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Old 21-06-2012, 22:56   #1
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Mono vs. Multi - Sailing Ability

I've done some thinking and reading on this recently, and have hit on what I think may be a real revelation about this.

We often see the debate of sailability of monohulls over multihulls, but I think this is severely mistaken thinking, which likely explains why the conversations never get anywhere.

I'd be interested here yays and nays on this theory:

I believe that, if a given monohull were constructed to the same feature levels of a given catamaran, it would likely point just as poorly or possibly worse than the catamaran.

Using a typical charter cat as an example, what if a monohull were built to the same standard
- a large, brightly lit topdeck saloon
- a short, long keel to reduce draft
- sufficiently sized to produce similar interior space and comfort
- otherwise equally rigged in all similar respects

Such a boat, with high windage on the topdeck cabin, and a short keel, and a wide, rounded beam would probably do no better than 45 degrees to the wind, and likely at a slow speed to boot!

Conversely, if a catamaran were built to a monohull standard:
- Deep keels, possible with retractable keels/boards
- Low, streamlined deck with only stepdown cabin in the hulls
- Narrow low hulls designed to optimize speed and reduce windage

Then wouldn't this catamaran point just as well as the comparable monohull? And given the lack of a heavy underwater ballast, likely outperform progress over ground, even if it did point slightly below?

If this theory is right, then there is no real "monohull vs catamaran" debate to be had. It might spoil some people's fun, but it seems that this is really about high-windage small-keel boats vs low-windage deep-keel boats, whether multi or mono!

Anyway, I'd like opinions as to whether I'm all wet on this or not.
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Old 21-06-2012, 23:04   #2
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Re: Mono vs. Multi - Sailing Ability

I think these Cat verses Mono posts create a 'storm in a tea cup'. I love seeing people out in thier boats whatever it may be ... just having good fun. I REALLY do not buy into this whole mono points better than cat thing ... just today we outpointed one sailing to Deadmans Bay in BVI ... the sailor came up to me, shook me by the hand and said he could not believe how much higher I got to wind than he could. I think it's how the boat is balanced and I would be more than happy to be proved wrong as we do not sail to win races ... we sail to get to places I equally enjoy sailing with my buddies on thier mono hulls but as I said ... I do not buy into the higher pointing ability of a mono verses a cat!
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Old 21-06-2012, 23:12   #3
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Re: Mono vs. Multi - Sailing Ability

The term sailability probably has as many definitions and weighting as to what is important as there are boat designs. Sailability depends on who ya ask.
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Old 21-06-2012, 23:16   #4
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Re: Mono vs. Multi - Sailing Ability

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Originally Posted by ArtM View Post
Anyway, I'd like opinions as to whether I'm all wet on this or not.
Yes, I think you're all wet on this.

Spend some time in a beach cat, and you will soon discover the holes in your theory.
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Old 21-06-2012, 23:21   #5
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Re: Mono vs. Multi - Sailing Ability

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Yes, I think you're all wet on this.

Spend some time in a beach cat, and you will soon discover the holes in your theory.
What would be an example of a "beach cat", and what would be a comparable monohull to sail-test against it?
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Old 21-06-2012, 23:22   #6
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Re: Mono vs. Multi - Sailing Ability

Do you mean like a Hobie 14 or 16? Or do you mean a beach cat with daggerboards and very fast hulls?..like a Tornado or Class D cat? I don't think there is any monohull that a class D cat cannot beat to a weather mark. Off the wind and its no contest. I think the OP meant more the latter than the former.

Design it right and it can be extremely fast on all points of sail.
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Old 21-06-2012, 23:26   #7
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Re: Mono vs. Multi - Sailing Ability

Have a look at the current AC45 catamarans being sailed by the best sailors in the Americas cup series, that should answer your question on cats sailing performance.
As for going the other way I don't think there is a limit on how badly a boat can be designed.

I cruise in my cat and race my mono but that's just my preference no scientific theories there.
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Old 21-06-2012, 23:30   #8
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Re: Mono vs. Multi - Sailing Ability

A beach cat would be a classic example of getting close to the wind (with dagger boards of course) ... I raced Hobie tigers which eventually led me into my cruising life. There is a classic example of when one shifts body weight around (eg body weight foreward points higher) ... similar on a cruising cat (me thinks!) ... boat balance in the water plays a role. I think I mentioned it before on CF, that when we have a long upwind sail we fill our water tanks and get weight on the nose. The boat climbs better that way! Downwind is a different story altogether!
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Old 22-06-2012, 07:01   #9
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Re: Mono vs. Multi - Sailing Ability

There are lots of examples of your design differences - a 46' Morgan OI as a charter mono vs a 45' Outremer as a performance cat come to mind as one example. A 12M Catalac vs a J40 as a reverse example.

In the real cruising world, looking at the boats people have chosen to cruise with and how they are prepared and loaded for cruising, there is no difference between cat and mono performance (they both leave a lot to be desired). If anything, cats outperform in this arena simply because they are more modern designs and construction techniques compared to the Pearsons, Liberty's, Mapleleafs, Out Islands, CSY's, Gulfstars, Whitby's, etc that are extremely common choices for cruising boats. And most cruising sailing is downwind, where even the doggiest cat is going to outperform all but the fastest monos.

The topic is mostly of interest only to the internet forums.

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Old 22-06-2012, 17:51   #10
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Re: Mono vs. Multi - Sailing Ability

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If anything, cats outperform in this arena simply because they are more modern designs and construction techniques compared to the Pearsons, Liberty's, Mapleleafs, Out Islands, CSY's, Gulfstars, Whitby's, etc that are extremely common choices for cruising boats.
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Well, this is kind of where I'm going with this. I'm thinking that cats, given all other things equal, may very well point BETTER than monohulls, and thinking that if presented the question "Why do you like a catamaran" I'm going to say "because they point better than monohulls".

If they choose to challenge me, I'll ask them to show me a 65' monohull with a 3' draft that can do better than 50deg to the wind!
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Old 22-06-2012, 18:38   #11
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Re: Mono vs. Multi - Sailing Ability

Well, I have a stone-axe Wharram catamaran that I've been anxious to take out sailing after working for a couple of years on the interior. There are still a lot of sharp edges, but it has no dagger boards or dropping center board, nor any mini keels. I am concerned about windward performance, mostly to ascertain what I can do with it, some actual numbers.
I've gone out now a few times and had to fix some shakedown items. I've noticed when I was fooled by aparent wind on the way back to the inlet, I had to come close hauled to make it. I had to use manual steering because the hydraulics had failed due to a twisted seal. I found a lot of pressure on the helm. The rig had been reduced by rolling up the 500 ft genoa, and I hadn't reefed the main, but I was mainly trying to simplify things to 2 sails. The boat sailed right to the mark, although the rudders were making a lot of vortex.
I think the windward equation is dependent on adequate surface area below the waterline, such as a centerboard or keel, and not overpowering it with sail area. I've been on full keeled monohulls that had problems coming about and making good windward, but there may have been barnacles involved. My guess is that with good sails and some fins down below, a catamaran could go right to windward just as well as any monohull. Remember that aparent wind does not only come up in light winds. A catamaran going only 10 knots or so, will develop a 10 knot headwind combined with the true wind. It makes sense to plan courses off the wind, get away toward your planned destination.
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Old 22-06-2012, 18:41   #12
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Re: Mono vs. Multi - Sailing Ability

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Originally Posted by ArtM View Post
Well, this is kind of where I'm going with this. I'm thinking that cats, given all other things equal, may very well point BETTER than monohulls, and thinking that if presented the question "Why do you like a catamaran" I'm going to say "because they point better than monohulls".

If they choose to challenge me, I'll ask them to show me a 65' monohull with a 3' draft that can do better than 50deg to the wind!
We get it. Insecure about your catamaran. That's ok, but it's a faulty comparison. Show me a 65' monohull anywhere with a 3ft. draft. Physics comes into play and makes some things impossible. It's like saying "show me a catamaran with one hull that can do better than 50 deg to the wind" Be happy with what you got, or sail as many monohulls and catamarans as you can and come up with a real opinion. Speculation is just that, and without experience, it's just guessing
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Old 22-06-2012, 20:37   #13
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Re: Mono vs. Multi - Sailing Ability

Ahoy Elliebell,
Here is your posting:
We get it. Insecure about your catamaran. That's ok, but it's a faulty comparison. Show me a 65' monohull anywhere with a 3ft. draft. Physics comes into play and makes some things impossible. It's like saying "show me a catamaran with one hull that can do better than 50 deg to the wind" Be happy with what you got, or sail as many monohulls and catamarans as you can and come up with a real opinion. Speculation is just that, and without experience, it's just guessing

It's not "just guessing", but I've been sailing for over 50 years and I love keelboats, especially with a lot of teak, and bronze, and polished brass, but I like to move when I sail.
I agree, this posting almost seems like a troll for us to come out and spew our guts.
The problem is trying to be nice to my keelboat friends, who have some very nice boats. Classics, and nice to be down below at the dock. But they are angry at the new plastic racers, who try to show them up, once they get out of the inlet.
I went for a catamaran, that is like a German submarine down below, but even singlehanding it, once I get the sheets reeled in, I've got a lot of local competition, NOT!, they bear off, they tack away, they don't want to sail at, what 8, 9, 10 knots?
I still feel like I'm dragging back, I mean the speed limit on the Key Bridge is 50, ain't it?
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Old 23-06-2012, 06:38   #14
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Re: Mono vs. Multi - Sailing Ability

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...I'm thinking that cats, given all other things equal, may very well point BETTER than monohulls...
It is only a case by case thing. Much of the upwind sailing ability can be contributed to the big nut behind the wheel and not to any other part of the boat. If you put an extreme 40 helmsman on a Morgan OI vs. your average cruiser on an Outremer, my bets will be on the OI.

Like I mentioned earlier, there are a lot of monos that can not sail upwind well by design and a lot of similar cats. And vice versa. And then you factor in cruising trim and condition. You can pair up any of them to make either side of the windward argument.

Off the wind, a multi is going to dominate in both speed and comfort - particularly deep down wind and in large seas.

Who cruises upwind predominantly?

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Old 23-06-2012, 13:25   #15
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Re: Mono vs. Multi - Sailing Ability

It wasn't intended as a troll. Maybe another way to say this is that if I had a catamaran with keels as deep and topdeck as low and interspace as large as a given sailboat, would that Catamaran point as high, or possibly even higher than that Mono.

In other words, is it possible that mono's don't really have superior pointing ability at all, and further is it possible that a cat would have superior pointing over a mono with comparable design?
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