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Old 05-04-2008, 08:11   #31
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If you think this gets old between mono, and cat owners. I am on another site for Cobra cars & replicas. The big block vs. small block goes on & on. That debate makes this seem tame....LOLOLOLOL

As far as comparing dollars to foot of mono, and cats. I think that donradcliffe is wrong. Just like the English language there is always exceptions to the rule. Research research research will find you getting much better deal than he quotes......just my humble opinion
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Old 05-04-2008, 09:07   #32
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Originally Posted by donradcliffe View Post
I discovered the reality of this the first year I raced cats--if one hull starts to lift and you don't dump the sheet, you are likely to go over, and stay over. The same thing applies to burying a lee bow.
What sort of cats did you race?
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Old 05-04-2008, 10:35   #33
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I don't have exact figures but quite a lot of cats have successfully completed circumnavigations without capsizing. I would imagine that the percentage of cats that start out and capsize is about the same as the percentage of monos that start out and sink
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Old 05-04-2008, 13:06   #34
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Originally Posted by donradcliffe View Post

It is an inarguable fact that catamarans are more likely to capsize than monohulls-- For at least the first 30-40 degrees of heeling, the more a monohull heels over, the greater the righting moment is, whereas the cat is exactly the opposite. I discovered the reality of this the first year I raced cats--if one hull starts to lift and you don't dump the sheet, you are likely to go over, and stay over. The same thing applies to burying a lee bow. No matter what the salesman tells you, these principles apply to cruising cats when things get hairy, as much from wave action as from wind forces. It is also a fact that, all other things equal, bigger boats are more comfortable and safer when things get rough, and out of control, and you are on the edge.

Now consider your choices--for $150,000 you can buy a 45 ft monohull or a 32 ft cat. When things get close to going out of control out there, your PF is going to be a lot higher on the cat, This translates to higher stress for you, which your partner picks up on. Even if your luck holds, she is much more likely to get off at the next opportunity.
Yeh, and what happens to the monohull after 45-50 degrees? It starts losing stability. A cruising cat has about 4 times the righting moment than the same size monohull. A gust that may knock the mono over on it's ear would have much less dramatic effect on a cat. A lot of you monohull guys that have no experience in cruising multihills fall into the same misconception. That the windforce that knocks down a monohull has a similar chance of capsizing a multihull. Taking into account that the boats are being properly sailed in the conditions experienced. A 50 foot cat has a righting moment of around 200,000 ft. lbs. At this point it will start to lift a hull. A 50 foot monohull has righting moment around 50,000 ft lbs and at that point it is heeling over at 45-50 degrees. The stability chart I have compares this size boat that why it is 50 feet. We have to take into account the sea state also and as this can vary it is a little harder to quantify. A big factor that contributes to capsize resistance is steering control. A boat that broaches in heavy weather is likely to be rolled over. Multihulls have excellent steering control at speed in large waves. With their high stability and excellent control, conditions that may have a monohull broaching out of control would not seriously trouble a well designed multihull. Racing beach cats does not really give you all that much insight into the seaworthiness of cruising multihulls.

I understand your comparison of the 45ft mono to the 32 ft cat from a dollar perspective and it may have some merit. But from a strictly size argument it is no more valid than comparing the seaworthiness of two monohulls of 45 and 32 ft.
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Old 05-04-2008, 15:06   #35
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Sorry, Microsoft sent that out before I got finished...

As I was saying, you are out there one your own, and you don't want to expose anyone to danger having to save you, even if they could.

You can do a circumnavigation and avoid a high PF most of the time, but occasionally the odds will catch up with you and you will be in survival conditions. What happens next is up to you and your boat. If you have a large and experienced crew, you can avoid disaster most of the time by ACTIVE management of the boat. However, most circumnavigations are taken by couples, where one partner is less experienced, more apprehensive, and less skilled at sailing.

It is an inarguable fact that catamarans are more likely to capsize than monohulls-- For at least the first 30-40 degrees of heeling, the more a monohull heels over, the greater the righting moment is, whereas the cat is exactly the opposite. I discovered the reality of this the first year I raced cats--if one hull starts to lift and you don't dump the sheet, you are likely to go over, and stay over. The same thing applies to burying a lee bow. No matter what the salesman tells you, these principles apply to cruising cats when things get hairy, as much from wave action as from wind forces. It is also a fact that, all other things equal, bigger boats are more comfortable and safer when things get rough, and out of control, and you are on the edge.

Now consider your choices--for $150,000 you can buy a 45 ft monohull or a 32 ft cat. When things get close to going out of control out there, your PF is going to be a lot higher on the cat, This translates to higher stress for you, which your partner picks up on. Even if your luck holds, she is much more likely to get off at the next opportunity.
What a load of absolute tripe. It's been proven time and again that cats have survived severe storms with NO ACTION from the crew. In fact cats have survived severe storms with NO CREW to actively manage them.

Your so called "inarguable fact" is an inarguable fallacy - in similar sized boats catamarans will usually have around FOUR TIMES the maximum righting moment of a monohull. That is, it would take FOUR TIMES as much force to capsize them. Which in real terms means they are much more than 4 times LESS likely to ever be capsized.

How do you account for the fact that some cats - Prouts for example - have done over a hundred circumnavigations and none has EVER capsized?

Read the accounts of the Queens birthday storm - several monohulls were rolled repeatedly, and dismasted, and one sank with her crew - the multihulls never capsized, and never lost their rigs.

Once again someone is unable to differentiate between what happened when they raced a hobie back in the '70's to a modern cruising multihull.
That's like saying this: proves that every monohull wil break up and sink whenever the wind exceeds 15 knots. It's absolute rubbish.
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Old 05-04-2008, 17:33   #36
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A multihuller's perspective:

" Multihulls are wonderful boats but they demand our respect. There is no place for the arrogance of superiority. The flat reality is that we have had three capsizes on the Great Lakes in just over a year, and all could have been prevented. "
From Ron Buzil


The perspective of a Prout owner:

"Most terifying of all was the initial flexing of our Prout Escale - joints between walls and bulkheads opened and closed, windows cracked, and hull connections busted as the two hulls went in their respective directions....
So what do you do when you're halfway across the Pacific and the two front windows go because the storm you're in makes the boat flex? Call Canvey Island? Furthermore, even IF Prout Catamarans agrees to replace the acrylic windows, they are only treating the symptom, not the problem (the hull flexing). Ergo, in the future, you will have the same problem all over again unless your cruiser becomes a house boat in a marina." Structural Issues on our Prout Catamaran - Effects
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Old 05-04-2008, 17:54   #37
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Your point would be? I could go looking for cases of production monohulls having problems - there's certainly no shortage of them - but it would prove nothing, just as your post proves nothing. The fact that a brand new Hanse sank shortly after it's rudder fell off : Marine Casualty Investigation Board doesn't prove all monohulls are dangerous. It doesn't even prove all Hanse yachts are. It just means that in an individual instance something went wrong.

Does this: Beneteau First 235 - Rudder - Transom joint prove that ALL beneteau boats are unseaworthy?

Or this? :Are you Serious?: Is this the summer of sinking...??
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Old 05-04-2008, 18:14   #38
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What about capsizing?
Most people who have never experienced a cruising multihull get their fears of capsizing from watching those little Hobie Cats zipping along the beach on one hull. Eventually (inevitably?) the sailor loses control and over it goes.
A cruising cat is much different. The power-to-weight ratio is much lower than its smaller Hobie counterparts. For instance, an Elan 7.7 carries only 310 feet of sail on a boat that weighs 1300 pounds and is over 19' wide. This is a lot different from a beach cat that may have 400 feet of sail on a 400 pound boat that is only 8' wide.
The same comparison can be made on monohulls. Sailing dinghies such as Sunfish and Lasers have a very high sail to weight ratio and often capsize. Whereas on a cruising size keel boat that ratio, once again, is much lower.
Most multihulls will not capsize even under intense conditions. But, if the unlikely should occur "Stay with the boat!" Multihulls don't have ballasted keels and most have additional flotation built in so they stay afloat. A capsized and "holed" monohull will sink like a rock. However, you can have comfort in the fact that it will hit the bottom with the mast pointing up.

Taken from BoatSAFE: Sailing - Monohulls vs Multihulls

I think most people are intelligent enough to form their own opinions. Some will never change their opinions even with the right information they will always find the very few instances that support their outdated beliefs.
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Old 05-04-2008, 18:38   #39
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Sorry guys, go back and look at those stability curves again. What they show is that the cat is rapidly losing righting moment after it heels more than 10 degrees. If you get hit with a micro-burst while you are asleep and your wife doesn't immediately dump the sheets, you are going OVER. The monohull curves Multihull Design Considerations for Seaworthiness show that in the same blast a typical monohull will have an incresing righting moment up to 60 degrees of heel.

A sudden gust is not the only way to flip a multihull--a short cross sea will heel the boat to dangerous angles, breaking waves will do the job, and there's the pitchpole, which accounted for about half of my multihull capsizes.

Now lets look at the consequences when the freak wave and/or wind with your name on it hits. In your cat, you are upside down and helpless. Hope someone comes to your aid. In your monohull, you may take a knockdown, or even a 360 roll, even lose the rig, but the odds are you will soon be back right side up, ready to clean up, repair jury rig, and move on.

Life is not a sure thing--last year a cat flipped near Bermuda with loss of the skipper. In a storm later in the year, a larger monohull was lost with all hands in the same area. However, given the physics of monohulls vs cats, I would much rather be in a monohull when Davey Jones comes calling, especially if I can buy a larger monohull with the same cruising kitty.
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Old 05-04-2008, 18:51   #40
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Yes a mono's stability rises as it heels, (up to a point). We all know that. The thing is tha the righting moment of a mono, even at it's maximum, never goes close to that of an equivalent cat. Usually it's around 1/4. Which means that it will take 4 times as much force to tip the cat over.

Monohulls don't always self right either. Sometimes they stay upside-down. Sometimes they sink before they self right.

And if you get hit by a micro-burst while asleep on a mono, you might just go down with it as it downfloods through the open companionway your wife didn't manage to close in time.( I'd argue that it's quicker and easier to release a sheet than put the boards back into the companionway)

It's easy to waffle on with bullshit like that - the fact is, hundreds of multihulls have circumnavigated safely. They have survived intact through storms that sank mono's. The first ocean crossings ever were made on multihulls.

A monohull may be your preference - in that case go for it. But don't try to say multihulls aren't seaworthy - the facts are against you.
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Old 05-04-2008, 19:05   #41
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The ability of the crew on watch is a good point. In Chris White's "The Cruising Multihull" he cites a study done by the US Navy into how rolling motion debilitates crew. Surprisingly, it seemed that at low levels of roll - up to 5', the performance of crew actually increased. But beyond 10' of roll crew performance suffered dramatically.

So it could be argued that a multihull, with its lower levels of roll, could result in a crew better able to help itself in survival conditions.
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Old 05-04-2008, 19:49   #42
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"Also, smaller cats are more susceptible to loss of
performance due to 'overloading'. You will load up a cruising boat and
cats carry less than the equivalent sized mono)."

I dont know, this may be a common misconception, I moved directly froma Passport 47 to a Lagoon 42 cat. We had way to much stuff... The passport was down 5" on the water line, the cat went down maybe 3" !

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Old 05-04-2008, 20:26   #43
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Sorry guys, go back and look at those stability curves again. .
Hmmm, anyone else see what happens to a Beneteau in real seas? They flex so much cabinet doors are never the same. Can someone point me to the Beneteau circumnavigation thread?

Yes, I know, not a kind remark. But neither is knocking a boat you've never sailed on and that's the only point I'd like to make here.

Don't knock it unless you've been out there on a catamaran.
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Old 05-04-2008, 20:40   #44
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Can a Lagoon 38 or 42/43, Prout 37 or similiar cross oceans "no problem"? Can they actually handle heavy seas, waves, and weather? Could a smaller PDQ 32?

Jeff

A very simple answer: Mine did. I just bought it, but it's 34', was built in England and is now in the USA after extensive traveling (Yucatan, Windward islands, Trans Atlantic etc...)

Also, the guy from the post above me's cat was sailed on its own bottom from England as well (same manufacturer).
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Old 05-04-2008, 20:42   #45
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What an absolute waste of bandwidth.
We could go on forever with examples supporting either extreme view such as the bendytoys keels falling off or monos that hit something and holeing the hull whereas a cat can have collision bulkheads to prevent the sinking. etc etc yadda yadda ad infiniteum.

I thought Cruisers was a MULTIHULL forum- Where do all these monohullers keep coming from.


Mike

Edit. I just had a look and there is an area for the monohullers. Fancy that I never noticed before.
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