Mono vs. Multi - Sailing Ability

[maytrix]

Originally Posted by ArtM

You're not comparing monos and multis.

You're comparing low profile deep keel boats to high profile shallow keel boats.

Given similar livability and shallow draft features, the argument is that a multihull would sail with equal or better performance than the comparable monohull.

You've stated the conventional wisdom, but I'm arguing that it is incorrect. The fact that most mono are deep-keeled, and most multis are shallow-keeled is the source of the misunderstanding.

I contend that a deep-draft multihull would sail equally or better compared to a deep-draft monohull, assuming similar sail limits and top-deck design features (i.e. cabins, bimini's, pilothouses, etc)

And why do you think they are designed this way? If you make a deep drafted Cat with a low deck, you might as well be in a mono?

And I think a Mono with the changes you describe would be very subject to rolling over.. There's a reason they are both designed the way they are - why argue over theory? Seems rather pointless to me.

I feel like we might as well discuss whether or not a ferrari with wings would fly.

[ArtM]

Originally Posted by Bash

You're getting closer. If you want to argue that a beamy, shallow-draft monohull with excessive freeboard would sail as poorly as most cruising multihulls, I suspect that a great many sailors will let you win this argument.

That is exactly my argument, and that my conclusion is that sailing performance is NOT a consideration when choosing between a catamaran and a comparably configured monohull sailboat.

So why buy such a boat, knowing that it will have at least a 6' draft, when you can buy an equally capable, shallower draft, and more comfortable catamaran?

I'm also making the counterpoint, which is that a low-profile catamaran with a well designed keel/daggerboard system would likely outperform a similar monohull under many, if not most conditions.

[ArtM]

Originally Posted by maytrix

And why do you think they are designed this way? If you make a deep drafted Cat with a low deck, you might as well be in a mono?

And I think a Mono with the changes you describe would be very subject to rolling over..

Right. It would not only point abysmally, it would capsize on the first attempt.

Originally Posted by maytrix

I feel like we might as well discuss whether or not a ferrari with wings would fly.

I would love to have a flying Ferrari - it does not feel pointless to me!

And I will love having a spacious, stable sailboat with a large topdeck cabin without feel as though I had to give up performance or sailability to get it. If it only had daggerboards - which is why the gunboats have the performance reputation they do.

[D&D]

Originally Posted by Dockhead

there are no signs that mono sales are dropping off any cliffs.

Well, perhaps it depends on what is meant by "dropping off cliffs", but we are very reliably informed that the relative proportions of mono vs multi sales of new vessels here in OZ is shifting dramatically in favour of multi's. Based only on conversational 'research' (albeit with a source who is perhaps the best placed person in the country on this subject) and allowing for some drift in the memory of this ancient mariner, multi's represented ~5% of sales here 10 years ago and they now represent ~50%...and that sounds like a reasonable cliff to us.

On the other hand, perhaps the above may just be another reflection of all of us Down Under being upside-down?

Forward thinking, more likely...

[downunder]

Originally Posted by D&D

Well, perhaps it depends on what is meant by "dropping off cliffs", but we are very reliably informed that the relative proportions of mono vs multi sales of new vessels here in OZ is shifting dramatically in favour of multi's. Based only on conversational 'research' (albeit with a source who is perhaps the best placed person in the country on this subject) and allowing for some drift in the memory of this ancient mariner, multi's represented ~5% of sales here 10 years ago and they now represent ~50%...and that sounds like a reasonable cliff to us.

On the other hand, perhaps the above may just be another reflection of all of us Down Under being upside-down?

Forward thinking, more likely...

+1

[neilpride]

So why buy such a boat, knowing that it will have at least a 6' draft, when you can buy an equally capable, shallower draft, and more comfortable catamaran?

Probably because a Multi is expensive.
Comfortable? look we told you before, define comfort, many we love the way a mono deal with the sea conditions, meaning rolling and heeling.


I'm also making the counterpoint, which is that a low-profile catamaran with a well designed keel/daggerboard system would likely outperform a similar monohull under many, if not most conditions.

There is multis out there with this caracteristics , take a look at Outremers for example..

That is exactly my argument, and that my conclusion is that sailing performance is NOT a consideration when choosing between a catamaran and a comparably configured monohull sailboat.

It is and not, money isues, price, the quality of construction, maintenance fees, the simple dream for a monohull, or why you think people out there buy monohulls , no matter the size or the price?

If you cut the ugly cabin in a Lagoon you loose the Saloon and lot of living space, if you put long daggerboards in a Lagoon probably you increase the price, and probably some lazy couples dont want to deal with daggerboards, and if you put a long mast in a Lagoon maybe you are playing with the design limits, thats why all the boats are a compromise. Face it.

And there is out there a bunch of well designed centerboards monohulls , low draft, pointing well, and beamy.

[Dockhead]

Originally Posted by D&D

Well, perhaps it depends on what is meant by "dropping off cliffs", but we are very reliably informed that the relative proportions of mono vs multi sales of new vessels here in OZ is shifting dramatically in favour of multi's. Based only on conversational 'research' (albeit with a source who is perhaps the best placed person in the country on this subject) and allowing for some drift in the memory of this ancient mariner, multi's represented ~5% of sales here 10 years ago and they now represent ~50%...and that sounds like a reasonable cliff to us.

On the other hand, perhaps the above may just be another reflection of all of us Down Under being upside-down?

Forward thinking, more likely...

Cruising cats are popular in two places I know -- the Caribbean and Australia, which do not account for such a large part of the world market. Elsewhere they make up a stably low proportion of the fleet. In the UK, where I sail, which is the most sailing nation in the world, I guess that they must amount to 0.1% of cruising boats -- one out of a thousand, with no change I have noticed over decades. Although cruising catamarans have been produced in the UK for decades.

[Dockhead]

Originally Posted by ArtM

You're not comparing monos and multis.

You're comparing low profile deep keel boats to high profile shallow keel boats.

Given similar livability and shallow draft features, the argument is that a multihull would sail with equal or better performance than the comparable monohull.

You've stated the conventional wisdom, but I'm arguing that it is incorrect. The fact that most mono are deep-keeled, and most multis are shallow-keeled is the source of the misunderstanding.

I contend that a deep-draft multihull would sail equally or better compared to a deep-draft monohull, assuming similar sail limits and top-deck design features (i.e. cabins, bimini's, pilothouses, etc)

Mono and multi draft cannot be compared. The entire principle of stability between the types is different. Mono keels are ballasted. Multis don't have ballast at all, because they work on the principle of form stability. Since a fairly normal ballast ratio on a mono is 40%, multis can be much lighter. And since they don't require tons of lead to be hung at a geometrically appropriate distance from the boat's roll axis, the hulls can be shallower, reducing wetted surface. This is the whole advantage of cats, so a "deep draft" cat is an absurdity.

By the way, I am surprised that no one discusses the fact that these features give cats great advantages in motoring performance. Under sail in a mono, you don't really mind the extra horsepower you need to push more mass and overcome the resistance of more wetted surface since the wind is free, but under motor that costs fuel, noise, wear, etc. Cats are more easily driven and motor better. That's why no one cares all that much that most cruising cats don't go to windward very well -- you just motor -- no problem. I contend that modern cruising cats are mostly really motor-sailers.

[Therapy]

Originally Posted by ArtM

1) Not a troll, but this is strictly limited to cruising class multi-hulls 35ft and up and their comparable monohull boats (i.e. 45ft and up)
2) You might be right, but I'm not convinced. I would be interested to see sales growth figures for Monos vs Multi's in the cruising class in particular. Please share your source, if you have one. I speculate that multihull sales in the that segment will show substantial acceleration compared to monohulls. This should not be controversial at all, given that multi-hull designs are relatively new.
3) I disagree with this. I think that people buying cruising class vessels, often exceeding $300,000 USD in value, likely make use of spreadsheets or their equivalents in evaluating a boat purchase, unless the happen to live in the BVI and can view 100 different cruising boats for sale in an afternoon.

2 - The fact that cats cost so much more will keep a lot of people in monos.

3 - Spread sheets work up to a point. Your point may be farther along but most peoples points will end sooner as buying a item like a boat is more about love and infatuation = blindness. When you get that erection or the Admiral feels that warm, damp, cramp. The spread sheet is tossed or the data is "rearanged".

Just sayin'

[Therapy]

Originally Posted by maytrix

There's a reason they are both designed the way they are - why argue over theory? Seems rather pointless to me.

I feel like we might as well discuss whether or not a ferrari with wings would fly.

Erggzactly!

But you got here late and haven't paid dues.

[Dockhead]

Originally Posted by ArtM

That is exactly my argument, and that my conclusion is that sailing performance is NOT a consideration when choosing between a catamaran and a comparably configured monohull sailboat.

So why buy such a boat, knowing that it will have at least a 6' draft, when you can buy an equally capable, shallower draft, and more comfortable catamaran?

Because (a) 6' draft is not actually a problem anywhere; (b) it's not actually equally capable in most cases; (c) it's not actually more comfortable, depending on your preferences about motion.

Originally Posted by ArtM

I'm also making the counterpoint, which is that a low-profile catamaran with a well designed keel/daggerboard system would likely outperform a similar monohull under many, if not most conditions.

That's a bit like saying that a garbage truck -- if you would get the weight down to 1500kg, make it dramatically lower, and put in a 400 hp V8, would drive almost like a Ferrarri . Well, maybe, but so what?

A real performance cat with daggerboards will outperform just about anything on the water (leaving aside tris). It can even have a modicum of cruising ability -- Outremer. But the daggerboards are just one aspect of performance -- look at the hulls of an Outremer, then look at the fat hulls of a Lagoon. You could not just stick a daggerboard on that and magically get good sailing performance.

The problem with performance cats used as cruising boats is that -- like airplanes -- they are extremely sensitive to load. You would either have to have a very big one made all out of carbon (Gunboat), or be extremely disciplined -- no AC, no genset, no big tanks, no big inventory of spares, no major ground tackle, no loads of crap -- in order not to kill the performance and defeat the whole purpose of having it.

[D&D]

Originally Posted by Dockhead

the UK...is the most sailing nation in the world

According to the latest figures from the Marine Surveyors Association and the British Marine Federation, total boats in the UK represent ~0.8% of the population whereas the same figure in Australia is ~4%. The Surveyors also remark that "Australia has the world’s second highest percentage of boat owning people per head of population"...and we understand NZ may be the highest.

Admittedly the Australian and NZ populations are both much more concentrated along the coastlines than would be the case in the UK, but that is not particularly relevant in considering which might be the "most sailing nation".

That's all academic, of course. We are very happy to admit that the UK has perhaps the greatest marine history of any modern nation...and that history continues to be reflected in its strong sailing community today.

Anecdotally, we also know several very experienced UK sailors who would disagree with the suggestion that there has been "no change...over decades" in the proportion of cruising cats in UK waters. Our sources suggest the UK too is clearly experiencing an increase in the popularity of cats.

We say (again!) "Each to their own", but there seems to be no escaping the fact that the popularity of multi's is increasing.

[Factor]

Originally Posted by Dockhead

Cruising cats are popular in two places I know -- the Caribbean and Australia, which do not account for such a large part of the world market. Elsewhere they make up a stably low proportion of the fleet. In the UK, where I sail, which is the most sailing nation in the world, I guess that they must amount to 0.1% of cruising boats -- one out of a thousand, with no change I have noticed over decades. Although cruising catamarans have been produced in the UK for decades.

I think the Kiwis would argue with that.

[Dockhead]

Originally Posted by ArtM

Oops, I got your numbers mixed up. To address your "other" point, I've just never heard or read anyone commenting that they would have purchased a catamaran for cruising, but that it just couldn't hold all their "tons" of stuff. As a cargo vessel, they may not be they right choice.

But then I also believe that that the sailing cargo ship is obsolete, having never seen one operating in my lifetime - that doesn't mean it's true, though. Maybe the square riggers are making a quiet comeback!

Ah! This reflects a lack of cruising experience -- or maybe "misadvanture" is the better word.

Look around your house -- what do you see? If you sail long distances and spend weeks or months at a time on board, you will have more or less what you have in your house and in your garage, on board. Of course in less space you will be more disciplined and more selective, but you will not have an order of magnitude less stuff on board than at home. It is literally tons.

On my boat, just off the top of my head:

One metric ton of water, three-quarters of a ton of diesel fuel (when my tanks are full)
Half ton of ground tackle
Diesel generator weighing 500 pounds
Spare petrol generator
All kinds of shore power cords, extension cords, hose reels, etc.
Probably half ton of tools and spare parts -- filling an entire cabin -- including bench vice, drill press, complete inventory of power and hand tools, etc., etc., etc.
Complete kitchen inventory with dishes for 8 people, pots, pans, appliances, etc., etc., etc.
Complete inventory of winter and summer bedding for seven beds and umpteen pillows, etc.
Probably 100 pounds of books
Probably 300 pounds of various provisions at any given time
Several cases of wine plus a few cases of beer and a few cases of liquor
Two life rafts weighing 100 pounds each
Spare anchors and ground tackle
Probably 1000 feet of various kinds of line, some of it 1" thick
Complete inventory of weather gear">foul weather gear
Complete wardrobe of my clothing
Large collection of DVD's and electronic gear to watch them on.
Computers, printers, etc.
Snorkel gear for several people
Barbecue

and it goes on and on and on -- your whole life. I guess this must be 4 tons or so above light ship displacement, and nothing is really superfluous (I am pretty ruthless about throwing stuff out).

Propelling all that at double digit speeds across the ocean is quite a job.

Few people who spend extended amounts of time at sea have dramatically less than this. In a smaller multihull, it is a real problem to carry necessary cruising gear without severe degradation of performance -- it's one of the things owners talk about the most.

[Factor]

You need to get a Bendy 42 - it will do it easily apparently