'm making is that there is a tendency to look to the mainsail in the rig debate when perhaps there is more of an issue than we'd expect with the babies up front.
we don't have catboats here in NZ as a rule but i'd certainly be interested to know how the catboat gaffs go next to the bermudan catboats on the wind.
my feeling is that if you want a gaff rig to go as well as a bermudan on average you have to cheat a little and have more sail area to compensate for efficiency,.

glorious fun though..

Bruce Hooke
08-24-2000, 10:21 AM
For "proofs" check out WoodenBoat 92 (Jan/Feb 1990). An article in that issue has wind tunnel test data, polar diagrams, etc., and the comparisons held up even for beating to windward. That said, my feeling is that this is still an open issue, in part because of things like the choices made for "open" races that Tom refers to. One other influence on those choices may be that the money spent on perfecting the marconi rig over the last 50 years probably exceeds the money spent on perfecting every other possible rig by a couple orders of magnitude or more.

As regards birds, the wing of a bird looks rather like a catboat to me, which some would argue is not very efficient, so, with all due respect, I wouldn't give that argument too much weight. Also, it is worth remembering that in all of evolution "nature" never came up with the wheel. I think it might be better to say that nature is good at doing amazing things with what you might call very limited technology, but we have to be pretty careful when we try to model things after nature...

- Bruce

Tom Lathrop
08-24-2000, 10:51 PM
Bruce, I will have to study the article more carefully to have a strong opinion of the data. On the surface, I'm puzzled that the author's most efficient (crab claw) and the least efficient (lateen) appear to be almost identical in form. Makes me wonder. The lack of a backstay to tension the jib liff will limit windward potential of all rigs other than the marconi and this is never considered in tests on metal or rigid-sail wind tunnel testing.

Everyone always has different theories, but I heard that the crab claw rig was evolved for small boats sailing in ocean waves so that the sail would not be blanketed by the waves. Anyone who has sailed a small boat in the ocean knows the problem.

For research, aeronautical engineers have outdone all sailing development by orders of magnitude and they generally favor the eliptical single foil as the most efficient (the Spitfire is a good example). High tech multihulls usually have cat rig wingsails when sail area is limited. The sloop marconi excells when all points of sail are considered as the cat suffers off the wind. Don't forget the effect of spinakers on the choice of rigs either.

You are right that nature did not come up with the wheel, at least in the animal kingdom. What would be the application that created the need for a wheel in nature? I have no Idea. Borrowing nature's designs should be done with discretion. Remember the cod's head and mackerel tail hull shape? Nevertheless, thousands of bird species have all evolved pretty much the same wing form, and there are no gaffs or crabclaws among them.

It's an interesting discussion but most of us will wind up liking our own favorite sail rig in spite of any evidence to the contrary.

Keith Wilson
08-25-2000, 08:58 AM
The fact that almost all development work done in the past 80 years has been on the bermudan rig makes theoretical comparisons of different sail rigs somewhat irrelevant. If you want to go well to windward in a medium-sized boat (say between 15 and 50 feet) without doing a lot of research yourself, use a standard bermudan rig. You'll have the benefit of many many other people's work.

For really small boats, other rigs have significant advantages - simplicity, cost, short spars - I like the sharpie rig myself, self-vanging and low sheet forces, but for windward performance, and once you get into slightly larger boats, there has been so much more work done on the bermudan rig that it's way ahead of everything else, despite distortions caused by rating rules. Development on the Gaff rig stopped about 1920, well before synthetic sailcloth and rope.

I'd highly recommend Phil Bolger's boat on Small Boat Rigs - try this link:
http://dogbert.abebooks.com/abe/BookDetails?bi=66462921

I'd be leery of drawing analogies from either birds or aircraft - both go MUCH faster than the normal sailboat. What works at 40 MPH on a goose or at 400 MPH on a Spitfire may not work well at all at 5 MPH on a boat.

Tom Lathrop
08-25-2000, 02:41 PM
Of course, drawing analogies from the animal kingdom can lead to some wrong conclusions. However the wing forms of the 400mph Spitfire, the 40mph goose and the 5mph vulture, eagle or hawk are nearly identical. I am wont to dismiss this as a mere curiosity.

jason
08-25-2000, 02:52 PM
lets not forget that certain sailing records even to this day wrt speen are still held by histirc clippers, schooners etcc..no need for fancy scientidic comparisons..imo you go for the one you think you will enjoy...after all, sailing is part fantasy for all......no need to be the fastest on the water, nor the most modern..... some prefer the most handsome

scottek
08-25-2000, 03:58 PM
Not including fully battened mains as gaff rigged (one halyard vs peak and yoke halyards). A benefit of the bermuda/marconi rig is the use of mast bend to controll foil (sail) shape (per Ian's comment). The greater the foil controll will allow you to perform in a wider range of wind conditions. Other windward performance issues: The size of the mast (diameter) has a huge impact on the foils windward efficiency. Also higher aspect foils (long and narrow) achieve greater windward efficiency (i.e. glider wing = highly efficient) One aspect to consider in windward ability is your hull speed, you may be better at a greater angle to the wind if your overall speed is better (i.e. A multihull or any planning hull may have to sail at a greater angle to the wind, thus having to travel 2.5 times the distance of a close hauled boat. But, if the planning boat is going 3 times as fast, it will reach the windward mark first. If you are really concerned about windward performance, I also recommend "HIGH PERFORMANCE SAILING" by Frank Bethwaite. For those of us who could care less about ease of handling and yern for white knuckle excitement...

When you take a close study of nature, you relise it did not need to come up with the wheel. Name one man made device that is capable of manuvering a load greater than itself with the ease and agility of that of an ant. Scientists and engineers (from Caregie Mellon?) are trying to create a man made version of a cockroach; exoskeleton, agile, fast, and jumping capabilities (wheels have a hard time jumping!) for use as a exploration robot. Other scientist are trying to make water robots with swimming characteristics to that of tuna. As far as nature goes, man still has a long way to catch up...

-YF Scott

Smacksman
08-25-2000, 05:32 PM
I think I said this somewhere else recently but here goes with my six penneth... We had two 28' class racing boats sailing matchs, one gaff, one bermudan. Same hulls and same sail area to the class rules which had developed from gaff to bermudan. Gaff won each time, just! Performance off wind scored more than the bit lost to windward and I have to say, the gaffer was the better skipper.

John B
08-25-2000, 09:58 PM
smacksman
that little gem of information is the sort of thing i wondered about for years, but can you clarify. were they actually the same sail areas or were they rated sail areas and what were the rig configurations? topsail v genoa or was it a working sail match up?
john

Foster Price
08-26-2000, 04:25 AM
Hello Guys

Seems to me that gaff is generally shorter in luff lenght than its bermudian equivalant of the same area.

Luff lenght is very important in getting to windward so perhaps there is room to work on higher aspect gaffers.

Would this take us back to the lug rigs, especially really modern ones like Nigel Irens gave "Roxanne" and "Rhomily". They have "blitzed" a couple of fleets so I hear (don't have any idea of the quality of same

Regards
Foster Price
Southland, New Zealand

Smacksman
08-26-2000, 05:31 AM
JohnB - The match was in East Coast One Designs and the news I got which impressed me was that the sail area was the same. The gaffer was Chittabob IV with Arthur Keeble at the helm but I can't remember the other ECOD. The 30' West Solents (like a Dragon) had a similar rule, ie. sail area 575 sq. ft sloop rig, no tops'l and Roderick Kalberer put a gaff rig on his Vivacious and cleaned up in the East Coast Race. The latest 'star' is Mark Butler with his Etchells 22 high tech gaffer. Goes like excrement off a shovel; tacks through <90 degrees and hard to beat. But at the end of the day, is the comparison important? If it is a question of racing then pointing the boat in the right direction wins races. If cruising, then 'Gentlemen don't beat to windward' as the saying goes. And as for lug rig, that is really efficient. Crab Claw rig is supposed to be the best though but with long spars would increase the cost of a marina berth.

Tom Lathrop
08-26-2000, 08:42 AM
Great discussion! Contrary to the way it may appear, I'm not proposing that the triangular marconi is the most efficient sail. It just seems that the triangle is the easiest way to simulate the ellipse which, I believe, has been proven to be most efficient. A high aspect gaff (if the gaff can be controlled to reduce twist) may well be closer to the ideal than the triangle. It requires a lot more stuff (complication and money) to do it though. Is this the way the boats in the match race were rigged? Fully battened mainsails with lots of roach get closer to the ideal than any rig other than the rigid wingsails.

On a sail area basis, the cat rig is probably most efficient to windward. However sailing a cat rig off the wind in a blow is not for the timid, especially with a gaff where the center of effort is high and way out to leeward. Can you say weather helm or broach?

Ian Wright
08-26-2000, 01:55 PM
Smacksman,
The other ECOD was Nancy, then owned by Shaun Clatworthy (sp?) crewed by Marc Plummer and Peter Brooks, and yes he lost by bad sailing,,,,,,,but he was never going to beat Arthur Keeble was he?
Rob Williamson and I sailed to Ireland and back last year and Holland this year, from the Blackwater,Him in his bermudan Vertue Maid of Tesa and me in my Gaff version Patience. In light airs he would pull ahead but Patience is about a ton heavier than Tesa. In winds of 3 or 4 we are equal to windward but only if I use my top sail. Other things being equal it's luff length that gets you to windward imho. On a reach however Patiences gaff rig makes her much faster, in a five or six VERY much faster. Still Rob tends to win if we really race 'cos he's a better sailor than me. I'm a rotten racer, I don't care enough to win anything,,,,,,,

Ian W

[This message has been edited by Ian Wright (edited 08-26-2000).]

John B
08-26-2000, 07:17 PM
it is a great discussion, and its good to see people exploring options for new boats as well as others doing the right thing by old boats rather than just taking the default road of bermudan. as i said, my old beast goes as well to windward now as she did under cutter bermudan but if i wanted to really perform on our classic yacht racetrack i'd have put an ali stick in with a high aspect bermudan in. a very famous 1902 local boat is going that track as we speak.can't say that i agree with it but thats what they want.
why have something nice when you can have something special.
foster, luff length with topsail set is pretty near any proposed bermudan that i would /could have imagined.
smacksman, yes i read about the etchells....he reshaped the stern into a counter and runs a gaff sloop rig.(if you know him get him to put a bow sprit on for reaching...(looks, really) go on go on double dog dare ya)
ian, i'm going straight to my "classic boat" collection to find your boat ... i'm sure its in there. my boat the waione was on the may cover and there's some photo's in the august issue.
i'm just going to have to go and sand something now and believe me there's pleeeenty .

scottek
08-27-2000, 06:13 AM
An important variable in windward ability of gaff vs. marconi rig is wind speed/strength. A good example is shown in the 8 Meter class. Here is a class that started out as gaff rigged wooden sloops and evolved into modern marconi rigged fiberglass (class rules = no carbon) racing machines. Typically the modern boats rule the water. BUT at a recent world championship (last decade or so), the wind conditions were such that favored the gaff rigg. I believe the winning boat was a marconi rigg, but there were gaff rigged classics in the top ten, ahead of other moderns. Does this mean that the moderns should have switched to gaff rigg for this race? No, their hull design is suited for a particular sail plan, just like the gaff rigged boats have hulls that are matched with their sail plan. Note that the 8 Meter class is based on a class rule, this means that you have varying hull/sail plan designs that can satisfy the rule. One design class boats are different because they are based on a single design, usually hull and sail plan. The one design classes that allow different sailing riggs are set up so that either rigg is equal in competiveness. This equality is in theory because one rigg will typically have the upper hand and the class will usually migrate towards that rigg. The problem is that the class will follow the example of who is winning, and the winners may be winning on better sailing ability reguardless of which rigg is on their boat.

There are alot factors other than windward ability that should influence your descision. Broad reaching/down wind ability? Who cares if you lose a little to windward if you can kick their pants off downwind? Are you looking to race or are you just worried about making it home after a downwind adventure? Are you the type of person that would adjust shroud/stay tension to suite that days wind conditions? Or would you rather set them for the season and just have fun sailing? What are the speed/planning characteristics of your hull? Will you always have a crew, or will you be single handed a significant percentage of the time? Is sailing speed more important than ease of handling? Answer these and other questions and you will have an obvious rigg choice...

Do not forget a very important issue... Rig the boat the way you want. I think that you would be satisfied with the windward ability of either rigg. A 14ft boat is not that costly to change riggs in the future (provided proper sailplan/mast location balance is maintained). You could build both riggs and provide us with experimental data on which rigg you found to be best...

-YF Scott

scottek
08-27-2000, 07:33 AM
Questions for those of you that have sailed similar boats with gaff and bermudan riggs:

What was the aspect ratio (luff/foot) of the bermudan main? Was it significantly different than that of the gaff rigg?

It is said that the higher aspect ratio has better aerodynamic efficiency, thus better windward ability. But there are some inherent problems that greatly effect this advantage. Assuming that the bermudan/marconi rig had a higher aspect ratio sail plan:

What was done to correct for the increased healing moment? More/lower ballast? Need to correct for weather helm? Was there increased leeway as a result of the increased healing moment?

How did the mast and rigging differ between the two boats? Mast turbulence has a detrimental effect on the sail's aerodynamic efficiency. If the mast was not sized and shaped specifically for the bermudan sail plan and to address this turbulence issue, any benefit of this sail plan would be lost.

How distorted were the main sails on the bermudan rig? Increased strain on the sail fabric at the leech causes the sail cloth to distort. Poor leech shape and sail draft cause the sail to lose drive and lift. Inferior sail cloth and worn sails are subject to this distortion, that is why many high tech racers replace their sails very frequently (after every season or even after every race). A perfect example of this situation is seen in the J-24 one design class. With everything else as equal (keel faired, crew ability, etc...), boats with new sails are significanlty (relative to the rest of the fleet) faster than boats with worn distorted sails.

How seaworthy was the sail on the bermudan rigg? Was it meant for a single race/season? Or was it compromised to accomidate a longer useful life? Many high aspect ratio bermudan sail require headboards and batten supported roaches to provide greater area and improved leeches. Battens and headboards can be very destructive sail paraphernalia. Unless the aspect ratio was low enough to not require these features, the sail's durability is compromised and thus has a limited life, or the sail's aerodynamic efficiency was compromised in favor of a more rugged sail.

These questions and design information were taken/paraphrased from a chapter in Emiliano Marino's "The Sailmaker's Apprentice".

-YF Scott

[This message has been edited by scottek (edited 08-27-2000).]

Smacksman
08-27-2000, 03:15 PM
Ian Wright,
If it was Sean Clatworthy and his Nancy against Arthur Keeble in Chittabob IV then it is in my view an even closer match. Sean is a sailmaker, trained under Jim Lawrence of Brightlingsea, and no mean helm. Arthur is a shipwright with more years experience. In my view, the close result of these matches is as good a practical comparison you can get between gaff and bermudan with same hulls and same sail area. From a racing tactics side it is even more impressive for the gaffer to win as the bermudan can dirty wind the gaffer all up the beat and protect his position off the wind by luffing. I sailed my old NY sloop, Emma of Bosham, alongside Maid of Tesa and Rob Williamson (tug forelock at mention of ex-President of the Old Gaffers Association) and you at several Shotley Classic Boat Festivals where bermudans and gaffers raced happily together. I have it on record that you won the odd pot or two in OGA races notwithstanding your modesty regarding your abilities above. Interesting that you say that your tops'l made a difference on a beat. I've found them useless on a beat as with the gaff fallen off relative to the boom the tops'l lifts long before the rest of the sails. If the beat is long enough I have found it pays to strike it and reduce windage (Emma's is a yard tops'l) Mind you, I only use an old jib inverted so it is cut much fuller than most tops'ls but conversely, that fullness really gives some drive when full and bye and freer.
Tom Lathrop, The OCOD's and West Solents mentioned in the match were old (now classic) designs governed by class rules and the aspect ratios of the mains are very low 'leg o muttons' by todays standards though with high peaked gaffs. Cost goes up dramatically with fully battened mains but they are a dream to work with in a blow now that they seem to have sorted out the sticky cars but still chafe problems in the pockets on the ketch I took down to the Canarie Is. last month.
JohnB, You are quite right, there are two camps here; 1. classic and 2. modern and in my view both sub-devided into a. those with money and b. those without. 1a's can accept the challange to keep the old girls as new, 1b's can compromise a bit, have fun and keep the old girls going until a 1a comes along. 2a's have the world to choose from and 2b's improvise and swap ideas. Mark Butler's Spellbound is an Etchells 32 (not 22 as I said before) of 1978 vintage and doesn't need a sticky-out-bit to reach fast as he uses a sweetly cut reaching bag. He's another sailmaker and sure makes his boat go and doesn't have a computer-controlled laser cut facility either. While you are going through your old 'classic boats' take a look at page 5 of Issue No. 63, Sept. '93 and there is yours truely with Emma and a 2.50 genoa having fun!
I need to talk with pictures so I have set up a page called http://emma.datablocks.net/wb/wb.htm with a pic of Emma and Vivacious in gaff and bermudan rig. If anyone wants to put a pic on there for discussion then email it to me as an attachment and I'll pop it up for a while. Please shrink JPEGs to under 50kb or the pics will take a month to load.

John B
08-27-2000, 05:27 PM
smacksman the comment about the bowsprit is tongue in cheek and based on my own personal preferences. i looked for the ecod and found chittabob in a c.b. and what a lovely looking thing it is. i'll give that web site a good look over too.

scottek, counting the gaff as luff length ,i've got about 12 m compared to 8m (um, say 40' to 28')when sailing without a topsail. topsail makes it more like 14 m luff ( say 46 ft to 28 ft) i'm trying hard but i just can't quite get that leading edge figure of 2 to 1. you have to accept that this is my interpretation of an edwardian rig ( heck ,i shortened the boom from a designed length of around 32 ' as it is), so you probably wouldn't choose that sort of ratio for a modern. yes weather helm in this sort of boat is normal with the mast so far forward. whats right on the wind is macho off the wind .
the big negatives of the gaff rig are the increased drag of all that chord and the forestay sag. as you all say though, that is made up for in eased sheets performance and the general glory of it all.
john.

John B
08-27-2000, 07:36 PM
oh the other thing.
i thought i'd heard of them all, but what is a crabclaw rig?

Smacksman
08-27-2000, 08:51 PM
Crabclaw is sort of lateen with yard top and bottom and a scalloped leach. Tony Marjong or whatever the expert's name is waxed mega about how the Polynesians had got this right and produced lif/drag charts to proove it. I'll see if I can dig out some drawings and put it on http://emma.datablocks.net/wb/wb.htm
It was the vortex produced around the spars that increased the lift. Yachting Monthly or similar 10 years back?

htom
08-27-2000, 08:53 PM
Crab claw, I assume, is what I think of as "Polynesian V-shape", although "Polynesian inverted A-shaped" might be more accurate.
Sail has a point near the deck, two peaks up in the sky, with a curved cutout between the two peaks.

Watching some nature program this afternoon, it looks to me like gulls, etc, have wingshapes that are a lot like very-high aspect gaffs, or floppy gunthers. The typical Marconi has an ellipisical trailing edge, but a straight leading edge.

Smacksman
08-27-2000, 08:59 PM
I've just lost a reply so maybe this is a duplicate. Hummmm. Crabclaw rig is an ancient polynesian setup, single sail, yard top and bottom meeting at the tack like sort of lateen, with scalloped leach. Tony Marjong (or similar) waxed mega that lift/drag coefficients were better than any. I'll try and dig it out and put it on my page above.

ACB
08-27-2000, 10:22 PM
our topsail on Mirelle won't stand to windward. However, I think this is the topsail's fault, or the rig's fault. In 1976 my father and I re-rigged our little 18ft tabloid cruiser Mytica from bermuda 3/4 sloop to gaff cutter, keeping the bermudian mast, and setting a yard topsail on it.

We deliberately copied Laurent Giles's gaff rigs with "marconi" masts (Dyarchy's rig is a good example of this) where the peak halyards are taken high up the mast and opposed to a jib stay which is parallel to the forestay. This is rather different to "normal" gaff cutter rig such as Mirelle has.

The rig we drew was checked over by Arthur Dennis of Taylors in Maldon, and the sails were made by that fine firm, now defunct, including Arthur's trade mark mitre cut loose footed main.

She was remarkably close winded; this I am sure was because of the advantageous lead of the peak halyard, a la Laurent Giles prewar gaff offshore racers, the fact that the topsail set well even when hard on the wind, and the vastly better set of the headsails, which really looked like an Illingworth and Primrose yankee over genoa staysail set up.

Now some people will say that this rig is hardly a gaff rig at all, and certainly it includes many drawbacks, but it was at least as close winded, probably better, than the bermudian rig that someone had wished on her. I believe that greater luff tension and less leach twist as compared to Mirelle's classical gaff cutter rig were the factors.

Ken Hall
08-28-2000, 11:39 AM
Okay, said the greenhorn (something like a Block Island Cow Horn but slower http://media4.hypernet.com/~dick/ubb/smile.gif), I have a slightly off-topic question. Is there a different name for the type of rig used on the Mirror 11? The main is definitely a marconi cut, but there's a kind of gaff that gives the extra height, instead of a single tall spar. Looks like a gaff, but I don't think it's intended for use at anything but the vertical. Right now, it just sits in my garage staying dry (inspected every few months), until I decide what and how to replace the long-gone hull.

Ken

Alan D. Hyde
08-28-2000, 01:47 PM
Ken-

Sounds like it might be a gunter rig, once very common for small boats and sailing canoes.

Alan

[This message has been edited by Alan D. Hyde (edited 08-28-2000).]

Smacksman
08-28-2000, 07:58 PM
If the Mirror 11 is a Mirror dinghy as I know it then it is definitly a gunter main. Tens of thousands built worldwide and great for training children to a two man boat with spinnaker. Just had the World Champs in Europe and a local pair from the Deben won.

Paul Schut
08-29-2000, 10:46 AM
The dutch waters where I sail are rife with gaff rigged small (6 to seven metre) daysailers with keels. Most have a high, almost vertical gaff and pretty fair windward performance. Something sleek and high like the Yngling I used to sail would outpoint them by about 10 degrees, but then there is little on the water as good at pointing as an Yngling. For small boats I am very impressed with the cat rig as used on lasers or the Finn I currently sail (and yes It is available in glorious mahogany, being a pre-war design. It is simple to make and rig and has excellent windward performance. I recently built a 6 metre by 60 cm canoe proa to paddle and sail out of ceder/epoxy and use a 5.6 metre sailboard sail to drive it, without wishbone or boom. It has been surprisingly effective (and fast) I am now considering a double cat rig using two unstayed surfboard masts. It might be right for a 14 foot dingy (isnt that what started this all?)

Ian Wright
08-29-2000, 03:16 PM
The Mirror is described as a gunter rig but imo it's bermudan set to a vertical topmast,,,,,,

Smackman,,,,
The race between Arthur and Sean took place during an East Coast OGA race ten (?) years ago. Sean dumped his girlfriend (now wife) Gail on me as extra crew to take Marc and Peter (two noted hired guns) as crew. It was nip and tuck for most of the race but Arthur chose the north bank (Tollesbury/West Mersey) and Shaun the south, (Bradwell) on the beat home. Arthur knows the water very well,,,, He tacked twice, Sean, if you choose to belive his crew, and I do, "about Fifty, we were bloody n****d, and we told him to cover Arthur, but he woudn't listen,,,,,,"
About Chitabob,,,,,, Arthur told me that she was "fast but wet, a bit of a sailing submarine,,, and after every hard race she needed a re-build,,,,,"
During the same race Patience, Sheila, (my wife) Gail and I won the first of the prizes you mention, The Thirslet Spittoon, for spending eight hours on the Thirslet Spit after running aground at the start,,,,,,,,,,

,,,,,,and Sean made Patiences sails btw,,, did a pretty good job too,,,,,,

Hope to be out for a sail this weekend along with Marc Plummer and his Vertue (n.b. for sale) give a wave if you see us,,,,,,,,

Ian W

John B
08-29-2000, 05:21 PM
ref the crab claw....thanks for the lesson, you'd think that the person (probably)closest to polynesia if not in it might know that. i've never heard any name for it actually ,but just associate it with proa's and the like.
ACB you might like to know that we have a "dyarchy" here called sorceress. a very faithfull replica and with a reputation of going pretty well where ever it likes in a race. typical call "starboard" answer "big".
a great yacht owned by a very nice guy. a very powerful sail carrier.

Smacksman
08-30-2000, 04:58 PM
JohnB, What's in a name? :) I couldn't find my old drawings of a Crabclaw rig so sketched one anew and popped it up on http://emma.datablocks.net/wb/wb.htm then read your note above and felt a bit silly as you will know the rig far better than most, being on the ground as it were.

John B
08-30-2000, 05:54 PM
smacksman,
up until last year you could sail all season and never see a gaff rig out here and the probability of seeing a topsail was about zip., same for a crabs claw. the day i set my topsail for the first time' i was feeling smug about it and then noticed 2 other gaff rigs with jackyards set.later on in the season it was downright common. you never know, perhaps we may even see a proa with a crabs claw one day.
john

Smacksman
09-01-2000, 01:22 PM
Paul Schut, You certainly have some beautiful old gaffers in Holland. I picked up a yacht delivery in Enkhuizen (spelling?) the other year and the lovely old harbour there was filled with wooden spars and tarred or varnished hulls. Great place and super friendly locals.

dadadata
09-01-2000, 02:21 PM
<<
My 37ft gaff cutter tacks through 110 degrees.

Don't even think about gaff rig on a 14 footer. If you need short spars, to
stow in the boat, use a gunter lug rig.
>>


Why not? I have a 12-ft sailing canoe/sharpie, cat rigged, 30 sq ft gaff sail. Sails just fine.

dadadata
09-01-2000, 03:11 PM
It's "Marchaj" - Polish.

There's no such thing as a "better rig". There are only "different rigs".

It's a given that racing boats are going to use "Marconi" rigs. That's where all the development money has gone over 75 years.

"Racing" is not a good rationale for saying one sail is "better" than another because the rules make it completely arbitrary. A gaffer is penalized for sail area versus a "marconi".

The "Marconi" actually is around because of materials advances, not because of any inherent superiority. It came about as an effort to have in one sail the equivalent of a gaffer with a topsail over it.

Later Marconi mainsails were encouraged by rating rules due the ay sail area was measured, so once someone could make a tall "marconi" rig stand, the arms race was on.

As far as comapring rigs, actually very little testing under controlled conditions has ever been done. Marchaj and a few others. All the other wind tunnel work has been done by sailmakers who are tunnel visionaries, so to speak, and if it ain't 3 cornered it ain't a sail. There's a very deep conservatism in the sailmaking industry, no matter what they want you to believe.

Only if the next, say, Americas Cup is specified to use gaff rigs will these guys get down and work on it.

In the meantime if you like statistics, stick with baseball, because the stats from yacht races are so crummy it's unbelievable - there are simply too few races and too few boats. not to mention that there are simply too many variables in "big boat" racing.

Maybe we can convince the Optimist Class to switch rigs every two years. That might work to generate some data.

As far as Marchaj and his lateen and crabclaw, you have to read the stuff carefully. The lateen had *no boom* and the rigs were set up without any "gofast" add ons like vangs because the tests were done with third world fishermen in mind. They are usually without Harken gear <chuckle>.

As far as the crabclaw, there are a bunch of different shapes, and no one is very clear on why they work but they do seem to work well.

As for junk rigs, well, again, a surprising amount of work has NOT been done under controlled circumstances. Tom Colvin in the 1960s sailed two identical hulls, one gaff, one junk-rig and reports that performance was to all intents and purposes identical. Only in the past few years has anyone (a grad student) undertaken any wind-tunnel work and as far as I know it's still not completed or published.

Comparing sails to animals isn't very productive, because there are more differences than similarities or as the man once said "correlation does not imply causation."

Someone else said, there's no law that nature has to choose the "most efficient" solution, only the one that's "good enough". So again, comparisons can be misleading.

Fluid dynamics has advanced a great deal in the last, say, decade. Yet a lot of stuff is still not well understood. Most of the sail stuff we refer to was published in the Dark Ages, comparatively speaking. So the jury's still out on all of this.

The answer is, go sailin'.

If you are obsessed with rigs, build 2 identical boats, give one to a friend, and start comparing rigs and compiling statistics. Now that GPSs are cheap and much more accurate you should be able to get some decent data on speed and heading which you can keep records of.

Jim M
09-02-2000, 12:21 AM
Priorities, for non-racers:

1. Easy to handle, especially under difficult conditions
2. simple (cheap & easily repaired)
3. efficient -- most headway for least heeling

Paul Schut
09-04-2000, 05:12 AM
smacksman, I'm glad you enjoyed Enkhuizen (A for spelling, by the way). One of our best designers lives there, Olivier van Meer, did a.o Puffin series and the sail plan for the star clippers, great eye for fast yet sure lines.
The reason you see a lot of gaffs here is practicality, especially on the lakes. Most lake classes have a gaff so you can drop sail and mast quickly if you don't want to wait for the bridge to open. You just power straight at it, drop the spars, drop the relatively short mast and slide through. Outboards, of course are for wimps. All this with 16 to 22 metres of sail (or 160 to 220 sq feet or so). www.knwv.nl (http://www.knwv.nl) has some info on the classes, especially BM16 and Valk, the boat designed for Bruijnzeel multiplex in the 30's to prove you could build boats with it. From www.knwv.nl (http://www.knwv.nl) pick 'zeilen', then 'klassenorganisaties' then 16m2 or Valkenklasse. Have fun with the dutch, fortunately there are pictures!

Paul Schut
09-04-2000, 05:12 AM
smacksman, I'm glad you enjoyed Enkhuizen (A for spelling, by the way). One of our best designers lives there, Olivier van Meer, did a.o Puffin series and the sail plan for the star clippers, great eye for fast yet sure lines.
The reason you see a lot of gaffs here is practicality, especially on the lakes. Most lake classes have a gaff so you can drop sail and mast quickly if you don't want to wait for the bridge to open. You just power straight at it, drop the spars, drop the relatively short mast and slide through. Outboards, of course are for wimps. All this with 16 to 22 metres of sail (or 160 to 220 sq feet or so). www.knwv.nl (http://www.knwv.nl) has some info on the classes, especially BM16 and Valk, the boat designed for Bruijnzeel multiplex in the 30's to prove you could build boats with it. From www.knwv.nl (http://www.knwv.nl) pick 'zeilen', then 'klassenorganisaties' then 16m2 or Valkenklasse. Have fun with the dutch, fortunately there are pictures!

Smacksman
09-04-2000, 04:46 PM
Paul, Thank you for the link to the site in Holland. Great pic of the 16 sq.m 's against a stormy sky. A little bit of Africaans I picked up in South Africa helps with reading the site. I hired a 1935 Norfolk Broads gaff cruiser a few years back and she had a lead counter-weight to her mast for shooting bridges. I didn't have the courage to do it under sail and started the engine. Someone else's boat so I am very cautious. We always have lots of sailors from Holland come over to the east coast here and they are very welcome .. even if they have triangular mainsails! I was told by someone that you might have a New York Sloop in one of your museums; same as my old girl you can see on my un-finished site .. http://emma.datablocks.net/wb/wb.htm
Any info would be welcome.

Paul Schut
09-11-2000, 10:22 AM
smacksman, your Emma is one sexy sloop. I've been oggling the Cornish Shrimper as a family boat (do you know them? a 20 ft sailing shrimper, poly hull, wood decks, looks more like a boat than most) but this one beats it on looks. I understand the tender is the roof for camping purposes? Nice idea.
The lead weight on a mast is one of the usual features on the frisian flat bottom barges that are still raced intensively up here (and you'd be surprised how they go). Having no motor but 80 square metres or so they shot bridges the same way, just two on board. Takes some practice though.

Smacksman
09-11-2000, 03:59 PM
Paul, Cornish Shrimpers and Crabbers very popular here abouts and sail lekker. Bumped my way inside the Friesland Islands the other year. A wild and beautiful area and fun going through the zeegats.

Paul Schut
09-12-2000, 10:34 AM
smacksman, I always knew Dutch was a world language! Re your quest for info:I have not come across anything like your NY sloop in the maritime museums I've been.
Her's some adresses that might help: www.bataviawerf.nl (http://www.bataviawerf.nl) (Batavia yard) www.generali.nl/scheepvaartmuseum (http://www.generali.nl/scheepvaartmuseum) (amsterdam)
and www.mmph.nl (http://www.mmph.nl) (rotterdam museum)
Happy hunting!

Smacksman
09-12-2000, 02:48 PM
Much obliged for the links Paul, I will check them out. Fair winds ...

ishmael
09-12-2000, 03:32 PM
Boy Patrick,

Enough here to fill two or three PHd's in half a dozen discipines each if followed to logical conclusions. I confess to only scanning, and remember this discussion being only an addendum to a discussion that has rowled and raged since the first Bermudian rigs were stepped.

If you aren't goin' to try and go as fast as possible to windward (and who wants to do that except racers, or racers at heart, no fault,) I'd look at the gunter rig. Ease of construction, a compromise performance to windward, stows in the boat for mooring and trailing, eases the weight aloft with a reef, makes reefing simple and positive with no tugging at things stuck, and... there must be a couple more. Enjoy, whatever you do. Ishmael

TomRobb
09-15-2000, 09:05 AM
I've not read most of this thread on purpose. It seemed like the question would generate more heat than light. Lots of good stuff however. As usual.
But, if you really want an engineering/scientific comparison of rigs you'll have to do a fair number of strictly controlled repeatable experiments accounting for ALL variables. Lots of luck. And even if you manage to get decent data, what are you going to do with it? You'll never control all the variables in real life on the water. Make your choice based upon esthetics, habit, a flip of the coin, what you can afford, what ever. Go sailing. Enjoy.

Meerkat
07-21-2003, 01:42 AM
I pulled this back to the top because I had not read it before and it's a fantastically read!

brian.cunningham
07-21-2003, 02:43 PM
You might find Wharram's wingsails interesting that. A gaff with a sleeve luff
http://www.wharram.com/images/GAIA_WINGSAIL.jpg

The 46 ft boats tack through 80 degrees, and they're catamarans, which should be worse!

Even this big cruising cat tacks through 100degrees
http://www.wharram.com/images/Gaia-9806-31.jpg

Dan McCosh
07-21-2003, 03:46 PM
At first glance, the Marconi beats the old-style gaff rig to winward. But then you have to ask what a "gaff" is. Most modern, extreme high-tech rigs are using a long, stiff batten aloft to add area and come close to an eliptical planform, sometimes eliminating the standing backstay. Is this a "gaff" in disguise? i would argue that technically it is, and you end up with a rig that is faster than a Marconi, and even trickier to handle in many wind conditions. How about a gaff at an extreme upright angle, made of carbon fiber? Just thinking....

Wild Wassa
07-21-2003, 04:23 PM
I raced a range of dinghies from 11ft to a 17ft, last season. The rigs are so individual and different in their handling and pointing, between the different boats, that I was caught out a few times, by not knowing the boat's optimum setups vrs angles. Even a 2 inch adjustment to the rake between races (two races each race day), can change the nature of a boat markedly, from first to last.

With the yardsticks of the different dinghies as a guide and looking for rigs as close to 'fully' adjustable as possible, and making a comparison of their sail sizes, it isn't too difficult to see what is very efficient. Considering that gaff rigged dinghies have very little sail area, compared to the other rigs, they are efficient, but not fast.

The Bermudans and Marconis go for speed, while the slower gaff rigs tighten the angles and win (on handicap) twenty minutes later, :mad: .

Warren.

[ 07-21-2003, 06:16 PM: Message edited by: Wild Wassa ]