Catamarans in 50kt winds

[beiland]

Originally Posted by Dockhead

...
Getting back to the original topic -- if you get caught out in a sudden, violent squall with too much sail up, in a mono, it is extremely unlikely that anything will happen to you worse than a broach or a partial knock-down. That's because your sails are depowered as the boat heels, and then the righting moment of the keel pulls you back upright. It's theoretically more dangerous in a cat since these factors are lacking, but in practice, cases of cats being blown over by wind alone are exceptionally rare, and not something I would worry about. For both cats and monos, the dangerous thing is the sea state, not the wind.

There was a study done by Lock Crowther years ago at the Southampton Univ test tank....

Note: reference source, Lock Crowther Designs

"This work (tank testing at Southampton Univ) has indicated that the well designed catamaran is remarkably safe in breaking waves up to considerable height, even when beam on, we were unable to capsize a power catamaran yacht in the largest wave which could be generated. This corresponded to a 52' wave for a catamaran of 40' beam. Scaling this down to a typical 24' beam cruising cat means she should be O.K. in a 31' breaking beam sea. An equivalent size mono-hull power boat was easily capsized by a 25' breaking sea, and in tests with conventional yachts after the Fastnet disaster, it was found that a 40' mono-hull yacht could capsized in a 12' breaking sea"


Beamy cats are better survivors
Catamarans and Waves | Multihull Design Blog

[Mr B]

Originally Posted by Simonsays

just throwing this in here, to remind y'all what you are talking about (or not)

What sailing vessel has the power to sail or motor into that,
You will find most sailing boats will be running before it,
Running in front of an ocean like that, Flattens it out a lot,
I dont have any problems with an ocean like that, Tiny bit of Genoa is all thats needed,
I have no idea on how a Mono would handle running in front of it, Whether it would get a beating or not,
Or a nice easy ride like the Cats get,

[Dockhead]

Originally Posted by beiland

There was a study done by Lock Crowther years ago at the Southampton Univ test tank....

Note: reference source, Lock Crowther Designs

"This work (tank testing at Southampton Univ) has indicated that the well designed catamaran is remarkably safe in breaking waves up to considerable height, even when beam on, we were unable to capsize a power catamaran yacht in the largest wave which could be generated. This corresponded to a 52' wave for a catamaran of 40' beam. Scaling this down to a typical 24' beam cruising cat means she should be O.K. in a 31' breaking beam sea. An equivalent size mono-hull power boat was easily capsized by a 25' breaking sea, and in tests with conventional yachts after the Fastnet disaster, it was found that a 40' mono-hull yacht could capsized in a 12' breaking sea"


Beamy cats are better survivors
Catamarans and Waves | Multihull Design Blog

That study dealt with power cats, which lack a rig and have a lower center of gravity, so not directly comparable with sailing cats. However, I think it's pretty clear that catamarans, having more beam per a given amount of hull volume (not to speak of length), are more resistant to capsize.

However, keep in mind that the consequences of a capsize are worse in a catamaran, since you won't come back up. Whereas in a mono, you pop back up.

But in any case, as I and others have said a few times by now in this thread, there is no evidence that catamarans are more dangerous, in big sea conditions, than monos, particularly larger cats. I think quite clearly, they are not.

[Cottontop]

Originally Posted by beiland

There was a study done by Lock Crowther years ago at the Southampton Univ test tank....

Note: reference source, Lock Crowther Designs

"This work (tank testing at Southampton Univ) has indicated that the well designed catamaran is remarkably safe in breaking waves up to considerable height, even when beam on, we were unable to capsize a power catamaran yacht in the largest wave which could be generated. This corresponded to a 52' wave for a catamaran of 40' beam. Scaling this down to a typical 24' beam cruising cat means she should be O.K. in a 31' breaking beam sea. An equivalent size mono-hull power boat was easily capsized by a 25' breaking sea, and in tests with conventional yachts after the Fastnet disaster, it was found that a 40' mono-hull yacht could capsized in a 12' breaking sea"


Beamy cats are better survivors
Catamarans and Waves | Multihull Design Blog

Somewhere I read that a cat won't flip from wave action in a beam sea until the height of the wave exceeds the beam of the cat; that is, until the entire cat is "on" the face of the wave. Somehow that has intuitive appeal to me, but my intuition has let me done many times.

[valhalla360]

Originally Posted by El Pinguino

Really? I didn't know that........

You learn something new every day. At least that's the explanation, I've heard from a number of sources.

The idea that they are warmer doesn't make a lot of sense when you figure the coring in catamarans is effectively very good insulation. Not so good shrugging off large chunks of ice but good for insulation.

[Simonsays]

Originally Posted by Mr B

What sailing vessel has the power to sail or motor into that,
You will find most sailing boats will be running before it,
Running in front of an ocean like that, Flattens it out a lot,
I dont have any problems with an ocean like that, Tiny bit of Genoa is all thats needed,
I have no idea on how a Mono would handle running in front of it, Whether it would get a beating or not,
Or a nice easy ride like the Cats get,

for yarn like that you should at least bring a bottle of rum to wash it down with.

[valhalla360]

Originally Posted by El Pinguino

Fit wheels, sail on top of ice..... try that on a mono...

I think this thread has gone that far off topic that the OP has long since left the bullding.

Actually, I saw a design for a high arctic cruising cat a while ago. No idea if they built it but it had effectively a long steel runner along the bottom of the minikeels and the leading edge had a very shallow slope. The idea was if you got stuck in ice, an extra heavy duty anchor winch would pull you up onto the ice and you would be an ice boat skating along the surface.

[SVNeko]

Originally Posted by valhalla360

Actually, I saw a design for a high arctic cruising cat a while ago. No idea if they built it but it had effectively a long steel runner along the bottom of the minikeels and the leading edge had a very shallow slope. The idea was if you got stuck in ice, an extra heavy duty anchor winch would pull you up onto the ice and you would be an ice boat skating along the surface.

Garcia is showing an aluminum cat billed for exploration ... Indeed, called Explocat. Bloody heavy thing, though.


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[Mr B]

Originally Posted by Simonsays

for yarn like that you should at least bring a bottle of rum to wash it down with.

At least you will be safe in your arm chair,

[smj]

Originally Posted by Dockhead

That study dealt with power cats, which lack a rig and have a lower center of gravity, so not directly comparable with sailing cats. However, I think it's pretty clear that catamarans, having more beam per a given amount of hull volume (not to speak of length), are more resistant to capsize.

However, keep in mind that the consequences of a capsize are worse in a catamaran, since you won't come back up. Whereas in a mono, you pop back up.

But in any case, as I and others have said a few times by now in this thread, there is no evidence that catamarans are more dangerous, in big sea conditions, than monos, particularly larger cats. I think quite clearly, they are not.

As has been said before, a monohull isn't guaranteed to pop back up. I'm sure it has a much better chance of popping back up than sinking but not a 100% chance. After the 360 degree roll, I'm sure it would be time for a little spring cleaning :-)


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[Simonsays]

Originally Posted by Mr B

At least you will be safe in your arm chair,

no Sir, you stay safe, if you really think what you said there.
i'll be at the Hamburg Summer Classics this weekend, without F10 winds.
and it's not an arm chair, i worked for my CPL in the Navy.

[Dockhead]

Originally Posted by smj

As has been said before, a monohull isn't guaranteed to pop back up. I'm sure it has a much better chance of popping back up than sinking but not a 100% chance. After the 360 degree roll, I'm sure it would be time for a little spring cleaning :-)

Being rolled by a large breaking sea is a disaster which usually results in the rig being torn off. Rolled monohulls don't usually sink, but sometimes do -- mostly from holes being ripped in the hull when the rig is torn off.

Certainly no picnic, but the boat may be habitable and might be navigable with jury rig or engine afterwards, which of course is a big plus.


I have been knocked down by a large breaking sea, and that's no picnic, either. My boat popped back up and I suffered no damage, but I reckon
I was lucky. The size of my boat and conservative stability curve might have saved me. A smaller mono might have been rolled by the same event, and a smaller cat might have been flipped.

[GoingWalkabout]

Originally Posted by smj

As has been said before, a monohull isn't guaranteed to pop back up. I'm sure it has a much better chance of popping back up than sinking but not a 100% chance. After the 360 degree roll, I'm sure it would be time for a little spring cleaning :-)


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It used to be common for low latitude monohull sailors to wear crash bicycle helmets. Broken bones and head injuries from knock downs are par for the course in monohull big sea adventures. By the way. I don't know why some think it is appropriate to talk about racing cats flipping when on a cruisers forum. There just is not relationship between a racing cat and cruising cat especially when it comes to stability.

Anyway. I like the old scout motto. "Be Prepared" Wether your in a cat or a monohull it is being prepared and acting wisely that is the most important. For me I would rather be throwing out a drogue and sailing bare poles or with very little sheet sitting and having a warm coffee in the salon than siting bellow in a monohull being donning my crash helmet and being thrown around like a rag dole in the mouth of a pit bull.

But what do I know. I'm still looking for my ideal cruising cat and I make no pretense at being an expert. But I am a good student and a good learner. And I do have common sense. Something that seems to be surely lacking in some of these posts by some of the (not all, only some) ignorant mono sailors.

i have read extensively. Spoken to seasoned cat owners. And yes even seen cats on video in high seas. I hare learned a great deal from sinking, knock down and capsizing reports. By the way it is better to learn from others mistakes than having to learn them from your own experience. So some may say I have no right to make a comment on this issue. That by the way is usually the position taken by those who can't defend their positions or beliefs and are threatened by lets say a more intelligent approach to making decisions.

Experienced sailors I hold in the very highest of regard. Don't get me wrong there is nothing like real life experience to inform ones education.

But for me when I go and put down my hard earned dollars on my next sailing boat it will be done after coming to my own conclusion of what is safe, seaworthy and good for me.

In the meantime I will continue to learn and take in the advise of the wonderful sailors on this forum and always keep an open mind. But I will also disregard the nonsense that some so called old sea salts dish out based on ignorance and plain stupidity. The ones who lack the sense to research and learn from others in an intelligent and disciplined way.

To all the seasoned sailors that I have already leaned so much from on this forum I say thank you. To the ignorant prejudiced blow hards I say, I am sure you all would be a good source of whopper stories over a bear in a port.

Regards,
Chaya

[weavis]

Originally Posted by GoingWalkabout

To all the seasoned sailors that I have already leaned so much from on this forum I say thank you. To the ignorant prejudiced blow hards I say, I am sure you all would be a good source of whopper stories over a bear in a port.

Regards,
Chaya

I can honestly say I have never heard whopper stories over a bear in a port.. or anywhere for that matter....

[donradcliffe]

Originally Posted by KJThomas

Just lost yours. I was boatbuilding in Whangarei for 15 years until 2009. We never had less than 20 multihull cruisers on the hard each summer. Increasing constantly up until now. Then of course Opua, Auckland and all those on the coast. Then there is all the rest of the South Pacific. Including the cats domiciled in French Polynesia, New Zealand and Australia.
This year we had about 1/3 cats to monohulls. 7 crossed the Tasman from Oz.

If there were 20 cruising Multi's in Whangarei when I was there in 1992 they were well hidden.

Thanks for jogging my memory, though. I DID see a 32 ft catamaran in Penhryn in 1992. It was on the beach, with holes in both hulls because its owner had run it into one of the bommies in the lagoon. I went over to give him a hand, but he didn't want my help. The locals told me that he damaged it on purpose. He had single-handed from Tahiti because his crew had left him. He didn't think he could complete his voyage to South Africa in that boat, so he was trying to do an insurance job.

When I returned to Penhryn in 1997, I asked what had become of the cat. The story was that the insurance company called his bluff, sent a surveyor, and refused to total the boat. They loaded it onto the inter-island freighter (big event in Penhryn, and I saw the pictures) and shipped it to NZ for repair. It is probably still in storage in Whangarei.

Apologies for the thread drift, but this thread has long since ended its useful life.