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Thread: efficiency of the sprit rig

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    Default efficiency of the sprit rig

    I've noticed that the Optimist Pram is rated faster than the El Toro or the Naples Sabot. I recall reading about a French club that tested Optimist Prams with a variety of rigs, and found the sprit the fastest, but I can't find the link anymore.

    There have been various things said about the rig, and I'm wondering, has there been any really reliable work comparing sprit rigs to Bermudian rigs? I've seen some wild claims made, but I'm trying to find reliable information.

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    Default Re: efficiency of the sprit rig

    This should be good
    Steve

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    Default Re: efficiency of the sprit rig

    Considering what a massive job it would be to assemble all the stuff you would need to attempt to make a meaningful test, and all the variables which would need to be addressed to get some sort of half-way accurate answer, I wouldn't hold my breath waiting for the results. It's not at all like just being a matter of letting them roll down a hill to see which one gets to the bottom first. On a certain day, in certain specific conditions, with a certain sailor sailing with a certain style and the rig trimmed a certain way you might be accurately able to claim that one is faster than another. Change one or two of your specifics though, and the whole conclusion likely goes right out the window. A Laser is faster than a Sunfish.....except when it's not - and there are times when it's not.

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    Default Re: efficiency of the sprit rig

    And the tune of an Opti rig has been refined seriously. Might be better to think of as a fat head with a slight disadvantage on one tack.
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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    I've noticed that the Optimist Pram is rated faster than the El Toro or the Naples Sabot. I recall reading about a French club that tested Optimist Prams with a variety of rigs, and found the sprit the fastest, but I can't find the link anymore.

    There have been various things said about the rig, and I'm wondering, has there been any really reliable work comparing sprit rigs to Bermudian rigs? I've seen some wild claims made, but I'm trying to find reliable information.
    One issue is that US Portsmouth ratings are ludicrously unreliable in some instances. The International Moth is rated far slower than a Laser 4.7; even for a Classic the rating can't be right. The International 14's rating is little quicker than that of the 470. Most bizarrely of all, the Laser 4.7 is rated as faster than the Laser Radial which has a 5.7m sail and is disproportionately quicker than the 4.7.

    Here in Oz we have a fair bit of racing between "normal" Sabots and Optis, and the Sabots are quicker and rated accordingly.

    Some of the rig claims are wild, as you say. I remember the one using primitive cats in Southampton or somewhere, which made enormous claims for the speed advantage of the sprit. I think that if you believed the claims, you could put a sprit rig on a Hobie 16 and it would have beaten an Olympic Tornado; a Tornado with a sprit rig would beat a wingmasted C Class cat; and a 470 with a sprit rig would beat a 49er easily.

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    Default Re: efficiency of the sprit rig

    Has anyone re-rigged an Opti to see how she does with a different rig? Seems like they're small enough scale and have uniform enough hulls that it might be practical to build one a bermudian rig, another a standing lug, another a gaff rig, another a balanced lug... Chinese lug? Lateen? Wishbone fat-head?

    Turn 'em loose for a season and see if a consistant trend emerges.

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    Yes CA Marchaj (Southampton university) did a lot of work, some published in Performance Sailing. Practical Boat owner also did so on water testing back in 80/90s.
    Very much to do with the point of sail you are on, off wind you don’t want a high aspect Bermuda rig unless you are in a low drag craft using the apparent wind. This stuff is all somewhere on the net but haven’t time to find it now.



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    Default Re: efficiency of the sprit rig

    You could try looking up the Bembridge Redwing yachts. These are a standard hull and the owners can out any rig they like on the hull provided it does not exceed 200 sq. feet.

    Just about every rig and sail combination under the sun has been tried and raced against other Redwings over the past 117 (that is one hundred and seventeen) years. If any particular rig proved to be so superior that it beat the rest, then the other owners would have changed to that rig. I dare say that the sprit rig would have been tried and experimented with and in the laboratory of the English Channel.

    https://www.bembridgesailingclub.org...sses/redwings/

    http://www.sailingnetworks.com/desig...bridge-redwing

    http://www.cvrda.org/dinghydata/bembridge-redwing/

    My conclusion is that the superiority of a rig depends entirely on the use that you are going to put it to. The sprit rig sets a lot of sail that is easily managed by a small crew (the Thames sailing barges were sprit rigged and handled by a husband/wife team or a skipper and "boy") and the dominance of that rig for that purpose was based on economy. The rig performed well enough that cargo could be moved fast enough and cheaply enough to pay their way.

    Was it the "best"? For its purpose, yes.

    The lug sail was "more efficient" and the smugglers favoured this rig because it was fast and weatherly to evade the Kings customs cutters. Try this source for stirring deeds and adventure:

    http://www.gutenberg.org/ebooks/17563

    But the smugglers were willing to sacrifice everything for speed as the consequences of being caught were somewhat awkward! >};o)

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    Default Re: efficiency of the sprit rig

    I like the sprit rig just fine. . .until it comes to trying to furl it or reef it. I never had much objections to how it worked for basic sailing; it is entirely in the realm of sail handling and handiness to set or strike afloat where I bitterly hate its black-hearted, treacherous nature. For a low-tech, casual dinghy, why not? For a more adventurous sort of boat that doesn't get to sail to the beach every time you need to fiddle with the rig, hell no!

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    Default Re: efficiency of the sprit rig

    The occasional claims that the bermudan is only good upwind and inferior all-round don't bear up when one considers how much ocean racing is on a reach or off the breeze. Some of the tests have been ludicrous, like the old one done at Southampton using primitive cats years ago. It claimed the sprit would drive the boat something like 15% faster than a bermudan.

    That means that a Hobie 14 or 16 fitted with a sprit would beat a 20ft Olympic Tornado; that a 470 (or was it a Laser?) with a sprit rig fitted would beat a 49er, I think; and essentially that every one of the world's racing designers and sailmakers is a complete moron, and that all the professional aerodynamics experts who work with them are also drooling idiots. It's rather astonishing that anyone puts much credence in the test, especially since so many of the world's best sailors, sailmakers and coaches are so well acquainted with the sprit rig from their Opti experience.

    It's interesting to see that some of Marchaj's best known work (about the influence of masts over flow on sails) seems to be collapsing with modern studies. It always seemed odd that he used grossly over-sized masts in his wind tunnel work, and certainly in some of his early books the sails look to be very crude. If anyone thinks I'm being too severe, I'm just discussing Marchaj the way he referred to other people.

    As Phil says, it all depends on the use anyway.

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    Default Re: efficiency of the sprit rig

    There is really no way to make the comparison even between this type of rig vs. that type of rig. For any given hull for example, you could build a lugsail, spritsail, Bermuda sail. etc. which was noticeably faster, or better in heavy (or lighter) air, better in a chop or better in flat water, better with a heavy (or lighter) sailor, or even with a more skilled (or not) helmsman than a differently cut and shaped sail of the same type and square footage, perimeter shape and basic layout. If you're under the impression that all 65 sq. ft. spritsails (for example) sail at the same speed, power, pointing angles, etc. then you still have a lot to learn about sails. The vast majority of us will never get the opportunity to try out and tweak enough different sail types (or sail cuts within a type) to be able to make any particularly accurate statements about what works best - and even if we had that luxury, the chances that the same answer would be true for someone else on the same boat are pretty poor.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    I've noticed that the Optimist Pram is rated faster than the El Toro or the Naples Sabot. I recall reading about a French club that tested Optimist Prams with a variety of rigs, and found the sprit the fastest, but I can't find the link anymore.

    There have been various things said about the rig, and I'm wondering, has there been any really reliable work comparing sprit rigs to Bermudian rigs? I've seen some wild claims made, but I'm trying to find reliable information.
    This is that club fleet at the Brest IFOS
    18optimists.jpg
    I seem to recall that CA Marchaj found the crab claw to do exceptionally well.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: efficiency of the sprit rig

    DSCF2589.jpgI like what Todd Bradshaw posted above. I had Edey & Duff's Shearwater #7 which is the only one of 13 built with a true Yawl rig. All of the others are Cat Yawls, as originally designed by Phil Bolger. The first time I sailed in company with Shearwater #5 (in the North Channel) #5 was not only significantly faster, but pointed something like 10-degrees better when close hauled. There were a number of factors, in addition to #5's Skipper simply being an accomplished sailor. She had assymetric foil leeboards, halyards inside her mast, a battened mainsail, and had been built without the bow centerboard. Following that encounter I embarked on a program to improve my TRUE NORTH's speed. New leeoards incorporated a laminar-flow foil instead of the NACA foils on #5. I removed the bow centerboard case, which was major surgery under the bow. I bought a new main incorporating roach on the leech, supported by 3 battens. The last time we sailed in company with #5, a 10 mile beat across Buzzards Bay from Mattapoisett to the Elizabeth Islands, my #7 was able to finish 100 yards to windward in spite of having started out 200 yards to leeward, and 1/10 mile ahead after starting a few yards aft. We both had a single reef in our mains. The other Skipper later said it was just a case in which my boat suited the conditions better than his. I was very gratified to have seen our modifications work in our favor. The ARDEA was a worthy competitor.

    On another day in that cruise the ARDEA outsailed us once again.

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    Default Re: efficiency of the sprit rig

    The sprit...hmm...used on Thames barges for the crane. Used on crabbers for the quick brail up. Notably an Elf goes sailing with just two 10ft sticks on a 16ft boat.

    Sprit EvoR...



    Well....8.4 sqm...19ft...and its good for 11 knots. With its flexible sprit and mast roller furler it can boast that it preserves full luff length at its first reef even better than a man with a bermudan!
    Last edited by Edward Pearson; 11-06-2017 at 11:17 AM.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Todd Bradshaw View Post
    A Laser is faster than a Sunfish.....except when it's not - and there are times when it's not.
    Todd's quite right IMO. The variables are too many to get a good comparison that applies in all situations. I was sailing a Sunfish against my neighbor in his Laser and found just what Todd mentions. We'd both been on the same sailing team in college, so I'd say we are equally good at sailing yet I now outweigh him by about sixty pounds. Neither of us needed to hike out, however. We were both surprised at the result.
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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    One issue is that US Portsmouth ratings are ludicrously unreliable in some instances. The International Moth is rated far slower than a Laser 4.7; even for a Classic the rating can't be right. The International 14's rating is little quicker than that of the 470. Most bizarrely of all, the Laser 4.7 is rated as faster than the Laser Radial which has a 5.7m sail and is disproportionately quicker than the 4.7.

    Here in Oz we have a fair bit of racing between "normal" Sabots and Optis, and the Sabots are quicker and rated accordingly.

    Some of the rig claims are wild, as you say. I remember the one using primitive cats in Southampton or somewhere, which made enormous claims for the speed advantage of the sprit. I think that if you believed the claims, you could put a sprit rig on a Hobie 16 and it would have beaten an Olympic Tornado; a Tornado with a sprit rig would beat a wingmasted C Class cat; and a 470 with a sprit rig would beat a 49er easily.
    I've seen that. It didn't look credible. Even if you used their own charts, they didn't support the claims made in the text. Do you have a link to the Australian Portsmouth numbers?

    I don't think the rating in the U.S. tables for the Moth is for a modern one at all. The Europe dinghy, which is essentially a Moth, rates much faster, and about where I'd expect to see a good classic Moth rated.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Peerie Maa View Post
    This is that club fleet at the Brest IFOS
    18optimists.jpg
    I seem to recall that CA Marchaj found the crab claw to do exceptionally well.
    Do you have a link to what they found out? This is the test I was thinking of. There is some controversy about how reliable the tests Marchaj conducted were.

    Having sailed with a sprit rig on numerous occasions, I don't think it points as well to windward as a Bermudian sail, and in any case, the Opti has a quite different hull than the El Toro and Sabot.

    Todd, I've always thought the Sunfish sail was more like a crabclaw than a Mediterranean lateen. In fact, the crabclaw in Nick's picture reminds me a little of how racing Sunfish carry their sail.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    Do you have a link to what they found out? This is the test I was thinking of. There is some controversy about how reliable the tests Marchaj conducted were.

    Having sailed with a sprit rig on numerous occasions, I don't think it points as well to windward as a Bermudian sail, and in any case, the Opti has a quite different hull than the El Toro and Sabot.

    Todd, I've always thought the Sunfish sail was more like a crabclaw than a Mediterranean lateen. In fact, the crabclaw in Nick's picture reminds me a little of how racing Sunfish carry their sail.
    Sorry no. They were just at the end of the same pontoon that we were moored to. The boats were either abandoned or away being sailed by some fearless kids.
    Bermudians will point better to windward, but you cannot sail everywhere into the wind. The chart in tink's post #7 indicates that a gaff, lug, spritsail will perform well over a wider range of points.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: efficiency of the sprit rig

    there are so many variables there is really no way to make a comparison
    Indeed, and especially when the issue of sail shape is not even raised or discussed, which certainly must be considered a relevant variable when evaluating the concept of "efficiency."

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Peerie Maa View Post
    Sorry no. They were just at the end of the same pontoon that we were moored to. The boats were either abandoned or away being sailed by some fearless kids.
    Bermudians will point better to windward, but you cannot sail everywhere into the wind. The chart in tink's post #7 indicates that a gaff, lug, spritsail will perform well over a wider range of points.
    The reason they had the Optis rigged all different ways was an attempt to compare the different rigs. I read their results years ago, and can't remember much, except that the sprit, Bermudian, and crabclaw rigs seemed to do well. They had one rigged with a square sail, which was weather bound at the lee mark.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    They had one rigged with a square sail, which was weather bound at the lee mark.
    Not surprised if they left the mast in the forward step. Should have moved the mast back to midships.
    Compare this to

    Both practically identical hulls.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by tink View Post
    Yes CA Marchaj (Southampton university) did a lot of work, some published in Performance Sailing. Practical Boat owner also did so on water testing back in 80/90s.
    Very much to do with the point of sail you are on, off wind you don’t want a high aspect Bermuda rig unless you are in a low drag craft using the apparent wind. This stuff is all somewhere on the net but haven’t time to find it now.



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    Is that for true wind, rather than apparent? Because most boats don't sail within 20 degrees of the wind, and only the highest aspect sail has any angles of attack noted.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Peerie Maa View Post
    Not surprised if they left the mast in the forward step. Should have moved the mast back to midships.
    Compare this to

    Both practically identical hulls.
    That was one of the problems I had with that test. They had one highly-developed rig, the sprit, compared to a bunch of rigs that were the best they could do quickly. When the Norwegian fishing fleet was changing from square sails to sprit, they had a regatta where the square sails cleaned up -- the fishermen knew how to get the best from the square sails.

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    Default Re: efficiency of the sprit rig

    Yes, I've read that thread, and I'd seen the article before. I was hoping someone had done more definitive work.

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    Default Re: efficiency of the sprit rig

    I know it's controversial, but when I read Marchaj I'm often struck by how his theories contradicted what was proven in reality. I'm just reading his remarks about 12 Metre spinnakers, which the Americans proved to be incorrect.

    In "Sailing Theory and Practice" Marchaj used a bermudan main of 4% draft (extremely flat) with a mast of .375" on a foot of 9.67 to 13.18". That's completely disproportionate. Even a Laser, for example, has a 63mm lower mast which is almost exactly half of Marchaj's test mast. He set draft at 15% aft, instead of the 30-50% that is normally considered efficient. And from some pics I've seen, the sails were also very twisted (as well as being roachless, which would further accentuate the disproportionate mast size and draft position).

    So how did gaffers and other low aspect boats perform in their heyday? Well, my trusty copy of the 1939 CCA rule shows that even in a largely reaching race like the Bermuda, the gaffers could carry an extra 3% more sail area than bermudans, while gaff schooners could carry no less than 10% extra sail area. So, given that sort of huge benefit, the schooners and gaffers would obviously win downwind races at least if they were as fast as Marchaj claimed - but they didn't. The bermudan rigs were starting their long string of victories. Even the Transpac in that era was won by a Bermudan rig.
    Last edited by Chris249; 11-06-2017 at 06:06 PM.

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    Default Re: efficiency of the sprit rig

    Now you've revived that, I see that my earlier comment about the test was far too kind. A few quick calculations indicate if the test results were right, you could drop an Optimist rig (just 3.3m2) into a Laser and it would beat an International Canoe, 505, and 29er upwind and finish with a Flying Dutchman. If you changed a Hobie 16 to sprit rig, apparently it would beat the foiling Nacra 17 Olympic class cat, the ultralight foiling A Class cat, and the Tornado upwind.

    The article was replete with lies, ignorance and insults. It claimed, for example, that the merits of each rig is based on "hearsay and very subjective comparisons" which is an insult to the many sailors of earlier times who actually got out and tested the rigs, one against each other. They claim that no one ever tested different rigs on identical hulls, which is an outright lie or at the very least indicates that they were too lazy to do any research.

    If the authors were just ignorant it would be one thing, but they are insulting to sailors of this and other eras.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    The article was replete with lies, ignorance and insults. It claimed, for example, that the merits of each rig is based on "hearsay and very subjective comparisons" which is an insult to the many sailors of earlier times who actually got out and tested the rigs, one against each other. They claim that no one ever tested different rigs on identical hulls, which is an outright lie or at the very least indicates that they were too lazy to do any research..
    I would point out the Bembridge Redwings as doing exactly that - a standard and highly restricted hull with any rig you liked sailed in the English Channel under an exceedingly wide range of weather and sea conditions. If ypou have a redwing hull and wanted to mount three masts - a Chinese junk foresail, a Flettner rotor main and a dipping lug mizzen the rules said "have at it and fill your boots". They have been experimenting like this for 117 years.

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    Default Re: efficiency of the sprit rig

    Jolie Brise did very well in offshore races with her gaff rig, and as recently as 1932, a gaff schooner was the overall winner in a Bermuda race that included Dorade. A gaff ketch won the TransPac as recently as 1951. But those boats couldn't carry as large a spinnaker as the masthead rigged Bermudian boats.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Phil_B View Post
    I would point out the Bembridge Redwings as doing exactly that - a standard and highly restricted hull with any rig you liked sailed in the English Channel under an exceedingly wide range of weather and sea conditions. If ypou have a redwing hull and wanted to mount three masts - a Chinese junk foresail, a Flettner rotor main and a dipping lug mizzen the rules said "have at it and fill your boots". They have been experimenting like this for 117 years.
    Have they done much experimenting lately? The fleets seem to have pretty uniform rigs now.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    Jolie Brise did very well in offshore races with her gaff rig, and as recently as 1932, a gaff schooner was the overall winner in a Bermuda race that included Dorade. A gaff ketch won the TransPac as recently as 1951. But those boats couldn't carry as large a spinnaker as the masthead rigged Bermudian boats.
    I didn't mean to be criticising the other rigs, which are very useful and attractive. It's just that they normally benefited from being allowed to carry more sail for the rating. Lee Loomis' 'Ocean Racing' reckons the gaff schooners had a 10% rating cut, rather than just a 10% cut in the measured sail area. As late as the '60s, gaff sloops got to carry 6% more sail than bermudan rigs under the RORC rule. Under the CCA rule, the gaff topsail counted just 60% of its area, while the gaff mainsail seems to have counted just 90% of its area compared to 100% for a bermudan rig, AND got an allowance for the lower aspect ratio on top of that. While the gaffers carried smaller spinnakers, it seems from the rules that they would get an allowance for that.

    So with no disrespect for the gaff and schooner rigs, their efficiency (in terms of speed for area, at least) was lower and their success was probably largely as a result of that.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    Have they done much experimenting lately? The fleets seem to have pretty uniform rigs now.
    It looks to me that most classes with measured sail area but free rigs otherwise as well as no limit rigs have moved to similar rigs, ''gaff'' mains aka fat heads where there is some kind of diagonal batten ("gaff") supported by single a peak/ throat ( a triangle of sail cloth). Certainly this is the way of the internatonal canoes. This is really kind of a silly discussion.
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    Default Re: efficiency of the sprit rig

    In boats less then 22 ft. Gaff or gunter rig was always more popular, also in races. Boats that tried bermuda often changed to gaffs when racing in Holland. I understand the same happenedto the Herreshoff 12 1/2 and later Joel White Havens.
    I think the difference in speed is small. But in bigger boats it is harder to build a mast without spreaders so a high aspect gaff rig is harder to make. Frank

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Ben Fuller View Post
    It looks to me that most classes with measured sail area but free rigs otherwise as well as no limit rigs have moved to similar rigs, ''gaff'' mains aka fat heads where there is some kind of diagonal batten ("gaff") supported by single a peak/ throat ( a triangle of sail cloth). Certainly this is the way of the internatonal canoes. This is really kind of a silly discussion.
    Looks more like a sprit rig to me:



    ...but I really think this is a different rig, much more dependent of battens than a true sprit rig.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    I didn't mean to be criticising the other rigs, which are very useful and attractive. It's just that they normally benefited from being allowed to carry more sail for the rating. Lee Loomis' 'Ocean Racing' reckons the gaff schooners had a 10% rating cut, rather than just a 10% cut in the measured sail area. As late as the '60s, gaff sloops got to carry 6% more sail than bermudan rigs under the RORC rule. Under the CCA rule, the gaff topsail counted just 60% of its area, while the gaff mainsail seems to have counted just 90% of its area compared to 100% for a bermudan rig, AND got an allowance for the lower aspect ratio on top of that. While the gaffers carried smaller spinnakers, it seems from the rules that they would get an allowance for that.

    So with no disrespect for the gaff and schooner rigs, their efficiency (in terms of speed for area, at least) was lower and their success was probably largely as a result of that.
    When I was trying to understand the IOR, I tried designing a gaff rig to fit the rule. Gaff peaked no higher than 70 degrees, when real gaffers are more likely to be peaked at 45, no compensation for an aspect ratio less than 2:1 when most gaffers have at best 1:1. I'm thinking the low aspect ratio wasn't really compensated in most rules.

    That said, there were real advantages to the Bermudian rig, like a longer luff, taller mast that would carry a larger spinnaker, ease of handling with fixed backstays. I'm not nostalgic about the rigs, I'm just curious, now that so many rigs have gone with a square head, like the Merlin Rockets and I-14s.

    There are other factors. Yes, a high-aspect rig gives you a better lift-drag ratio close-winded, but it has a higher CE. Maybe you can carry a bigger rig with the old low-aspect rigs and not have to carry light kites to go fast on a reach. If the goal is not efficiency per square foot, but efficiency for effort, are there possibilities for the sprit rig?

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