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EarthBM

Why do multis (supposedly) not point as high?

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Not starting any tribal wars here, just a simple boat design question.

 

Is this because of leeway? So with effective foils this goes away?

 

Is this because of the geometry where the lateral resistance (from the leeward hull) is leeward of the center line? Why would this matter with balanced helm? (This reason would explain tris pointing better than cats)

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That's pretty much an urban sailors myth IF you're talking well designed high performance multi vs well designed high performance mono hull. C Class and other performance cat's point very high- at least equal to a mono. In some conditions, speed made good(vmg) upwind is enhanced by footing off a bit in a cat.

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Often the answer is that they choose not to point as high (wrt the true wind) because it's faster not to. I think you may be confusing "getting upwind" with "sailing close to the true wind".

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Glowboat, our F24 tri can point as high as most any boat, but the VMG is not as high, so it is often better to bear off a few degrees.

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Hi. It is not an urban myth but a reflection of history with older boats that did not have good could for upwind work. On my A cat I can sail over a Melges 24 by out pointing but it is faster to sail roughly the same angle as the Melges and be double their speed. No problem to match upwind angles of any dinghy or keelboat that has been I the same course as me. Other modern multis may not be quite as close winded but can still preform well. Peter Johnstone wrote a nice article on heavy weather tactics that discuss this question too.

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Simple answer; they're sailing faster than any mono to windward ... therefore multihull apparent wind is carried further forward.

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I think that is pretty much a myth based on old designs or big, heavy cruising cats (without boards). I can't speak for high performance cats, but on the more modern F-25/F-27/F-24's I've sailed we've never had a problem with pointing with the monos if we choose.

 

The other myth you'll here a lot, is that multis don't do well in light conditions. Complete B.S. Most multis have much, much higher SA/D ratios than monos of the same length and much narrower hulls.

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Agree with all this for modern multis, but thing that makes us look low pointing often is that if we are on same smaller cans course and go around a bottom mark close behind one (they start 10 mins ahead at my club so we can have fun), our width (and clear vision if you are driving from the happy hull) makes it difficult to roll them from windward side. If you are successful they are not happy, and in club racing it is not polite for most of us to lose friends like this. Easy way is foot off and come back up until you find another one. Their understandable perception is that they have outpointed you.

 

Peter H

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I think that is pretty much a myth based on old designs or big, heavy cruising cats (without boards). I can't speak for high performance cats, but on the more modern F-25/F-27/F-24's I've sailed we've never had a problem with pointing with the monos if we choose.

 

The other myth you'll here a lot, is that multis don't do well in light conditions. Complete B.S. Most multis have much, much higher SA/D ratios than monos of the same length and much narrower hulls.

There is a bit of a divergence in multi design, on the one hand there are lots of designers making lovely boats with boards that point well and keep moving in the light. Then there are companies like fountaine pajot building floating condos that reinforce the old ideas that multihulls stop in light air, tack through 120 degrees, won't sail in above 15 knots etc. Not really a myth, just an overgeneralisation from people who very rarely see a well sailed racing multi

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it was true when the multi in question was something like a hobie14.

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Back the bus up a bit. EarthBM what type of Multi's are you talking about? Sure C-Class or racing multis point well but is that the question?

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Simple answer; they're sailing faster than any mono to windward ... therefore multihull apparent wind is carried further forward.

^^ that is under appreciated by most sailors. I'm sure this will stir up some s**t:

 

Any sailboat's most efficient pointing angle (relative wind angle) is the sum of the aerodynamic and hydrodynamic drag angles (arctan(L/D ratios)). This by itself isn't a revelation or even controversial, it is simply a mathematical consequence of the definition of the terms. However the L/D ratios are inherent (mostly) in the design of the boat - efficiency of the rig minus the windage of hulls, efficiency of the foils, etc. - so its most efficient pointing angle is built into the design. It varies very little over normal wind strengths. As a boat picks up speed, the apparent wind pulls ahead, to maintain the more or less fixed efficient pointing angle the true wind angle gets wider. The increase in speed must be enough to overcome the extra distance sailed.

 

Everyone knows this so far. If you go on to plot the resulting VMG as a function of boat speed, with a fixed true wind and fixed apparent wind angle, you will notice that for a given set of numbers, there is a maximum VMG that can be achieved. Boat speeds above that will result in the distance sailed increasing faster than the boat speed, and VMG will fall. Due to the nature of cosines, a more weatherly boat suffers much less than a weatherly boat. So an A class cat, with very efficient rig and foils, can sail very fast and still do good VMG because its pointing angle is fine. On the other hand typical cruising cats, with a lot of windage in the hull and superstructure and maybe not too efficient underneath either, cannot do well to windward no matter how fast it sails because its pointing angle is modest.

 

Here are some examples. The first is a boat with an efficient pointing angle of 28 degrees (not bad for a cruising boat) in 10 knots true wind. Its maximum VMG is 5.6 knots at 11 knots boat speed and 18.3 knots apparent. Go faster than that, and VMG drops:

 

Apparentwind2810_zpsee1509ba.jpg

 

If the pointing angle is widened to 35 degrees (more typical of a cruising cat) in the same 10 knot wind the maximum possible VMG is 3.7 knots at 8 knots boat speed and 15.4 knots apparent. Go faster, and again VMG drops:

 

Apparentwind3510_zpsd98ec242.jpg

 

Cracking off of the most efficient pointing angle only makes things worse. Obviously in lots of wind the situation improves, because boat speed is smaller relative to wind speed and the apparent wind angle changes less. And as efficient pointing angles get into the teens (as they do in extreme racing boats) there is less effect even at lower wind speeds. But it is a problem for cruising cats. Cruising monos tend to have a little better pointing angle and aren't able to go very fast, so less of an issue. Note that a boat pointing at 28 degrees only needs to do less that 5 knots to beat the 35 degree boat's best possible VMG.

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small tight tacking course handicap racing mixed dinghies on an old beachcat with big daggers

 

starting well behind, the cat could outpoint most of the poorly sailed monos with old sails

 

but could never shoot up the inside of a well sailed laser with flat sails

 

easy enough to round the outside of them

 

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Thanks. Wonder if the answers would be the same on a monohull forum. Was just going on general comments I've heard over years (eg from a guy with an Outremer 49) and my memories from learning to sail on a Hobie 16.

 

Some examples (A-cat, Laser) point higher because they don't have a foresail, I think.

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Ok so you where asking about small racing boats rather than the average cruiser / racer multi.

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sailing behind a "normal" mono - no moving keel - in a gust with a daggerboard multi shows the mono heeling a lot in the gust - then pointing higher- but don't go faster - but drifting downwards - the multi point higher and accelerates...

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being the most produced multi

 

the dagger-less hobie 14 + 16 are probably more responsible for the the bad reputation multis have than anything else

 

by skilled hobie sailors they can be tuned and sailed reasonably high

 

but the mono sailor can only get them to reach fast, which is what they were designed to do

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big cat cruisers like lagoons

 

aren't made for pointing either

 

which is why they have 2 engines :D

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The bad pointing reputation began back in the earliest modern development multihull days and the Pivers with their too small float fins were probably the main culprits; the other point that started derogatory commentary was that they could reach much faster and pass monos of the times - and that didn't enamour them either. Also any overloaded and overbuilt multi was and is hopeless to windward.

But the smaller and near half Century old Piver designs like the Nugget can be transformed with the fitting of a decent basic daggerboard ... and then they'll point as high as any other boat. And reaching performance remains as before; this one has held 19 knots, not bad for a 40 year old boat.

post-100779-0-19345900-1407904870_thumb.jpg

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Actually, it's a combination of all of the above. In the early days, the sailmakers were cutting the sails too full. So, the combination of higher speeds and too full sails were a big contributor. The designers of performance multihulls who included daggerboards or centerboards thought that the higher speeds meant that the foils should be smaller (like a supersonic jet wing); so the boats didn't have enough lateral resistance. After racing a 30' cat of my design in the open ocean I came to realize that for multihulls to go faster upwind in big waves, footing more wasn't the solution. We found ourselves launching off waves with enough velocity to break the boat if we kept it up. At that point both my daggerboards and rudders got bigger and significantly deeper; and my rigs became higher aspect ratio. A uni-rig like an A cat points higher than a boat with a jib, and a boat with a Solent style jib points higher than a boat with a genoa. So, not only did the mainsail get taller and narrower, the genoas turned into Solent jibs. The next boat, a 35 footer, could climb higher than equivalent size monohulls, but it was (and is) still faster to foot off. The pointing gap has been significantly narrowed in the last 20 years, but the monos are still pointing a bit higher...and getting to the weather mark slower.

 

Of course, if you watch a high speed monohull, like a Volvo or IMOCA boat, they don't point well either...

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You've raced Deuce Coupe in many races over the years and probably in a lot of mixed mono/multi fleets.

 

What mono boats are you equeal with to the weathermark?

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You've raced Deuce Coupe in many races over the years and probably in a lot of mixed mono/multi fleets.

 

What mono boats are you equeal with to the weathermark?

That's a good question. Wind velocity has a lot to do with it. In light air the extra wetted surface of a cat makes us a little sticky. Conversely, in heavier air the boat seems to break free and find another gear. But I will tell you this - pointing ain't a problem with that boat, and Merlin is even better. The only monohull in the Tampa Bay area that I can think of that has taken us upwind is Doug Fisher's Excess. That said, there are very few really good bigger monohulls in the Tampa Bay area anymore to pace against. Typically, they start us first, we disappear, and then help the monos tie up at the dock later. Occasionally in really light air a couple of them will sail up to us. I suspect the newer more high tech monohulls sailing in other parts of the country would kick our ass...but then, Deuce Coupe is 30 years old.

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The apparent wind angle upwind for Dogzila as 12 degrees, 17 degrees downwind.

Mono's are less efficient upwind, and therefore gain more by going as high possible, while a good racing multi are more efficient in converting the wind power into forward speed, will generally sail with the same apparent wind angle, but further off the wind, resulting in better overall speed to windward.

 

Just as there are multi that don't sail to windward, there are also plenty of cruising monohull's who can't sail to windward either.

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f course, if you watch a high speed monohull, like a Volvo or IMOCA boat, they don't point well either...

 

Is that actually true?

 

Whilst they may not sail as close to the wind as a circuit racer like a TP52 the ocean racers you have mentioned have canting keels and asymmetric dagger boards. The way they seem to sail is with their sheets a little eased and a few degrees lower, but because of the foil design they have little to no leeway.

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Velocity headers.

 

Some (the ubiquitous pluralism) (the ubiquitous minority?) call them velocity lifts, but Jesus Fucking Christ...

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With the fat cruising cats, it's an ugly combination of windage drag and hopeless shallow foils. I've seen Lagoon VPPs that suggest 60 TWA is the best they can do. Almost square rigger territory.

 

Our relatively light 40' cruising cat with daggerboards outpoints the typical 'average' cruising monos in light - med winds but when the wind gets up our increasing windage really hurts us.

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^^^ Most cruising cats are underpowered most of the time (maybe all the time with careful owners). Typically they're going to find their upwind VMG at pretty broad apparent wind angles because there isn't enough power in their rigs. Efficiency (eg lift:drag) plays into it but I think it's secondary to lift for the "typical" cruising cat. Adding more sail power adds cost and risk beyond what is ideal for the service.

 

FWIW, my experience on my 40ish foot cruising cat with good foils is that my upwind vmg v monohulls improves as the wind gets up as long as I'm willing to sail nearer and nearer the edge of stability. The thing is, sailing like that isn't safe or relaxing.

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If you were simply (!!!) trying to avoid a pitchpole why wouldn't you just smoke both sails?

 

In a more controlled situation I get having some front to back order.

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Not starting any tribal wars here, just a simple boat design question.

 

Is this because of leeway? So with effective foils this goes away?

 

Is this because of the geometry where the lateral resistance (from the leeward hull) is leeward of the center line? Why would this matter with balanced helm? (This reason would explain tris pointing better than cats)

There is a world of difference between where you point your boat and where it goes. I can point my cat 5 degrees off the true wind but it won't go there.

The question is: "Why do multis (supposedly) not point as high?" The answer is: because multihull skippers are more skillful!

A better question would be Why do multis not have as good a CMG to windward? and the answer: They don't.

I remember sailing offshore on XL2 in a SSAA race competing with a 40' ocean racing keelboat of similar vintage. The keeler started 5 mins ahead of us and we were both sailing south from Sydney Harbour in a fresh south-easter. We were behind and to leeward, sailing faster (of course). The keeler was pointing 10 degrees higher than XL2. While pointing lower we sailed from behind and to leeward to beside and to windward to ahead and well to windward. The keeler was pointing higher but making much more leeway, Resulting in much worse CMG to windward. I don't know if he could have improved his CMG by pointing lower. I do know that if I pointed where he pointed I would have made more leeway than he did. So perhaps multihulls just make it clearer where you have to point the boat.

In addition, since owning Two Tribes I have found that getting the windward hull clear of the water gives me another 10 degrees approx' CMG to windward.

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I do know that if I pointed where he pointed I would have made more leeway than he did. So perhaps multihulls just make it clearer where you have to point the boat.

In addition, since owning Two Tribes I have found that getting the windward hull clear of the water gives me another 10 degrees approx' CMG to windward.

 

XL2 is a sleek daggerboard cat - how can it get a lot leeway in a breeze if its up to speed (not point as high as it goes slow) - the daggerboard are very efficient in 10knots - and is around 90 degrees (if they is good) - ok the VMG would maybe be lower - but why should it get more leeway than the heeled mono?

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just to throw a spanner in the works.... tacking time. big cruser cats no issue but smaller dinghy cats on smaller courses are a big issue. i always teach my students (small lake, newcat 14s, middle, heavy winds, close reach tack once or twice, dont get into a tacking battle with a monohull. you will lose. i can tack a 420 in about 6 seconds and lose very little boat speed. a cat can't tack as fast. fundamentally its like a car with no diffs. the leaward hull has to travel further than the windward. so i guess what I'm saying is pointing angle is not the issue. speed to next mark vs pointing angle plus time lost in each tack is. so a monohull will tack on a gust that heads up for a while because he loses less time makes for the mark, a cat should ignore these minor shifts not because it can or can not point as high but because it id do much faster on a close reach than a mono on a close haul. a mono if over powered on close haul can pinch ( depower by luffing slightly ) but for a cat ( typically heavier foot for foot) that isn't a good thing.

 

hope that makes some sense . had a few glasses of wine after a good day blasting around our lake in an f4 gusting f6 . oh such fun :)

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Not starting any tribal wars here, just a simple boat design question.

 

Is this because of leeway? So with effective foils this goes away?

 

Is this because of the geometry where the lateral resistance (from the leeward hull) is leeward of the center line? Why would this matter with balanced helm? (This reason would explain tris pointing better than cats)

 

The question is: "Why do multis (supposedly) not point as high?" The answer is: because multihull skippers are more skillful!

 

It's no wonder that some people complain of an anti-multi bias, when some multihullers put themselves on a pedestal and show such anti-mono bias.

 

The best multi sailors are brilliant, but if multihull sailors are so much more skilful as a breed then why do they not dominate the monohull sailors when the two meet? For example, the last time the multis were in the Olympics, the winning skipper was a guy who was not fully competitive even at national level in his Laser career. The third-placed skipper was another guy who was not as successful in his long Laser career as in cats.

 

Yes, multis often have best VMG at lower angles, but that does not mean that their skippers are more skillful; it's physics and boat design. Multis are great boats that breed great sailors, but multihullers telling everyone how much better multi sailors are is not a good look (to put it mildly).

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Several reasons.

Average racing mono is powered up in 10knots so he can point higher. (before a mono is powered up it has to foot as well.) Average multi is probably not powered up till 15 knots.

Very few multis have enough dagger board to prevent leeway. Some of the new Zealand boats have dealt with this by using large asymmetric boards. 888 for example has asymmetric boards about 4m long.

On my cruising 40" multi in under 12 knots short tacking any racing mono will smash us to windward. 12 to 20kn same as 40' racing mono. Open water in 20 kn about the same as a cookson 50 (canting keel carbon race boat) However we never point as high.

I know this because we passed them at Airlie (both down and up wind)

Tacking time and speed loss is huge on an average multi.

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Supplementary question from the sideline.

And don't trimarans tack and go to weather better than catamarans ?

(Assuming similar design/foil development)

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coupla ideas from real life. Short waterlined, lightweight multis are expected to pace long, optimized monos to weather. Especially in light air and chop this is very difficult. The monomen look at your rating and assume you should be able to go to weather with a fast 50 footer. They have tall mast, deep keel, lots of waterline, big sails. If you want to see a little, lightweight multi pounding some fast monos in the ocean check out the crazy youtube thread posted by the obviously mental mundt.

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It's no wonder that some people complain of an anti-multi bias,

 

A strawman says what?

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You are getting answers to two different questions.

One has do do with perceived deficiencies of cats in the past and how to improve them. But the other question is simply a matter of aero-hydrodynamics.

Take a cat with a displacement and length equal to a monohull. The cat has 3 times the sail carrying power. The wavemaking resistance is reduced compared to the monohull because the bow wave is less (narrower waterline) and with the hull flying there is less wetted area too. So the cat's change in speed for increase in power is greater than the mono.

 

Now take an even more typical way of looking at ti. Take a cat and a mono with the same length and same sail area. The mono is a keelboat. To carry that sail, it is heavy. It has a "displacement" hull and wide entrance angle. So it makes bow waves but also big transverse waves. It's resistance goes up with the 4th power rather than simply squared for the cat. So trying to get to the weather mark by going faster, for the mono, won't work, because it isn't going to gain speed. The cat will.

To understand this, look at iceboat polars. They don't have any resistance at all, other than the air resistance. They go to windward fastest at ~50 degrees off the wind.

 

A better way to frame the question is, "why do monohulls try to go to weather by going so slow? Answer: Because they can't go any faster, might a well point toward the wind as close as they can.

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Curious and honest question.

 

Anybody know the tacking and gybing angles for the America's Cup cats last time around... or the Little America's Cup C class cats?

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When someone says "multi hull" keep in mind that includes tris and cats. Many people who have not sailed multis just assume tris and cats have the same sailing characteristics, which we all know is completely false.

 

Some one above mentioned they would not get into a tacking dual with a mono. It has been my experience that I have no problem on my F-24II sword fighting upwind with boats of similar length. And that should not be surprising because most tris (not speaking for cats) have very narrow waterlines and very high SA/D ratios combined with a generous amount of rocker. They turn quickly and accelerate out of the tack quickly.

 

Not to derail the thread, but the other multimyth is that they don't do well in light air. Narrow waterlines and lots of power make great light air boats IMO.

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"Multihull" as being used in this thread is covering an astounding variety of boats. There are multihulls that go to weather like a scared witch. There are multihulls that practically speaking will not go upwind at all. There is variety in monohulls as well, but I would say not the same range.

 

So when you say "multihull" you really need to be more specific.

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Simple answer; they're sailing faster than any mono to windward ... therefore multihull apparent wind is carried further forward.

 

Bingo. You'll see the same issue with any high speed boat (moths, etc).

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Simple answer; they're sailing faster than any mono to windward ... therefore multihull apparent wind is carried further forward.

 

Bingo. You'll see the same issue with any high speed boat (moths, etc).

 

or iceboat or sailcart.

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Simple answer; they're sailing faster than any mono to windward ... therefore multihull apparent wind is carried further forward.

Bingo. You'll see the same issue with any high speed boat (moths, etc).

or iceboat or sailcart.

Yep. +1000 for the Marx Brother. Relative speed to wind, pure and simple. Vector addition 101. And further limited by rig geometry and type.

 

Conventional soft sails on a monohull racing yacht will achieve high teen AWA, upwind, and achievable TWA or "height" is as always a function of AWA and boat speed relative to wind speed. A similar rig on a racing multi, moth or iceboat will also achieve a similar high teen AWA (maybe slightly less as the sails are cut flatter) but as the boat is moving so much faster relative to wind speed the achievable TWA is fatter, and hence they point lower than even a high tech racing mono - albeit at a higher VMG more often than not.

 

Take the jib away and a soft sail rig can go a few degrees higher as the jib is sheeted off the centreline which limits its angle of attack. Note how tight TP52s and other hot race boats sheet jibs these days to get a sense of that limiting factor. Note also how small the AC72 jibs were - used for steering through tacks as much as anything else.

 

The precise reason C and A Cats, land and iceboats and other high speed boats including foiling monos such as Moths choose una rigs, and where practical and class-legal, solid wing sails, is a combination of that jib sheeting angle limitation, plus the reality that a solid wing has a superior lift/drag ratio than a soft sail - meaning that can achieve a higher AWA than soft sails for a stability-limited amount of drive, in turn allowing a smaller achievable TWA. So solid wings can always point higher in these boats.

 

Solid wings have been tried in Moths with marginal results - the weight penalty at small scale, limited practicality and inherent fragility so far outweigh the aerodynamic benefits, but for an inherently stable multi platform it's a different story.

 

Fat-assed cruising monos don't achieve anywhere near the high boat speeds relative to wind speed that racing cats can, have soft sails, and can also often have relatively crude rig geometries that are compromised by cruising amenity based on the notion that most of their sailing is reaching or downwind. If they really need to get upwind in a hurry, they drop the sails and start the donk. Add up those factors and they often don't point to well upwind relative to the average mono.

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High teen AWA? Really? What were AC AWAs?

 

Does a rotating teardrop shaped mast make you point higher? Or since the forward edge of the traditional non rotating round mast fk'es up the mainsail shape anyway it can be sheeted tighter?

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The lift-drag ratio of the wing is higher than the soft sail on a conventional mast. That doesn't mean that your optimum VMG will be at a higher angle. It just means that you produce more lift for a given amount of drag and along with that, a tighter apparent wind angle at whatever true wind angle you are sailing.

 

It is worth realizing that it isn't a simple swap, "gee, this rig points 5 degrees higher so I'm now going to sail 5 degrees higher." Instead, you may be pointing the same or some intermediate angle and going rather faster. The more sleek the hull system, the more these aerodynamcal considerations come into play. As I said above, a heavier or more displacementy hull will force you to point toward the wind to get there--provided of course you have adequare lateral plane to do that at a lower speed. (This is where all that muddle about daggerboards comes into play).

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When I sailed a Toro34 (34ft sport cat) last winter in the Caribbeans, we were tacking at 90 degrees, or maybe few degrees less but we were not trying to achieve something about that. But I remember when I sailed the Toro on the St-Lawrence river, going up the current, a 1.5 to 2 kt current, and with the wind coming from the exactly same direction than the current, we were pointing far better than the monos. In the current they were highly penalised by their low speed.

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This MOD70 polar shows best VMG TWA of 45 degrees, giving it 22.5kt SOW in 30kt TWS. Unless my trigonometry failed me again, this is 26 degrees AWA,

MOD70a.JPG

 

This TP52 polar has TWA of 35, 10kt SOW in 30kt TWS. The same trigonometry gives me the same 26 degrees AWA!

TP52POLAR.png

 

So G. Marx is spot on.

 

The question was more about the boats people actually use, Outrermers and such.

 

This thread made the world famous Pg 1 http://sailinganarchy.com/2014/09/03/a-pointed-question/

With this kind of fame, I know that money, women, friends are sure to follow. For the press inquiries "EarthBM" = "Earth Bound Misfit" from this Pink Floyd song:

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Fat crusing cats from the 60ies and 70ies surely didn't help busting the myth. I delivered such an ugly fat Bastard a few years ago. The tacking angle was ridiculous. This boat just didn't do 'upwind'. We managed something like 80 to 85° of true Wind angleangle.a real pro might have gotten that vital extra 5° out of her.

Don't pinch her, the owner had instructed us. She doesn't go if you pinch her!

Best joke I've every heard.

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The lift-drag ratio of the wing is higher than the soft sail on a conventional mast. That doesn't mean that your optimum VMG will be at a higher angle.

 

Yes it pretty much does. Look up "Lancaster's Theorem".

 

The question was more about the boats people actually use, Outrermers and such.

 

This is why I said multihulls come in many different colors and flavors. I have had no trouble passing production cruising cats to weather, even the Outremers and Catanas, in spite of a 10,500 lb lead handicap. I'm sure a Gunboat would be a different story, but in satellite tracked and published Caribbean racing venues, even the Gunboats are beaten upwind (though only slightly) by similarly sized and built monohulls. You cannot lie about it in these venues.

 

In pure racing boats, catamaran hydrodynamic L/Ds are better while rigs are rigs. The translation to a cruising boat though, changes that quite a lot.

 

DickD summarizes it pretty well in his post above.

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I'm really happy to say that myth has been finally totally busted. Modern day multis can point higher, but after they complete the roll they go back down for speed.

 

However, sailing on all sailboats is fun.

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This MOD70 polar shows best VMG TWA of 45 degrees, giving it 22.5kt SOW in 30kt TWS. Unless my trigonometry failed me again, this is 26 degrees AWA,

MOD70a.JPG

 

This TP52 polar has TWA of 35, 10kt SOW in 30kt TWS. The same trigonometry gives me the same 26 degrees AWA!

TP52POLAR.png

 

So G. Marx is spot on.

 

The question was more about the boats people actually use, Outrermers and such.

 

This thread made the world famous Pg 1 http://sailinganarchy.com/2014/09/03/a-pointed-question/

With this kind of fame, I know that money, women, friends are sure to follow. For the press inquiries "EarthBM" = "Earth Bound Misfit" from this Pink Floyd song:

26 AWA sounds low for a TP52 but in that wind strength they won't be sailing minimum angles as the water will be rough.

 

I've raced a 2005 vintage model Judel/Vrolijk 52 with well calibrated wind gear, we were getting 21 AWA upwind, though not at 30 knots TWS. I'd imagine more modern 52s with much tighter jib sheeting angles do a few degrees better, at least in flat water. Rough water they'll deliberately foot a bit.

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High teen AWA? Really? What were AC AWAs?

 

Does a rotating teardrop shaped mast make you point higher? Or since the forward edge of the traditional non rotating round mast fk'es up the mainsail shape anyway it can be sheeted tighter?

IACC boats were getting around 19 AWA as I understand it. They were about the most efficient displacement hulled monos ever known upwind - slim, heavy, massive ballast ratios, big and very stiff rigs, massive forestay tensions, super flat sails. Rotating wing masts could have made them even more efficient but weren't allowed in their rule and the engineering challenges would have been interesting. I understand their mast jack loads were up around 60 tons

 

A rotating teardrop allows the main to work more effectively at tighter angles as the flow on the leeward side is less disturbed by the mast, basically increasing the lift/drag ratio of the main.

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Still confusing 'pointing' with CMG. Point your boat anywhere you like. Dont expect it to go where you point it.

I can sail up behind an Etchel and point my cat where the Etchel is pointing and go where the Etchel is going.

Or I can point my cat 'lower' and go 'higher'. If I sail efficiently I 'point' lower than the Etchel but I sail higher.

That's why efficiently sailed multihulls don't 'point' as high. They get better CMG to windward by 'pointing lower'.

 

Then there is VMG to windward to consider.

Velocity, not speed. By 'pointing' lower a multihull can achieve more speed and that combined with the better CMG to windward gives much better VMG to windward.

 

Then there is 'hull flying'. When a cat flys the windward hull or a tri flys the the centre hull there is a significant improvement in speed and in CMG to windward.

That's why we pull away ('point lower') to get a hull out.

Multihulls 'point' lower to sail higher.

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Still confusing 'pointing' with CMG. Point your boat anywhere you like. Dont expect it to go where you point it.

I can sail up behind an Etchel and point my cat where the Etchel is pointing and go where the Etchel is going.

Or I can point my cat 'lower' and go 'higher'. If I sail efficiently I 'point' lower than the Etchel but I sail higher.

That's why efficiently sailed multihulls don't 'point' as high. They get better CMG to windward by 'pointing lower'.

 

Then there is VMG to windward to consider.

Velocity, not speed. By 'pointing' lower a multihull can achieve more speed and that combined with the better CMG to windward gives much better VMG to windward.

 

Then there is 'hull flying'. When a cat flys the windward hull or a tri flys the the centre hull there is a significant improvement in speed and in CMG to windward.

That's why we pull away ('point lower') to get a hull out.

Multihulls 'point' lower to sail higher.

 

period.

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Interestingly enough, I just watched a Mod70 follow a fleet of sport boats around a common bottom mark. Of course the big tri was immensely faster - but surprisingly more weatherly too.

 

The Mod70 passed all the sport boats to weather - not to leeward.

 

I wonder if the answer isn't related to something a poster said above: CMG.

 

The Mod70 has enormous foils and was flying two hulls. The sport boats may simply make more leeway. So perhaps they can point as high, but their CMG is worse.

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Interestingly enough, I just watched a Mod70 follow a fleet of sport boats around a common bottom mark. Of course the big tri was immensely faster - but surprisingly more weatherly too.

 

The Mod70 passed all the sport boats to weather - not to leeward.

 

I wonder if the answer isn't related to something a poster said above: CMG.

 

The Mod70 has enormous foils and was flying two hulls. The sport boats may simply make more leeway. So perhaps they can point as high, but their CMG is worse.

They may have been pinching just to stay clear. Once clear they may have freed up 5 degrees and gone even faster. Remember that the higher the wind speed, the higher all boats will point (in general--excepting certain classes that are starting itno planing mode), A mod 70 at 6 knots of wind is probably pointing wider than 50 degrees. At 40 knots probably more like 40 or 45. Except for sea state issues of course. An IOR monohull would point 40-45 at 6 knots, and ~35 at 35.

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Yep, same with a Tornado vs keel boats. Groucho is right, multi go faster and have apparent wind more from the front.

Still, I would like to know the AC72 AWA vs a classic 12m AC.

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The 12 I've sailed on a lot generally operated on 20-22 degrees AWA upwind. 1987 boat with 3dl Kevlar sails

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Interestingly enough, I just watched a Mod70 follow a fleet of sport boats around a common bottom mark. Of course the big tri was immensely faster - but surprisingly more weatherly too.

 

The Mod70 passed all the sport boats to weather - not to leeward.

 

I wonder if the answer isn't related to something a poster said above: CMG.

 

The Mod70 has enormous foils and was flying two hulls. The sport boats may simply make more leeway. So perhaps they can point as high, but their CMG is worse.

They may have been pinching just to stay clear. Once clear they may have freed up 5 degrees and gone even faster. Remember that the higher the wind speed, the higher all boats will point (in general--excepting certain classes that are starting itno planing mode), A mod 70 at 6 knots of wind is probably pointing wider than 50 degrees. At 40 knots probably more like 40 or 45. Except for sea state issues of course. An IOR monohull would point 40-45 at 6 knots, and ~35 at 35.
the sport boat fleet was strung out for about a mile upwind of the mark before the Mod70 rounded. All boats on port tack for the duration of the "CMG test". It was pretty much a perfect test of CMG to weather.

 

And yes, the tri could have been pointing higher than max VMG just to make the lengthy pass - I could not observe that level of detail. But for sure it was not obviously pinching up.

 

Bottom line is that the tri chose to go over an entire fleet of mono sporties on the high side - after rounding exactly the same mark - and it looked pretty comfortable.

 

It would be interesting to hear from one of the little boats overtaken. The rig on that thing must have loomed overhead like a monster.

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Having been rolled to windward by a pair of J-class, and by a NY 50, I would have to say that "wind shadow" would come to mind.

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We own the only Pdq 36 that has had boards installed right from the get go .Built in 2003 with carbon boards ,5 feet more mast good kevlar sails and through a great deal of effort weighs in at 8000 lbs (no rig, engines in ) we used honey comb in the interior panels and a variety of other measures to keep the weight off.

 

It does not look stripped and has davits ,solar panels ,12vdc fridge and pressure hot water . this kept my wife on side and frankly is part of the fun.

 

Our first regatta in Yongestown NY 2003 against A fleet of 9 multihulls Including f28r f25c f27 and stiletto 23 we finished second .

I was very pleased .We started with a group of Beneteau 36.7s and some older IOR 1 tons . This was my first time with the boat against similar modern racer cruiser mono hulls .

Much to my (and theirs ) surprise we could sail over top of them with ease . Delphine was 5 minutes faster than the 36.7s (with good sails ) on a 1.25-1-5 mile beat .I know this because they had a start before us.

 

Modern cruising catamarans do point as high if they are designed to do so . There are sacrifices either in comfort or cost that must be understood . A 40 foot cat with a fly bridge is never going to go to weather in any meaningful way and no one should be surprised ,but it will be great at the dock Party

DAvid

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We own the only Pdq 36 that has had boards installed right from the get go .Built in 2003 with carbon boards ,5 feet more mast good kevlar sails and through a great deal of effort weighs in at 8000 lbs (no rig, engines in ) we used honey comb in the interior panels and a variety of other measures to keep the weight off.

 

It does not look stripped and has davits ,solar panels ,12vdc fridge and pressure hot water . this kept my wife on side and frankly is part of the fun.

 

Our first regatta in Yongestown NY 2003 against A fleet of 9 multihulls Including f28r f25c f27 and stiletto 23 we finished second .

I was very pleased .We started with a group of Beneteau 36.7s and some older IOR 1 tons . This was my first time with the boat against similar modern racer cruiser mono hulls .

Much to my (and theirs ) surprise we could sail over top of them with ease . Delphine was 5 minutes faster than the 36.7s (with good sails ) on a 1.25-1-5 mile beat .I know this because they had a start before us.

 

Modern cruising catamarans do point as high if they are designed to do so . There are sacrifices either in comfort or cost that must be understood . A 40 foot cat with a fly bridge is never going to go to weather in any meaningful way and no one should be surprised ,but it will be great at the dock Party

DAvid

Sure you sailed over the top of them with ease but were you pointing higher or were you pointing lower but making less leeway and thus sailing higher?

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That is a fair question we pointed about the same but because of the good daggerboards we seemed to make less leeway. Our boat speed was greater as well. Itwas a fair match as far as apples and oranges are concerned all boats having good laminate sails etc. I have sailed catamarans for 50 years starting on warhams and sailing on every early design known so I understand about not going upwind . As long as you compare similar design concepts in both types of boats I think you will find that cats can go up wind .Ichartered a shoal draft benateau 45 two years ago could not tack (vng) through 100

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In the Sail for Hope this year my 24' Corsair rolled over a new J88 with 3Dis to windward on the upwind leg. Similar PHRF numbers if I recall. I am 90.

 

That was a fun race, think I will add it to our yearly racing schedule.

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That is a fair question we pointed about the same but because of the good daggerboards we seemed to make less leeway. Our boat speed was greater as well. Itwas a fair match as far as apples and oranges are concerned all boats having good laminate sails etc. I have sailed catamarans for 50 years starting on warhams and sailing on every early design known so I understand about not going upwind . As long as you compare similar design concepts in both types of boats I think you will find that cats can go up wind .Ichartered a shoal draft benateau 45 two years ago could not tack (vng) through 100

You are right about comparing like with like. I only started with cats in 1981 and in those days Tornados and A Class were already making better CMG than equivalent monohull dinghys and skiffs. But bigger multis were using full sails that were appropriate for hullspeed limited boats.

These days I sail my 9m racing cat in a fleet where the top keelers are 11m ODs. They make good CMG but not as high as they point (they make a fair bit of leeway). I would not try to point where they point, I would make more leeway than them if I did that. But when I get it right I make better CMG by pointing lower and making negligible leeway. I go from directly behind to ahead and above. To get it right I have to concentrate on not pinching. Pinching results in slow and low. Try to pinch up to a mark and I definitely won't make it. Keep both sides flowing and the boards working and most times I will.

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^^^ Most cruising cats are underpowered most of the time (maybe all the time with careful owners). Typically they're going to find their upwind VMG at pretty broad apparent wind angles because there isn't enough power in their rigs. Efficiency (eg lift:drag) plays into it but I think it's secondary to lift for the "typical" cruising cat. Adding more sail power adds cost and risk beyond what is ideal for the service.

 

FWIW, my experience on my 40ish foot cruising cat with good foils is that my upwind vmg v monohulls improves as the wind gets up as long as I'm willing to sail nearer and nearer the edge of stability. The thing is, sailing like that isn't safe or relaxing.

This thread is confusing as some are speaking about beach cats and others cruising catamarans. I have one of the proverbial '80s vintage pocket cruising catamarans. A British built Catalac 8M. This boat doesn't have mini keels nor boards, instead it has a rather unique hull design that relies on boat speed to grip on a tack. I find that my boat speed is the largest factor when going to weather, with large waves close behind. In light winds I can't point for crap..but give me 20 ++ knots of wind and I'll point with any of you mono guys.

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^^^ Most cruising cats are underpowered most of the time (maybe all the time with careful owners). Typically they're going to find their upwind VMG at pretty broad apparent wind angles because there isn't enough power in their rigs. Efficiency (eg lift:drag) plays into it but I think it's secondary to lift for the "typical" cruising cat. Adding more sail power adds cost and risk beyond what is ideal for the service.

 

FWIW, my experience on my 40ish foot cruising cat with good foils is that my upwind vmg v monohulls improves as the wind gets up as long as I'm willing to sail nearer and nearer the edge of stability. The thing is, sailing like that isn't safe or relaxing.

This thread is confusing as some are speaking about beach cats and others cruising catamarans. I have one of the proverbial '80s vintage pocket cruising catamarans. A British built Catalac 8M. This boat doesn't have mini keels nor boards, instead it has a rather unique hull design that relies on boat speed to grip on a tack. I find that my boat speed is the largest factor when going to weather, with large waves close behind. In light winds I can't point for crap..but give me 20 ++ knots of wind and I'll point with any of you mono guys.

80's? i have magazines from the 60's with Catalacs advertised. Compare them to similar design age british bilge keelers and the Catalac is a rocket.

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We are always disproving the myths with the monohull guys on Lake Pontchartrain and on the gulf coast with our Corsair Sprint 750. We sailed the 100 mile Gulfport to Pensacola race in late June and started with the Spinnaker A boats that included a J-111, Beneteau 40.7, J-122, and the Carkeek 40 Decision (a 40' custom Grand Prix racing monohull). The first leg of the race was a 12 mile dead upwind beat and we sailed boat for boat with the J-111 in 5-9 knots of wind in smooth water (both in height and speed). We used a screacher/Code Zero as our headsail. The only boat that beat us to the weather mark was the 40' Carkeek. The remainder of the race was a 7 mile reach, and then an 80 mile downwind leg. The wind speed was 6-10 knots. We were 2nd boat to finish and beat the J-111 elapsed by about 10 minutes but finished only 50 minutes behind the Carkeek (after 15-16 hours of racing). They were shocked not only by our upwind performance but also by how well our boat sailed downwind. The J-111 was steered by the 2004 Tornado Olympic medalist. The Carkeek rated -42 PHRF, we rated 33, and the J-111 39. The J-111 corrected out on us by 12 seconds but we both crushed the Carkeek on corrected.

 

Last month, we raced a 26 mile steeplechase race on Lake Pontchartrain that used staggered starts based on your rating. The breeze was 13-18 knots with steep short spaced chop. In a 37 boat fleet, the only boat that started behind us was Decision. We won the race and were ahead of Decision by about 12 minutes at the finish. There were three Melges 24's racing and they started 22 minutes ahead of us. We caught the last one about a mile from the finish. It was interesting that downwind in 14-15 knots of breeze, we appeared to be faster and lower than the Melges 24's which I did not expect. We were doing 8-11 knots upwind with tacking angles around 95-98 degrees so we were "pointing" about 3-5 degrees lower than most of the fleet but with much higher VMG. In the bar afterwards, a couple of the Melges 24 guys were making the "point" about how they "pointed" higher than us. I tried to "point" out to them that at the higher speeds we sailed, we go a touch lower but they did not want to discuss VMG! From their "point" of view, as long as they "pointed" higher, their boats were sailing better upwind.

 

When we first started sailing our Sprint 750 on the lake in 2007, we were told we were not welcome to mix it up with the monohull boats in PHRF racing because our boat handled poorly and sailed different angles. Now that we've proven we can sail the same angles upwind, sail the same angles as any other sportboat downwind, and tack as fast or faster than any keelboat, their case to exclude us is significantly weaker but trust me most don't like having us on the course (when they do allow us to enter). We try to be cool about our boat's performance but it's fun to see our boat with three sailors on board match or exceed the bigger boats upwind performance in all conditions (where they have 8-12 sailors on board). We find it silly they cannot just accept us like any other boat (especially after we have proposed to them that we have a multi-rating for light and heavy air to keep it fair).

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When we first started sailing our Sprint 750 on the lake in 2007, we were told we were not welcome to mix it up with the monohull boats in PHRF racing because our boat handled poorly and sailed different angles. Now that we've proven we can sail the same angles upwind, sail the same angles as any other sportboat downwind, and tack as fast or faster than any keelboat, their case to exclude us is significantly weaker but trust me most don't like having us on the course (when they do allow us to enter). We try to be cool about our boat's performance but it's fun to see our boat with three sailors on board match or exceed the bigger boats upwind performance in all conditions (where they have 8-12 sailors on board). We find it silly they cannot just accept us like any other boat (especially after we have proposed to them that we have a multi-rating for light and heavy air to keep it fair).

Same everywhere. "most don't like having us on the course"

Even if we stay out of their way and tack early rather than enforce right of way and always sail under them etc. they still wish we weren't there.

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When we first started sailing our Sprint 750 on the lake in 2007, we were told we were not welcome to mix it up with the monohull boats in PHRF racing because our boat handled poorly and sailed different angles. Now that we've proven we can sail the same angles upwind, sail the same angles as any other sportboat downwind, and tack as fast or faster than any keelboat, their case to exclude us is significantly weaker but trust me most don't like having us on the course (when they do allow us to enter). We try to be cool about our boat's performance but it's fun to see our boat with three sailors on board match or exceed the bigger boats upwind performance in all conditions (where they have 8-12 sailors on board). We find it silly they cannot just accept us like any other boat (especially after we have proposed to them that we have a multi-rating for light and heavy air to keep it fair).

Same everywhere. "most don't like having us on the course"

Even if we stay out of their way and tack early rather than enforce right of way and always sail under them etc. they still wish we weren't there they were not so deeply committed to a monoslug.

there, fixed it for you. ;)

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