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Thread: efficiency of the sprit rig

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    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?
    What do you mean with"efficiency for effort"? Otherwise very interesting thread. I think threaddrifting is permitted here, anyway sailmakers use the same Prosail program for every 4 cornered sail, sprit, lug and gaffsail.
    I think lugsails offer more possibilities for improvement than spritsails: usually you hoist a lugsail like a gaffsail so battens can be used while you want to wrap a spritsail around the mast after taking the sprit out.
    Bolger thinks a dipping lugsail is very efficient because the mast spoils the airflow less as it is farther away from the sail. At least one designer made plans for A framed masts or masts like a hoop with the yard and sail freehanging. (Is this english?). It means one could use balanced lugsails without the usual disadvantages. Frank8

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by FF View Post
    What do you mean with"efficiency for effort"? Otherwise very interesting thread. I think threaddrifting is permitted here, anyway sailmakers use the same Prosail program for every 4 cornered sail, sprit, lug and gaffsail.
    I think lugsails offer more possibilities for improvement than spritsails: usually you hoist a lugsail like a gaffsail so battens can be used while you want to wrap a spritsail around the mast after taking the sprit out.
    Bolger thinks a dipping lugsail is very efficient because the mast spoils the airflow less as it is farther away from the sail. At least one designer made plans for A framed masts or masts like a hoop with the yard and sail freehanging. (Is this english?). It means one could use balanced lugsails without the usual disadvantages. Frank8
    If you accept Ben's perspective, the spritsail benefits from full-length battens as well.

    What I mean about efficiency for effort is that a low-aspect sail could require less hiking for a given amount of power, and might perform well enough on reaches that you wouldn't need a light kite to get the boat moving.

    That said, I've been looking at some Woods Hole spritsail boat plans, and they show very tall sprit rigs. The workboats carried about 90 square feet of sail, the racers carried about 130, and the rule was that the sale would be loose footed and sheeted at the transom. They could only increase the power of the rig by putting the mast farther forward or making the mast taller, and the first option was exhausted pretty quickly.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    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?
    Hmm, I wasn't aware of the limitations of the aspect ratio corrections. I may check my CCA and RORC rule copies. It still seems from looking at the rules that the spinnaker hoist issue would have been addressed by the measurements. But it seems clear that even if the CCA and RORC had suffered from similar aspect ratio measurement limitations, IF the gaff was as efficient as the bermudan then the 3-10% extra area that was allowed would have made it unbeatable.

    I'm not a complete fan of high aspect rigs myself. I've got a couple (on the Int Canoe and the Formula 18 cat) and also some low aspect rigs (Windsurfer One Design, Laser, etc) and it's interesting to see the issues that high aspect rigs have at the wide angles of attack we often have to sail in less than ideal conditions. The Laser has similar wetted surface to the Canoe, greater beam and a shorter waterline yet it's accepted that in light airs downwind the Nethercott IC was basically no quicker than the Laser, probably because the rig's high aspect ratio cancelled out the extra area.

    But if the bermudan rig's advantage was all aspect ratio, classes like the Stars and the early Metre boats surely would not have shifted from gaff to bermudan of the same (or nearly the same) aspect ratio and found improved performance? It's interesting to read in Elder's book on the Stars and Dear's book on the Js that a significant advantage of early bermudan rigs was the lower cost and hassle with the use and maintenance of the bermudan sails.

    To me, the square head bermudan sails show that you can have the aerodynamic benefits of the square-top outline in a bermudan without having to drag a spar around. And after years of experience, I'm not at all sure that they work well unless you have good cloth and an efficient boat, because a squaretop with deep draft will suffer from choking of the leach very easily in lulls unless someone is trimming it quite hard. On the other hand, they are great in boats with film sails and efficient hulls that allow the head to be flat enough.

    There's some interesting info about the low aspect gaff rigs and their efficiency downwind in a very old piece by Colin Ratsey. I'll dig it out later but I'm leaving for a few days of staying on the J/36 while patching and moving the timber 28'er. Cheers

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by FF View Post
    Bolger thinks a dipping lugsail is very efficient because the mast spoils the airflow less as it is farther away from the sail.
    Recent aerodynamics studies have shown that the mast is not a hindrance to airflow, as was often thought in the past. In fact it can be a useful way to make the entry more forgiving.

    If Bolger was correct, then why did (for example) almost the entire fleet of British small development-class yachts move away from the lug to the gaff and thence to the bermudan? Why did the workboat-type racers of Victoria in Australia do the same?

    The only dipping lugsail I've sailed with is that of the Italian-rules International 12, which is the most popular racing dipping lug in the world by far. It was very, very convenient to rig and would have been great for the boat's dual purpose as a tender, but even in a boat designed with modern high-tech lines and Harken kit, the necessity to whack the yard over every time you wanted full efficiency was a noticeable extra load compared to tacking a bermudan. Lovely boat, though, and the rig clearly has good properties of its own.

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    Default Re: efficiency of the sprit rig



    Here's a picture of the evolution of the Star rig from Juan Baader's The Sailing Yacht. As you can see, the pole-masted rig had less windage and weight, but they didnt' see enough advantage from that, and went with a taller rig with a shorter boom very quickly. The low-aspect rig was fine if you weren't going to hike out much, but as they quickly started racing the boats, they wanted more power.

    It can be very difficult to keep a straight luff on a lugsail in a strong wind, and if you don't, the sail gets deeper as the wind gets stronger. Pretty much the opposite of the bendy rig.

    I can think of another reason most boats abandoned the gaff rig, it took more manpower to operate it. And early on, I don't think there was any advantage given by the rating rules. I think the Bermudian rig is more efficient than the gaff rig, and as that became recognized, gaffers were given an a handicap advantage. But if you have two rigs which sail their rating and one requires a lot more work to get the best out of it, which would you choose? That's part of the reason this thread isn't about a gaff rig with topsail.

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    Default Re: efficiency of the sprit rig

    Coming back around a bit to something Todd Bradshaw said about what effect the actual cut of an individual sail has compared to another with the same outside dimensions, how was sailcloth technology evolving during this time of transition?
    Steve

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by stromborg View Post
    Coming back around a bit to something Todd Bradshaw said about what effect the actual cut of an individual sail has compared to another with the same outside dimensions, how was sailcloth technology evolving during this time of transition?
    Which time did you have in mind?

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    Default Re: efficiency of the sprit rig

    My grasp of sailing history isn't particularly strong, that's why I'm here asking

    So let's look at the Star Class from 1911 to 1929. Was there some fabric technology that came out of the first World War that helped with the development of the high-aspect rig? Evolution of a technology doesn't happen in a vacuum, one discovery tends to lead to another.
    Steve

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by stromborg View Post
    My grasp of sailing history isn't particularly strong, that's why I'm here asking

    So let's look at the Star Class from 1911 to 1929. Was there some fabric technology that came out of the first World War that helped with the development of the high-aspect rig? Evolution of a technology doesn't happen in a vacuum, one discovery tends to lead to another.
    Well, there was considerable work being done on Marconi rigs, which I suppose you could relate to the stress analysis developed for WWI aircraft. Starling Burgess, for example, was working on aircraft design during the war.

    On the other hand, as racing got more intense, they may just have been willing to lose more masts.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    Well, there was considerable work being done on Marconi rigs, which I suppose you could relate to the stress analysis developed for WWI aircraft. Starling Burgess, for example, was working on aircraft design during the war.

    On the other hand, as racing got more intense, they may just have been willing to lose more masts.
    The critical construction bit that came out of aircraft was the ability to work with light wire in ways that didn't require splices around masts. And looking hard at spreader concepts. The idea of tang rigging. At MIT is the blueprint I found that shows the modification that LFH made to one of Frank Paine's R boats that called for tangs rather than splices. There may be something on it in Roger Taylor's first volume.
    Ben Fuller
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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by FF View Post
    What do you mean with"efficiency for effort"? Otherwise very interesting thread. I think threaddrifting is permitted here, anyway sailmakers use the same Prosail program for every 4 cornered sail, sprit, lug and gaffsail.
    I think lugsails offer more possibilities for improvement than spritsails: usually you hoist a lugsail like a gaffsail so battens can be used while you want to wrap a spritsail around the mast after taking the sprit out.
    Bolger thinks a dipping lugsail is very efficient because the mast spoils the airflow less as it is farther away from the sail. At least one designer made plans for A framed masts or masts like a hoop with the yard and sail freehanging. (Is this english?). It means one could use balanced lugsails without the usual disadvantages. Frank8
    I've found that most commercial sailmakers using sail design programs, make the lugsails and gaffers with the head far too flat. Even when I've gone over the sail plan with the sailmaker I get the same result. Thats ok until the sail is reefed then its way underpowered.
    The sailmaker who builds my sails, and some for my clients lays them out by hand, no computer program, just an accurate eye and lots of experience. Very good sails.
    http://reallysimplesails.com/really-...now-available/

    John Welsford
    An expert is but a beginner with experience.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    Recent aerodynamics studies have shown that the mast is not a hindrance to airflow, as was often thought in the past. In fact it can be a useful way to make the entry more forgiving.

    If Bolger was correct, then why did (for example) almost the entire fleet of British small development-class yachts move away from the lug to the gaff and thence to the bermudan? Why did the workboat-type racers of Victoria in Australia do the same?

    The only dipping lugsail I've sailed with is that of the Italian-rules International 12, which is the most popular racing dipping lug in the world by far. It was very, very convenient to rig and would have been great for the boat's dual purpose as a tender, but even in a boat designed with modern high-tech lines and Harken kit, the necessity to whack the yard over every time you wanted full efficiency was a noticeable extra load compared to tacking a bermudan. Lovely boat, though, and the rig clearly has good properties of its own.
    The evolution of rigs in racers, has more to do with the courses than anything else. A Marconi rig will usually outrun others upwind and thats all important in racing on an Olympic type course, but as an all round cruising rig the gaff or lugsail has a lot going for it. They're faster reaching and running so dont need complex extras such as spinnakers and reachers, have a lower center of effort so heel the boat less for a given amount of drive, and generally stress the boat less.

    John Welsford
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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Ben Fuller View Post
    The critical construction bit that came out of aircraft was the ability to work with light wire in ways that didn't require splices around masts. And looking hard at spreader concepts. The idea of tang rigging. At MIT is the blueprint I found that shows the modification that LFH made to one of Frank Paine's R boats that called for tangs rather than splices. There may be something on it in Roger Taylor's first volume.
    Thanks for the added detail. I think the use of lenticular rod rigging came out of the aircraft industry, as well. Not that any but the most high-end boats ever used it.

    Those advances, and better glues for making hollow masts, allowed for taller rigs to be developed. Plus, a cheaper process for producing aluminum eventually revolutionized spars.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by john welsford View Post
    The evolution of rigs in racers, has more to do with the courses than anything else. A Marconi rig will usually outrun others upwind and thats all important in racing on an Olympic type course, but as an all round cruising rig the gaff or lugsail has a lot going for it. They're faster reaching and running so dont need complex extras such as spinnakers and reachers, have a lower center of effort so heel the boat less for a given amount of drive, and generally stress the boat less.

    John Welsford
    I think that just about sums it up spot on. I am curious as to why? Surely the lower aspect sails are still operating at laminar flow reaching so what happens to all the end losses that higher aspect ratios are supposed to reduce. Perhaps it is something to do with lower aspect ratio rigs having longer cord therefore more distance for the air to travel per unit of area.

  15. #50

    Default Re: efficiency of the sprit rig

    Sails aren't all about maximising lift. On a reach both the lift and drag of a sail contribute towards forward motion. There is a great comparison between sail and wing in "the 40-knot sailboat" by Bernard Smith.*

    Of course for very fast boats you are effectively always going upwind so this probably applies less.

    Quote Originally Posted by tink View Post
    I think that just about sums it up spot on. I am curious as to why? Surely the lower aspect sails are still operating at laminar flow reaching so what happens to all the end losses that higher aspect ratios are supposed to reduce. Perhaps it is something to do with lower aspect ratio rigs having longer cord therefore more distance for the air to travel per unit of area.
    *EDIT: Actually I explained that wrong. The point is that the resultant force still points in a more forward direction. In a plane, all forces are effectively relative to the direction of travel of the plane. On a boat, the forces are all relative to the wind direction, which is not aligned with the boat direction of travel. The upshot is that L/D ratio is not as big a deal on anything other than a beat.
    Last edited by tdem; 11-09-2017 at 04:19 AM.

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    Default Re: efficiency of the sprit rig

    On a side issue this report recently popped up on social media about how life is nothing to do with speed change as many believe. Myself included until I watched the video http://www.cam.ac.uk/research/news/h...gs-really-work

    There is still a challenge in pressure so fundamentally no change

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by john welsford View Post
    I've found that most commercial sailmakers using sail design programs, make the lugsails and gaffers with the head far too flat. Even when I've gone over the sail plan with the sailmaker I get the same result. Thats ok until the sail is reefed then its way underpowered.
    The sailmaker who builds my sails, and some for my clients lays them out by hand, no computer program, just an accurate eye and lots of experience. Very good sails.
    http://reallysimplesails.com/really-...now-available/

    John Welsford
    I do not design my sails but rely on a sailmaker who is trained by one of the best sailmakers in The Netherlands. He designs the sails and cuts the panels for me, and I build the sail from that on. You can see in the video 'Two luggers at play' that my sail (on the 'Lucia) has a nice curve around the upper leach batten. I just changed that batten for a tapered one because the forward end poked in the sail. Now it is better.
    In our small country there are hundreds of gaffers and the best sailors are also racing them, so a sailmaker who is not up to it cannot stay in business. I myself was aboard a sailing barge last weekend during the 'Waddenrace' . A 100 year old steel flatbottomed freighter, nice polyester sails, vertical cut as is custom but with leach battens,dyneema halyards, the race lasted just over 15 hours with one 4 hour stop. At times we did 11 knots, we won, 9 minutes later nr2 arrived. Boat name 'Overwinning'. Means 'Victory', in this case a good name cause it wins often. i better sop now. Frank

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    Default Re: efficiency of the sprit rig

    Here's a link to that vid:



    I've been very impressed with the power of balanced lugs for reaching. Sprits might be a little more weatherly.

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    Default Re: efficiency of the sprit rig

    I've found that most commercial sailmakers using sail design programs, make the lugsails and gaffers with the head far too flat. Even when I've gone over the sail plan with the sailmaker I get the same result. Thats ok until the sail is reefed then its way underpowered.
    A good deal of this is often due to the fact that the program (or its operator) doesn't have an adequate grasp of the concept of spar bend (yard bend in particular). I'm not even sure that some of the computer sail design software programs consider it at all, which pretty much will guarantee failure to perform much of the time. If you look at something like this balanced lug's profile, you can see the bend in the yard in just moderate winds. That amount of curve is equal to, or possibly even more than the amount of head round which would normally be added up there to create upper sail draft. If you don't allow for some bend and build some excess round into the head of the sail, a wind like this would just bend the yard and take all the draft out of the sail's upper area. If you do build in adequate bend allowance, the yard can bend a bit, as you see here, without distorting the sail's top and losing all of its draft up there.

    Naturally, like everything else in sailing, bend is a compromise. Too much added round may make for great heavy air performance when the spar is bending a lot, but then the same sail may be too drafty in light air when the yard is bending less, the excess cloth is making unwanted draft and you would rather have a flatter sail. There are no hard and fast formulas for addressing spar bend, which may make it difficult to program in. However, not allowing for bend at all is a mistake, not a compromise.



    Frank, That's a very pretty boat, though I'm not sure why your sail needs battens at all (especially the top one). Most similar sails will do just fine without them, and if it is cross-cut you can even tuck in a couple small leech broadseams if needed to firm-up the leech

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Todd Bradshaw View Post
    A good deal of this is often due to the fact that the program (or its operator) doesn't have an adequate grasp of the concept of spar bend (yard bend in particular). I'm not even sure that some of the computer sail design software programs consider it at all, which pretty much will guarantee failure to perform much of the time. If you look at something like this balanced lug's profile, you can see the bend in the yard in just moderate winds. That amount of curve is equal to, or possibly even more than the amount of head round which would normally be added up there to create upper sail draft. If you don't allow for some bend and build some excess round into the head of the sail, a wind like this would just bend the yard and take all the draft out of the sail's upper area. If you do build in adequate bend allowance, the yard can bend a bit, as you see here, without distorting the sail's top and losing all of its draft up there.

    Naturally, like everything else in sailing, bend is a compromise. Too much added round may make for great heavy air performance when the spar is bending a lot, but then the same sail may be too drafty in light air when the yard is bending less, the excess cloth is making unwanted draft and you would rather have a flatter sail. There are no hard and fast formulas for addressing spar bend, which may make it difficult to program in. However, not allowing for bend at all is a mistake, not a compromise.



    Frank, That's a very pretty boat, though I'm not sure why your sail needs battens at all (especially the top one). Most similar sails will do just fine without them, and if it is cross-cut you can even tuck in a couple small leech broadseams if needed to firm-up the leech
    Thanks for the compliment, Todd. I have 2 reasons for the battens:1; A roach allows better twisting, 2; I think that with a roach the tension parallel to the leach is shared by far more fibers, and the sail shape has a longer life.
    On our catamaran, the jib developed a hook to windward, so I have to play the leach line, while the main keeps its shape: I never had to tighten te leachline. The main is fully battened and the jib wihout battens.
    But I may be wrong here, and the other boat, grey hull , black upper strake has no battens. And because the boat is a bit overcanvassed I might make a new smaller mainsail, crosscut and battenless. And then I hope to have a chance to discuss these topics with other sailmakers.
    Another thing about twist: A client of mine, builds many luggers like Tirrik, thinks that a balanced lugrigged boat is often faster with the sail pressed against the mast. That way it twists better was his explanation. I am curious if other lugsailors can agree.
    And computer programs allow for the round in any side of the sail, but I think here sailmakers underestimate the bending yards of lugsails because they are used to gaffs that are hoisted on 3 points. And they often do not reinforce the luff.
    Frank

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by FF View Post
    A client of mine, builds many luggers like Tirrik, thinks that a balanced lugrigged boat is often faster with the sail pressed against the mast. That way it twists better was his explanation. I am curious if other lugsailors can agree.
    Frank
    One would say there are hundreds of examples that indicate that your client is wrong. These examples are the racers of world's most popular lug-rigged racer, the (former) International 12 Foot Dinghy. They can get up to 180 or so (IIRC) boats to regattas, it's a major class in the Netherlands and Italy, and they have dipping lugs in which the mast is to windward.

    There's no logical way in which these hundreds of sailors, who race against each other week after week and therefore have innumerable chances to try each side (and have had for a century) could be wrong.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post


    Here's a picture of the evolution of the Star rig from Juan Baader's The Sailing Yacht. As you can see, the pole-masted rig had less windage and weight, but they didnt' see enough advantage from that, and went with a taller rig with a shorter boom very quickly. The low-aspect rig was fine if you weren't going to hike out much, but as they quickly started racing the boats, they wanted more power.

    It can be very difficult to keep a straight luff on a lugsail in a strong wind, and if you don't, the sail gets deeper as the wind gets stronger. Pretty much the opposite of the bendy rig.

    I can think of another reason most boats abandoned the gaff rig, it took more manpower to operate it. And early on, I don't think there was any advantage given by the rating rules. I think the Bermudian rig is more efficient than the gaff rig, and as that became recognized, gaffers were given an a handicap advantage. But if you have two rigs which sail their rating and one requires a lot more work to get the best out of it, which would you choose? That's part of the reason this thread isn't about a gaff rig with topsail.
    The Stars did see enough advantage from the 'short bermudan" rig so that when they were allowed in 1921, to quote Elder who was there"the good skippers, who did not start off with a Marconi, changed to it before 1921 was over".

    I'm not sure which of two rigs I'd go for. Sometimes I like rigs that require a bit more tweaking.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by john welsford View Post
    The evolution of rigs in racers, has more to do with the courses than anything else. A Marconi rig will usually outrun others upwind and thats all important in racing on an Olympic type course, but as an all round cruising rig the gaff or lugsail has a lot going for it. They're faster reaching and running so dont need complex extras such as spinnakers and reachers, have a lower center of effort so heel the boat less for a given amount of drive, and generally stress the boat less.

    John Welsford
    But many of the great offshore races aren't around Olympic courses. The Bermuda, Transpac, round the world and many other offshore races are mainly about reaching or running, and still bermudan rigs perform better. At a guess the Fastnet and Hobart are 33% upwind. That would indicate that the events that for years dominated the offshore racing world were far from upwind biased.

    Is there any evidence that in real life the lug or gaff are actually significantly faster on the reaches, or fast enough to be able to do without spinnakers or reachers?

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    Default Re: efficiency of the sprit rig

    The tall sticks along with the appropriate staying do allow lots of big floaty stuff to be flown, lots of changes in tall head sails. This was apparent with the development of these sails and flying them from the relatively short foremasts on schooners. The shorter masts of luggers and gaffs would be a disadvantage.
    Ben Fuller
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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    At a guess the Fastnet and Hobart are 33% upwind. That would indicate that the events that for years dominated the offshore racing world were far from upwind biased.
    The basic algebra of a time-rate-distance problem suggests the opposite to some degree, I think. Consider: that 33% of upwind sailing is when boats will be going their slowest, both in terms of absolute speed, and in terms of VMG. A boat whose upwind performance is weak relative to other boats will spend even MORE time moving at those slow rates, compounding the disadvantage. It's the time spent moving at a certain speed that matters most, not the distance.

    I think that's why so much is made of windward ability for racing boats. It makes sense--for racing. But my perception is that sailing overall--I'm thinking mainly of mainstream production designs--has been much more influenced by these concerns than is warranted for people who aren't interested in racing. I think if sailors understood this better, there'd be much more interest in non-Marconi rigs.

    But hey, maybe most people just really want to be faster than the boat sailing next to them. Makes me glad I do most of my sailing alone, with no other boats in sight! My little unstayed lugsail rig is FAR cheaper and simpler to operate, which (I admit) gives me an inordinate degree of satisfaction that is worth giving up a bit of upwind performance.

    A sprit rig shares many of those virtues, though I don't like the fussiness of reefing, nor dealing with the long spar required.

    Tom
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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    But many of the great offshore races aren't around Olympic courses. The Bermuda, Transpac, round the world and many other offshore races are mainly about reaching or running, and still bermudan rigs perform better. At a guess the Fastnet and Hobart are 33% upwind. That would indicate that the events that for years dominated the offshore racing world were far from upwind biased.

    Is there any evidence that in real life the lug or gaff are actually significantly faster on the reaches, or fast enough to be able to do without spinnakers or reachers?
    If you were designing a boat for maximum performance for minimum effort, wouldn't you compare them under working sail? One of the things that bothered me about offshore racing was the need for a forepeak full of sails, and manpower to be constantly changing sails. I think it was Roger Taylor who put a 6 Meter rig on his Buzzard's Bay 25, only to find that one with the original gaff rig kept up just fine when they were racing, but with a lot less work.

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    Default Re: efficiency of the sprit rig

    WI-Tom, the Hobart and Fastnet stand out because they have a higher proportion of upwind than the Transpac, Bermuda, etc. The round the world races are said to be only 10% upwind - and yet the ketches were dumped because bermudan sloop rig was faster, even in Open 60s where sail area was not measured.

    There have also been many famously successful ocean racers that were not at their best to windward. Boats like the Farr designs and even many of the current IRC boats are at their best downwind and yet they win. If upwind performance was overly emphasised by the classic ocean races, boats that were inferior upwind would not have won - yet boats like Ragtime, Merlin, the Farrs etc had tremendous records despite being inferior upwind.
    Last edited by Chris249; 11-11-2017 at 08:13 PM.

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    Default Re: efficiency of the sprit rig

    And back in the day, seems to me that luggers and gaffers carried topsails, sometimes double tops. Sometimes combined with square tops. Baltimore clippers had courses that ran from the lower topsail yard to spreaders on the deck. Staysails, watersails, ringtails. Inner and outer jibs, flying jibs. Square riggers with royals, skysails, moonsails and stunsails.

    The only real way to measure efficiency is measure sail area strictly but put no limits on sail and rig shape. The purest manifestation of this is seen in the wings of class C catamarans: anything goes but you only get 300 sq ft and everything is measured. The evolved rig is 3 element stacked 3 high. Camber, twist and angle of attack completely controlled.
    Ben Fuller
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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    The Stars did see enough advantage from the 'short bermudan" rig so that when they were allowed in 1921, to quote Elder who was there"the good skippers, who did not start off with a Marconi, changed to it before 1921 was over".

    I'm not sure which of two rigs I'd go for. Sometimes I like rigs that require a bit more tweaking.
    Yes, they would have had less weight and windage aloft, as I said, but the racers still wanted a more efficient rig. The aspect ratio was the same, and the shape of the sail nearly the same, so I think that must have been the advantage.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    One would say there are hundreds of examples that indicate that your client is wrong. These examples are the racers of world's most popular lug-rigged racer, the (former) International 12 Foot Dinghy. They can get up to 180 or so (IIRC) boats to regattas, it's a major class in the Netherlands and Italy, and they have dipping lugs in which the mast is to windward.

    There's no logical way in which these hundreds of sailors, who race against each other week after week and therefore have innumerable chances to try each side (and have had for a century) could be wrong.
    Sunfish sailors think their boats are closer-winded with the sail against the mast. I wonder if this is also true with the balanced lug.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    One would say there are hundreds of examples that indicate that your client is wrong. These examples are the racers of world's most popular lug-rigged racer, the (former) International 12 Foot Dinghy. They can get up to 180 or so (IIRC) boats to regattas, it's a major class in the Netherlands and Italy, and they have dipping lugs in which the mast is to windward.

    There's no logical way in which these hundreds of sailors, who race against each other week after week and therefore have innumerable chances to try each side (and have had for a century) could be wrong.
    Chris, I know that almost everyone who knows about lugrigs is talking about a good and a bad side but I am asking if anyone else experienced this phenomenon. And I know the 12ft. Dinghy quite well, it has not a dipping-but a standing lugsail. I made one myself. Frank

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by johnw View Post
    If you were designing a boat for maximum performance for minimum effort, wouldn't you compare them under working sail? One of the things that bothered me about offshore racing was the need for a forepeak full of sails, and manpower to be constantly changing sails. I think it was Roger Taylor who put a 6 Meter rig on his Buzzard's Bay 25, only to find that one with the original gaff rig kept up just fine when they were racing, but with a lot less work.
    But has any one yet demonstrated any broad evidence to show that bermudan rigs are in fact slower under working sail? If Roger Taylor found that a bermudan was as fast then it was an outlier since we know that dozens of other classes tried both and almost all found the bermudan faster. Even some of the last dinghy high performane dinghies to make the switch (Renjolle, 16 ft Skiffs) have long since realised that the bermudan goes quicker.

    It's interesting to look at various handicaps that indicate bermudans are all that poor downwind. Typical allowances for not carrying a spinnaker under PHRF and yardsticks indicate an all-round speed loss of around 2.5-4%, which is not enormous. Compare that to the sort of allowances gaffers get under rating rules (as noted in earlier posts) or something like the allowance the Z Class Renjolle allow for gaff rigs - they get a 3% allowance over identical bermudan rigs, which seems fairly typical. So according to such allowances, the bermudan is normally without spinnaker is faster than the gaff with spinnaker. It's not conclusive, but it's interesting. While such handicaps are biased towards windward performance, for some of us that actually replicates our normal day cruising; where I've lived, for example, unless you beat to windward you wouldn't get to the good anchorages in the prevailing winds.

    Is the gaff less work, assuming one is comparing rigs that are otherwise as equal as can be? Is it easier to pull up an extra spar? Is the lower aspect with an extra stick up high actually more stable than a higher aspect sail with less ironmongery atop it? Is there any evidence that bermudan rigs need extra headsails? I haven't actually pulled my small headsails out for years, despite living in a windy corner of a windy area. If the wind gets too windy for full rig (which isn't until 20+ knots) then the boats truck on nicely under that tall, efficient mainsail alone.

    Obviously there are reasons for liking and preferring sprits, gaffs etc, and apart from everything else their lift/drag characteristics may well suit some boats better than bermudan. It's just that it seems very to find significant on-the-water evidence that they are as efficient in many ways as the bermudan rig on the normal hull.
    Last edited by Chris249; 11-11-2017 at 08:28 PM.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by FF View Post
    Chris, I know that almost everyone who knows about lugrigs is talking about a good and a bad side but I am asking if anyone else experienced this phenomenon. And I know the 12ft. Dinghy quite well, it has not a dipping-but a standing lugsail. I made one myself. Frank
    Sorry, I've only sailed an Italian version of the 12ft Dinghy and it seems that I mis-translated the Italian description of the rig. My apologies and I withdraw the comment.
    Last edited by Chris249; 11-11-2017 at 08:30 PM.

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    Default Re: efficiency of the sprit rig

    Quote Originally Posted by Chris249 View Post
    But no one has yet demonstrated any evidence to show that bermudan rigs are in fact slower under working sail. If Roger Taylor found that a bermudan was as fast then it was an outlier. We know that was not the case in 6 Metres, 12 Metres, Stars, H, Z or J Class Renjollen, Mullet Boats, 18, 16, 14 and 12 Foot Skiffs, International Canoes, Zeddies, Xs, Ys, Ts or any other of the alphabet soup of NZ classes, the Raters, or just about any of the dozens of classes that tried both and found the bermudan faster. Even the Mirror and Heron classes, small slow family dinghies, have recently dumped the gunter and gone no slower.

    It's extremely difficult to believe that Taylor was right and the various legendary sailors and designers involved in shifting all those classes from gaff to bermudan all got it wrong. It's also noticeable that some of them (such as Uffa Fox) were very willing to admit that for certain types, the gaff or gunter was faster even when other boats had switched to bermudan. That seems to indicate that they were not biased; in Uffa's case he just recognised that in the technology of the day, big-rig dinghies like 16s and J-Jolle had to reef often and that meant that it was faster to reduce the effective height of the spars. In most other classes, bermudan was faster. Similarly, in 12 Sq M Sharpies the bermudan and gaff were used alongside each other for a long time until the superior stability of gaff when the boats were moored led to it becoming mandatory.

    There is no evidence of bias or blindness and therefore surely we just accept that the many thousands of sailors, designers and sailmakers involved in the huge transition to bermudan did so for good reasons. There may be occasional classes where the gaff is no slower for various reasons, of course.

    Nor does the available evidence from on the water indicate that bermudans are as poor downwind as often claimed. Typical allowances for not carrying a spinnaker under PHRF indicate a speed loss of around 2.5%, which is not enormous. That seems pretty typical of the sort of allowance one gets across various systems, including yardsticks from other countries. Compare that to the sort of allowances gaffers get under rating rules (as noted in earlier posts) or something like the allowance the Z Class Renjolle allow for gaff rigs - they get a 3% allowance over identical bermudan rigs, which seems fairly typical. So according to such allowances, the bermudan without spinnaker is faster than the gaff with spinnaker.

    I still haven't seen any evidence that the gaff is less work. Why is it easier to pull up an extra spar? Is the lower aspect with an extra stick up high actually more stable than a higher aspect sail with less ironmongery atop it? Nor is there any evidence that a bermudan rig has to have more headsails. I know that all of my bermudan rigs will go to 25 knots under full sail, depowering by mast bend and sail trim . Despite living in a windy corner in a windy part of the world, I haven't changed down to a small jib in several years; as the wind increases I just depower under the main and 105%, then drop the headsail, then go for a reef (which incidentally takes as little as 55 seconds, even single-handed even with a 47ft luff).

    Obviously there are reasons for liking and preferring sprits, gaffs etc, and apart from everything else their lift/drag characteristics may well suit some boats better than bermudan. It's just that it seems very to find significant on-the-water evidence that they are as efficient in many ways as the bermudan rig on the normal hull.
    I've not said the gaff rig is less work than the Bermudian, although Taylor indicated that in that particular race it was. I think fractional rigs, especially in small boats, are less work than masthead rigs because they depower better. This thread is actually about the sprit rig, or was before it started drifting.

    When I started racing, we used up to 170% overlap, and had to change the jib often on our masthead rigs. Under IOR, 150% overlap became common, and spinnakers became more specialized. Are cruiser-racers now using 105% in light air these days, or do you not have light air?

    In small boats kept on a trailer, I've developed a preference for unstayed rigs, which go together much quicker than stayed rigs. The problem with the Bermudian rig in that case is, if you don't have a jib, the mast gets tall pretty quickly as the rig grows. With my bad back, even stepping a 20' stayed aluminum mast is a challenge, never mind hooking up everything and still having time to sail. So, I'm wondering, if I build a small boat with a sprit rig, would I have anything like comparable performance to a Bermudian sloop with no spinnaker? If the efficiency loss is 3%, maybe the tradeoff is worth while. If it's 10%, maybe not.

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    Default Re: efficiency of the sprit rig

    Here's an example. I designed this for a 135 square foot sloop rig. Here's the hull wearing a 150 sq. ft. sprit rig. I'm wondering, will I really be able to carry more sail with the low-aspect rig, and will the extra area make up for the loss in efficiency?

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