Canting Keel Monos vs Multihulls

[Joe6]

Compareing monos to multihulls is like comparing apples to oranges. The only similarity between the two is that they both float on water an have sails. To try and compare the performance of the two, side by side is rediculous, it dosent take a scientist to to see that. The two can simply not be evenly compared. The mono has to drag a significant chunk of lead beneath it to carry any amount of sail adding drag and displacement.

That said when the two are looked at individually, developments made in the last few years have resulted in performance gains that ten years ago many would have thought impossible.

As for a VO 70 hitting 40kts, I read 30-35kts in Seahorse. Even if this was'nt sustained it is amazing none the less. It is also my understand that ORMA 60's can attain these speeds routinely.

Monos and multis? Different animals altogether.

As fo the VOR in general one of the coolest things to come out of it in my opinion is the intended sideshow, the VX40's. I've been watching online, exciting racing! And I'm not really into multihulls, a real eyeopener!

Joe

 

[Joe6]

Doug,
Although I think foilers are cool and have followed Rohans developments when they come about in sailing mags, I'm not sure the sailing community on a whole even considers them to be boats.

Joe

 

[Doug Lord]

"What is the future of canting ballast? Post #1

Mr. Hough, the numbers don't add up if you use the wrong ones. For some future thread I'll get into it in much more detail but a 60' ORMA tri will weigh between 12-13000 pounds. A 60' monofoiler- which by definition must be selfrighting- would weigh around 14,000 with the capacity to add up to 3-4000 pounds water ballast. Ballasted up in the same conditions an ORMA tri flies the main hull it would weigh close to 18,000lb. At it's maximum weight it would still have 40% or so more sail area per sq.ft. of wetted surface even though it would have about 16% less overall sail area.
You have an excellent idea in having a multihull sail on only two foils; if you look at the picture of L'hydroptere in the new Sail it is doing just that. A monofoiler keelboat will not be faster than a good multifoiler in any condition.The definition of monofoiler is "a monohull foiler" and if it is a monofoiler keelboat it must be self-righting(my law).In my opinion, there would be little point in using movable ballast if the thing did not automatically right itself from a knockdown or pitchpole. If this technology is proven ,as I think it will be, conventional multihull speeds will be possible in a self-righting monohull for the first time.
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My only point in this whole thread was to show that the story on the "future of canting ballast" has not yet been written as opposed to the slam dunk "multihulls will always be faster" mindset evidenced in some posts.
I would have loved to hear Juan K answer the original question technically as opposed to the way he answered it. He didn't so I did and I think I've showed that there is a lot more to the story of "canting ballast" still to come.

 

[Doug Lord]

Changes in Attitude ARE the future....

Doug,
Although I think foilers are cool and have followed Rohans developments when they come about in sailing mags, I'm not sure the sailing community on a whole even considers them to be boats.

Joe

-------------------------
Joe, you're probably right but a number of us worldwide aim to change that in dinghies, keelboats and in multihulls. I predict that many who now harbor darkside anti-foiler sentiments will change their attitude once they get up close and personal with a well designed mono or multifoiler.

 

[Dan S]

Joe, you're probably right but a number of us worldwide aim to change that in dinghies, keelboats and in multihulls. I predict that many who now harbor darkside anti-foiler sentiments will change their attitude once they get up close and personal with a well designed mono or multifoiler.

OK Doug turn off Star Wars and step out side.

You make so many comments like this, that it’s not surprising people question your mental health.

 

[Chris Ostlind]

Love Affair

Joe, you're probably right but a certain dude with worldwide desperation aims to change that in dinghies, keelboats and in multihulls. I predict that the few who now harbor darkside hyper-foiler sentiments will change their attitude once they get up close and personal with a well designed, non-foiling sailboat of any kind.

Oh, sorry, that was meant for a different thread.

Funny stuff lately and the more I read from Doug's writings, the more it dawns on me that I've seen this performance before. I'm thinking of the way that the well-used groupies used to write letters to Rolling Stone Magazine back in the seventies when Led Zeppelin was at their zenith.

For some, the rush is in the need to be a part of something , to coin trendy phrases that they'll later haul-out at a BBQ so they can be seen as somebody important. Yet, when you dig down into their substance, you find the same thing that is inside the buoyancy pods on the oft mentioned hyper foiling, techno dragons that had but a flicker of a moment in the history of developmental sailboats.

Like Doug says, "it's only a matter of time" except in this case, the time signature is actually about the duration of the technology he is blowing-up over. Oh, don't worry, guys like the Lordster will surface somewhere among the weeds along the shore, get themselves together, brush off the slime and get back to work again, sporting a new hairdo and a whole new idea about boating that only they saw coming.

And yes, you can quote me on this. Doug will get another short term love affair with technology, his only mistress, and he'll rave about it until it, too, goes broke and sends him packing. The big tiff with the foiling crowd is but the tip of the iceberg in Doug's nasty, and very public, breakup with those guys. Why do you think he's all abuzz with the hunky, canting bi-foiler down the street that is bigger in every way than his small foiler, "used to be" mistress?

 

[rayaldridge]

Maybe I'm dumb, but it's hard for me to see how foilers even enter any debate about the relative merits of monohulls and multihulls. My understanding of foilers is that the hulls only serve as a way to hold the foils in the appropriate position until lift-off (and, I guess, as a platform for slowspeed maneuvering.) So why does it even matter whether there are one or more hulls functioning in this temporary manner?

 

[Doug Lord]

1,2 or 3

Ray, perfectly logical question. In small boats it appears that a configuration like the Moth using just two foils is very fast-faster than many multihulls much longer than it is. It hasn't been done yet but perhaps a small multihull could be designed to sail on just two foils but it would probably be heavier than a 2 foil monofoiler if both were unballasted.
In this thread, in the first post, the question was asked regarding the "future of canting ballast"; canting ballast is usually associated with monohulls and the question developed whether or not a canting ballast boat could ever be as fast as a multihull. Thats where foils may come in some day-allowing a canting ballast monohull to go faster than currently possible-possibly as fast as some multihulls that have "foil assist"(like ORMA trimarans) but not full flying hydrofoil multihulls. Multihulls that fly on hydrofoils may be the fastest of all.
But should a canting ballast monofoiler work it will have one advantage over multihulls:it will be self righting. But we'll have to wait to see how this plays out....

 

[Chris Ostlind]

From There-on, It Went Squiggly

This topic took a decided detour at post number 12 when the Dougster mentioned his old stand-by... that being the absolute need to glue-on a pair of foils to any boat sailing and call it better.

Doug, this should have remained a grounded discussion on the viable realities of what is at hand and not on what could be sometime in the smokey future of Foilmania. Not all boats will benefit from foils and the jury is certainly out as to the current benefit for those that do use them.

Foiling could just as easily turn out to be the bad branch on the evolutionary tree of boating, much like a Chimp who was born with no thumb. This techy stuff comes and it goes throughout history and that is something that no amount of hyperbaric chamber method acting will cure. Not today and not in the future.

My crystal ball says that the price of the resource that is used to make the foils...namely carbon and epoxy, will get so damned expensive relative to the customer's ability to pay, that foiling will literally price itself right out of the potential marketplace.

That puts everything right back to the simplest form of the discussion, which is; the age-old cocktail hour argument of a couple of multi-thousand year old boat forms and which is better for a given task.

So, for me, register my apologies for distancing this crew from the threaded task at hand and let's continue with the talk... sans the whole foilista enchilada that Dougster threw on the table. It's just not appropriate or connected to the topic.

Moving on... Log my official protest to the assumption that, and I quote here from our distinguished member, jehardiman at Post #11,

the only reason that a cat or a tri has any major ocean ability is due to one thing: Modern composites.

There's lots of reasons to find that assumption off track, but for the sake of simplicity.. let's just put the dance floor at the correct angle with this observation... the same can be said for modern monohulls, especially those with canting keels and Super Burger sized rigs.

So, what exactly is the point in the statement?

 

[jehardiman]

Moving on... Log my official protest to the assumption that, and I quote here from our distinguished member, jehardiman at Post #11,

the only reason that a cat or a tri has any major ocean ability is due to one thing: Modern composites.

There's lots of reasons to find that assumption off track, but for the sake of simplicity.. let's just put the dance floor at the correct angle with this observation... the same can be said for modern monohulls, especially those with canting keels and Super Burger sized rigs.

So, what exactly is the point in the statement?

First of all, I don't have enough grey hair to be distinguished...

Second, lets step back and look at this objectively. I please ask every one to read the whole argument through before composing a reply....Most of what I’m going to say is taught in ship theory courses and I’m going to speak in generalities about hull types, but you can always argue the envelope edges and quriks

There are some basic points that all vehicles (sea, land, air, and space) share.

a) The whole reason for a vehicle is to move people and goods from one place to another. The ability to do this is called the transport capacity, generally expressed in weight and distance per unit time, say ton-knts/hr. Say a 30 knot log proa can carry 1 ton or 5 knot lapstrake cog can carry 6. Both would have a transport capacity of 30 ton-knts/hr

b) For a transport system the effectiveness is how much weight can be delivered. Using our tri and scow above I want to deliver goods to the next island over, 100nm away and the crews are the same size. To deliver 100 tons of good, it takes the proa (including 1 hr port time) 99.5 (100 tons) trips at 32 days. The scow takes 17.5 (108 tons) trips at 30 days. If we also consider that the crew consumed 100lbs of food per day the proa only delivered 98.6 tons while the cog delivered 106.6 tons. The cog was the better delivery system at an average of 3.5 tons/day over the proa at 3.1 tons/day. This is why ships need to get bigger vice faster, which becomes important when we consider materials.

What does this have to do with tris, cats and monohulls sailboats? And in particular, the topic I addressed, ocean crossing and modern composite materials? The answer is simple: vessel size and weight is determined by the required transport capacity and material strength to weight ratio. Therefore transport capacity and material selection sets the ability to carry sail and resistance, and therefore the speed, of a given hull type.

Lets put some general numbers in. Say I want to non-stop circumnavigate in ~ 100 days in a small boat. Stores consumption is ~5 lbs/person/day and water/liquids about 16 lbs/person/day (2 gals, after about ’95 this weight goes to a fixed weight of about ½ gal or 4 lbs/person/days of longest leg with the introduction of water makers). So for a solo voyage I need ~2,100 lbs stores and about a 1,000 lbs spares and crew and effects at ~ 350 lbs/ person. Now for a modern mono racer in the 30 foot range, hull weight is ~20% and ballast is ~50% of total displacement leaving 30% for transport capacity. 3450/0.3 =11,500 = 5.1 tons displacement ~180 cf… say Lwl of 26 ft, Bwl 9, canoe draft 1.5. So to get my 27,000 nm in 100 days, I need an average speed of 11.25 knots, something I realistically cannot achieve in that small of a boat. Therefore, the boat has to get larger. Now we all know that the displacement, volume, and loads increase with the cube, but the strength only increases with the square. Therefore if I make the boat half again as large, the displacement is multiplied by ~3.4, but the hull weight is increased a factor of ~ 5.1. The new 40 ft Lwl, vessel is 39,000 lbs, of which 30% is hull, but my required transport capacity is now reduced to 9%, allowing me to up my ballast to 61%. But that’s OK, because as it gets larger, the excess transport capacity rolls over into more ballast, resulting in greater speed. Now we are getting into the mission achievable range.

For a modern cat in the 40 foot range, the transport capacity is ~ 20% for a hard deck to ~40% for a soft deck and tris are even less. (there are lots of reasons for this most having to do with habitability and crossbeam loads). So I would need a displacement of ~ 8625 lbs on a soft deck cat, which implies a length of 33ft, a hull beam of 1.6ft, and a total beam of ~20 ft. Now a hull beam of 1.6 feet is un-livable, so I need to increase the hull beam to 2.5 feet, which is tight but doable. This increase the length and beam to 51ft, beam to 31ft and displacement to 32,000 lbs. However, because of the design of a cat some of the hull loads do not increase with the cube, but with the scale factor to the forth because of the loading of the moment in the cross beam. If we assume that the cross beam is half the structure weight, then the new structure weight is (W/2)*X^3*(X^3/X^2)+(W/2)*(X^3)*(X^4/X^2) =2587*3.8*1.56+2586*3.8*2.43=39214 lbs. Now this structure weight exceeds the total new displacement. The size expansion to hake the hull livable is unviable if the material is unchanged.

Simplistic calculation…YES!

But what it points out is that given a constant material strength to weight, the basic design of all vessels is limited. This is why until the introduction of iron and steel, you never saw a wooden ship over ~300 ft. And why cats were limited to small open vessels in temperate climates until the introduction of light-weight high-strength composites. If we redo the above calculation and say that the material has half the weight for the same strength the answer is different as the hull weight would then be ~20k lbs which would make the vessel design viable.


Lets look at some examples over the years;

Circa 1500, NINA (mono) vs HOKULEA (cat). NINA was about 68x18, 37 tons, 18 men, made 3300 miles in 36 days out, 3100 back in 30 days back, 4.0 knots. HOKULEA is 62-4x17-6, 11.1 tons, 15 men, made 2400 miles 34 days out, 22 days back, avg 3.5 knots. NINA was held back by the slower SANTA MARIA outbound, and had to carry ~40 men back as well as all the food for the entire 9-month voyage.

1973 GBII vs PEN DUICK IV (tri). GBII, mono 78x?, 40? tons, 15? Men, say 27500 in 144 days, 7.9 knots, 3 stops. Pen Duick IV (as Manureva), tri 70x35, 8 tons, solo, say 27500 in 168 days, 6.8 knots, 1 stop.

1983 CREDIT AGRICOLE III mono 56x?, 11.5 tons, solo, 27100 official miles in 159d 02h 26m 01s, avg 7.1 knots, 3 stops . NIKE III, mono 44x13, 13.5 tons, solo, 28,975 nautical miles with actual elapsed sailing time of 203 days, 2 hours and 1 minute , avg 5.9 knts, 3 stops.

1986 KRITER BRUT DE BRUT, tri 77x?, ? tons, solo, 26789nm @ 8.6 knots average, 3 stops.

1994 ENZA NZ, cat 92x , tons, ?men, 26,414 @ 14.7 knots, no stops

2001 PRB, mono 60x?, ? tons, solo, 26,010 @ 11.6 knots, no stops

2002 ORANGE, cat 112x53, ? tons, ?men, 23,800 @ 13.8 knots, no stops

Three big things jump out. 1) Prior to the mid 1980’s there was no advantage to multi-hulls in ocean crossing. 2) Crewed is faster, and 3) the huge increase in cat/tri size in the last 20 years. Given that the transport capacity increases linearly with manning, it is rather obvious that only very large multi-hull can support those types of weights. And to support the large loads of a large multi-hull within the necessary weight, high-strength low-weight material is required. So…..

the only reason that a cat or a tri has any major ocean ability is due to one thing: Modern composites.

QED….

 

[Chris Ostlind]

Loaded

Hi je.

Nice arrangement of thoughts, but to get this on track with the thread and its original premise, where is the business of including the canting keel setup for the monohulls in question?

I'll quickly give you the points on the fact that monohulls are typically better load carriers, but that's not what the thread points us to.

For the modern monohull with a canting keel to be competitive with the modern multihull, it's also necessary that it be built from modern composites. From a materials basis, it would seem that this argument is pretty straightforward. Well, it's straightforward, unless you can point me to an example of a swinging keeled racing craft of significance from before the era of modern composites. And if such a critter has existed, what kept it from totally dominating the racing landscape and becoming the most fabled boat of all sailing history? It wouldn't be The America's Cup, it would be the Swinging Keel Cup. Alas, I don't think there is one to haul-out as an example.

It is with the use of modern composites, that such a technological example can even exist and be competitive. Additionally, and you know this as well as anyone around, je, you don't have to have as big a multihull... made traditionally, made modern, whatever, to totally kick the crap out of a comparably built monohull. I invite you to pick the fastest displacement monohull you can find and with a smaller LOA multihull, my driver will beat you every time. Load carrying capacity be damned... we're racing, not load carrying. OK, there is one exception and that would be in extreme light air and then both boats are in trouble

None of these boats are carrying anything resembling a load, as you describe the task. In fact, they're stripped-out shells with but the minimum of creature comforts and supplies for the task at hand. Everything is there in the pursuit of speed, so the only purpose for structure is to accept ever-bigger sail carrying capacities. As race boats, they do not have to live beyond the assigned duties of the task at hand.

I recognize your arguing point on the load issue, but I'm just being a little obtuse by sidestepping the technical argument in favor of the more practical aspects of what boats are used for. The point being, there is a lot of unused load capacity in all racing boats and that is the root from which this discussion sprang.

Now about that original premise;

Quote
the only reason that a cat or a tri has any major ocean ability is due to one thing: Modern composites.

In your argument you very carefully show that many multihulls had major ocean capabilities well before modern composites were introduced. That makes for an interesting conundrum, from my perspective. You have more or less proven my point on your own. Your statement doesn't say at what speed, what load carrying capability, what ocean or anything really of detailed significance. It's just a flat, very generalized statement.

And what exactly is a major ocean? Or is that major as in the descriptive? Kind of vague in that regard without further iteration.

Prior to the 80's there was no advantage to multihulls for ocean crossing.

By saying there is no advantage, are you also indirectly implying that multihulls were at a disadvantage? If so, then I disagree.

The vast exploration and settlement of the Pacific Ocean was done almost exclusively via multihulls, and it was done long before the Northern Europeans even had a ship with which to do it. This is something like half of the face of the earth, and these guys accomplished this feat when Europeans were pretty much screwing around in the Mediterranean with oar powered ships. Quite a product success story for a craft in which there were no oceanic advantages. Perhaps you can tell me just what monohull had such remarkable superiority at sea, that the culture from which it came had expanded its influence over half the globe by the first two hundred years AD?

If mulithulls have no advantage, how did they manage to accomplish such a daunting task. The Hawaiian Island settlement, as one of the last island chains to be inhabited in the Pacific, somewhere between 100 and 500 AD, also proved to be one of the toughest due to its remoteness. Again, just what, specifically, about that ocean-going prowess represents a design disadvantage?

This has been fun, je. Thanks for the measured and thoughtful collection of ideas.

Chris

 

[jehardiman]

Chris; the Polynesians could get away with using primitive, low capacity, multi-hulls because of the environment they faced. If a multi-hull was inherently superior to a mono, the whole world would have been using them, just like the whole world used the ax and adze (Polynesians never developed the saw). The Pacific was named so be cause the European mariners that saw it were so astounded that a body of water could be that easy to sail. And it is a well argued premise that KON-TIKI took longer to make the crossing because they tried to sail the raft, which worked against the current, rather than let it just drift. If the log cat or proa was so superior to a mono, then why did the Europeans discover the Pacific vice the Polynesians discovering the “Stormy”. Anyway, that has social, economic, and cultural issues that need not clutter this discussion. In the final engineering analysis, it is only the development of modern high-strength low-weight materials that allow multi-hulls as we know them now to exist at the length/weight/sail area that give them their performance in the unchanging ocean environment. This applies not only to the failure of multi-hulls to be successful in the 19th century, but also to the failures of other radical craft that tried to increase speed under sail such as 18’s, sandbaggers and canting keels (BTW, the canting keel pre-dates 1900, the problem with it was the inability to seal the joint resulting in poor arrangements. I know of one vessel, I’ll need to find the reference, ~40ft that was built with a canting dagger board. The WT case occupied the whole of the middle of the hull, resulting in a successful solution, but unsatisfactory arrangement. Additionally, many of the early AC’ers were centerboarders, until the rules changed to prevent them, and other technological advancements, from dominating what was and still is a rich mans dalliance.)

From a technological point, I still stand behind my response to the original thread question. Re: Juan Kouyoumdjian replied to the question "What is future of canting-ballast technology?"

Our sailing community is divided, and choices are made on style or fashion; otherwise we'd all be sailing multihulls

What I originally responded to was the phrase “Our sailing community…”. I believe he was talking about the high-speed route racing community, not the whole sailing community in general. A multi-hull is not the answer to every sailing problem, however well many may think they dominate the genera. There are many reasons for this, some economic based upon the cost of delivering the accommodations desired, some about the size of facilities required to support multi-hulls, some about the hydrodynamic qualities of multi-hulls in given environments. Not everyone needs, or wants, a VX40 for an afternoon sail. Indeed, not every racer needs a multi-hull. For a Wednesday night beer can race I’ll take an el toro and you can charter ORANGE II, with crew, and I’ll wipe you up, FTF and corrected, while kicked back drinking a Saint Stan’s out of the cooler in the bow…..if I get to pick the yacht club venue.

Posturing aside, there is no doubt that multi-hulls meet some design requirements. But they do not meet all of them. In the final engineering analysis, I would not choose a multi-hull as the optimum hull form for a sailing yacht given an unrestricted design brief. And as I said in my first post …

Remember, the only thing a Naval Architect has to sell is his opinion. Because, in fact, the answer is always " It depends....".

 

[marshmat]

Remember, the only thing a Naval Architect has to sell is his opinion. Because, in fact, the answer is always " It depends....".

So true..... we often forget that in the middle of all this arguing, there is no perfect solution for everything.
Circumnavigating the globe? I can't think of anything I'd love more than a (slightly beefed-up) VO 70 for this. I'd never take a VX 40 on this trip, but on a three-hour course where speed is everything, that would be a great boat. It all depends on what you do with it.
Now as to the future of canting ballast. I think there are still some technical issues that need to be worked out, such as the tendency of keel hardware to fail. (Think of how many VO 70s didn't have keel trouble...) There's also the philosophical issue of running an engine all the time; I don't think it would ever be fair to give a sailing record to a canter unless there's a 'power assisted keel' note beside it. But on the whole, the growth of canting ballast technology is probably the biggest single development in monohull sailing since the invention of the freestanding wingmast (which, for some reason, is still not allowed by many rating rules). I'd never buy one for myself; the huge draft and the complexity of the keel are big turn-offs for someone who uses a boat mainly for fun. But there is a lot of potential there- yes, there will always be multis that can cream canting monos, but for open-ocean mono racing the canting keel has a lot of untapped potential. In the end, ultimate speed doesn't really matter- what matters is how many people see the boat, watch the race, buy from the sponsors.

 

[Chris Ostlind]

Thrashed

Hi John,

the Polynesians could get away with using primitive, low capacity, multi-hulls because of the environment they faced. If a multi-hull was inherently superior to a mono, the whole world would have been using them, just like the whole world used the ax and adze (Polynesians never developed the saw)

The Polynesians didn't need the saw. Probably never will, from a purely cultural point of view. The saw is a European/Western civilization pre-supposition for advancement of the trade. Mostly commercially driven, by my analysis. They seem to be doing things just fine by my account of their culture. When we stretch this idiomatic discussion out about four hundred years, the Polynesians will still be doing their thing rather successfully, and we will have blown our sad wad and be well into a cultural retreat.

It's a cyclical thing. The Egyptians did it, the Romans did it, the Greeks did it, most of Europe is now doing it and so it goes on across the Atlantic to North America. We are very close to having had our day in the sun historically and there's little that any of us can do about it except learn from the, so-called, primitives of this planet and salvage some form of self respect along the way.

I did, however, like the way you dug deep and stepped-up with the El Toro match against Orange II. Though it would take the El Toro about an hour to just get to the point where it had passed the bows of the Black and Orange boat stalled-out on the start line while observing a looong moment of respect for the tiny boat in its lee. I'd be more inclined to bring a 3 meter trimaran for that situation. Mano-a-mano. But that's for another day, as they say.

A multi-hull is not the answer to every sailing problem, however well many may think they dominate the genera.

I do recognize that there are many situations in which the correct boat for a specific task is not a multihull. The Exxon Valdez comes to mind, but I'll pass on that example. Certainly some very good work is being done to advance the science and understanding of better forms along with simpler, I'd like to say, technological solutions, but that isn't where we really need to go.

I have thoroughly enjoyed the repartee. Your knowledge of technical issues is remarkable and I have learned a lot while reading your postings. Thanks for being such a good sport in all this.

I'd say that the topic has pretty well been tossed by now, wouldn't you?

 

[Alan M.]

Some really good laughs in this thread. Thanks guys. I am still wondering how the possiblity of a foil assisted moth being fast has anything to do with canting keel monohulls. Does a moth carry ballast? (Apart from it's crew) That is the reason mono's (larger than dinghy size) don't and won't sail as fast as multi's - they carry tonnes of lead to keep them upright - given the same power, the lighter vehicle will ALWAYS be faster.