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Old 04-04-2016, 12:43   #106
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Re: Reasons to stay "Monohull"

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Originally Posted by Kim Klaka View Post
Thanks for the kind words. Before commenting on the stability matter, I add two points about objectivity:
1. Buying a boat isn't a purely objective process. As has been stated earlier in this thread, you (one) tend to choose your boat then try and justify it after.
2. Aesthetics does play a big part. i couldn't bring myself to buy an ugly boat, no matter how well it met my technical criteria.

So, onto the capsize v sink issue. i don't know how many monos have survived a full 180 roll, but there are many. Some monos sink after a capsize/rollover, others do not, it depends not only on the design but also the environment and the way the boat has been operated ( e.g. if the seacocks are open when the boat is inverted, air can escape and the boat is more likely to sink). i think we ned to look further than the capsize likelihood. Risk is about both likelihood and consequence, so the debate should extend to the suitability of the boat for survival once the catastrophe has occurred. Clearly some monohulls will sink, so they are not a suitable platform for survival, but what about those that remain afloat? They have to be fairly stable, yet not be awash with waves. These are two conflicting requirements in terms of hydrostatics, requiring careful design to obtain a satisfactory compromise. If a mono is fairly stable once it pops upright, and isn't awash, then it is a suitable platform. If it is awash, then it is dangerous. Many people criticised the crews who abandoned their boats in the 1979 Fastnet race because their boats were subsequently found afloat, thus "proving" they had made the wrong decision. What got lost in the noise was the clarifying statement from some of those crew, that it was too dangerous to stay on board the awash boat - they were getting seriously injured from being thrown around.
If the mono does not right itself, it can still be a survival platform, but it is less than wonderful (e.g. the Tony Bullimore Southern Ocean episode c 1996)
So the monohull can be a suitable platform for survival, but not all that often.
Multihulls rarely sink after capsize (but it has happened), and there are things you can do to make them habitable when inverted. however, they are purely a survival platform where you sit and wait rescue, whereas a righted mono has a modest chance of setting a jury rig and getting to a harbour of refuge (e.g. Tzu Hang)
so the multi is usually a better survival platform than the mono, but cannot get itself to safety. It is also (arguably) a bit more likely to capsize and a lot more likely to stay capsized.
When you put all these factors together, the question " which is better, mono or multi?" becomes rather meaningless, as it depends so much on the boat, the crew, and the environment. And that's why there are both monos and multis used for sailing the oceans successfully. Unless of course all the above is a smokescreen put up by naval architects in order to keep themselves employed :-)
Kim Klaka MRINA
Statistically there is no difference between the safety of cats vs monos.


I always felt uncomfortable, and even frightened sailing a catamaran in strong conditions, because you can't feel when you're getting overpowered. It feels like you might flip!

But I think that this is a question of familiarity. I imagine you get used to it, and learn to read different clues, than what we use on monos.
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Old 04-04-2016, 12:43   #107
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Re: Reasons to stay "Monohull"

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On the European Atlantic coasts, at least, catamarans are so rare as to be exotic. They are rarer than Open 60's for sure....
I guess a good indicator regarding Europe and the ones that are used for extensive cruising is the percentage on the ARC. A small percentage, maybe 10% or so but even so one that is increasing slowly.

Or maybe not a good indicator because I have been told that many cats that do the ARC are charter boats heading for the Caribbean and that they got an extra money doing charter during the ARC, accepting guests, a more and more popular charter program these days.
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Old 04-04-2016, 12:58   #108
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Re: Reasons to stay "Monohull"

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Originally Posted by Lizzy Belle View Post
(We used to be one of the few marinas that simply charged by length x width, which was a fair system for cats too. Which is why we had 2.)

I looked at a few marinas in Belgium, and they all charged on a length x width base, which is indeed a fair system.


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Old 04-04-2016, 14:21   #109
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Re: Reasons to stay "Monohull"

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How does the caps ratio fit into capsizing. Mow can you compare a mono with a ratio of greater than 1 to a cat?


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Sailor Doug: maybe if you expand on your idea the matter can be addressed in more detail.

Otherwise capsize ratio calculated for monohull boats does not apply to multihull boats. For the base for the calculations is one hull.

What caps ratio are you talking about then?

If you talk about CSF then as far as I remember the lower values are better and values of less than 2 are desirable in offshore boats. Monohulls.

Multihull boats are initially very stiff and their GZ peaks 'sooner'. Vide image.

http://www.shuttleworthdesign.com/img/NESF3.GIF

Cheers,
sailor barnakiel
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Old 04-04-2016, 14:40   #110
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Re: Reasons to stay "Monohull"

I was referring to the one in my Europe documentation. My point was that some monos have higher resistance to capsizing.
Never sailed a cat but would like to. I looked at them before buying my boat. I felt the interior hulls were too narrow at my price point.


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Old 04-04-2016, 14:56   #111
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Re: Reasons to stay "Monohull"

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I guess a good indicator regarding Europe and the ones that are used for extensive cruising is the percentage on the ARC. A small percentage, maybe 10% or so but even so one that is increasing slowly.

Or maybe not a good indicator because I have been told that many cats that do the ARC are charter boats heading for the Caribbean and that they got an extra money doing charter during the ARC, accepting guests, a more and more popular charter program these days.
I would bet you dollars to doughnuts that no more than 1% of the catamarans doing the ARC ever come back to Europe.

Not just charter boats, but customer boats going to North America.
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Old 04-04-2016, 18:01   #112
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Re: Reasons to stay "Monohull"

One aspect of sail trim in not heavy air upwind.... when the boat is in the grove it will tell you by the heel... even when the sail "looks" ok (assuming no tell tails)...cats don't heel and so the sails aren't telling you as much about their trim because the boat doesn't stand up or heel more... sure speed changes... so you need to be looking at your (inaccurate) fouled speedo reading. Caveat... I have not sailed a cat...
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Old 04-04-2016, 18:20   #113
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Re: Reasons to stay "Monohull"

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I was referring to the one in my Europe documentation. My point was that some monos have higher resistance to capsizing.
...
Europe documentation? what are you talking bout? In Europe nobody uses the capsize ratio that is a very limited tool and only suitable to give some information about boats of a given era (not modern ones).

In Europe what is used to access a boat stability are stability curves. They provide reliable information about a boat stability.
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Old 04-04-2016, 18:33   #114
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Re: Reasons to stay "Monohull"

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Greetings,

I'm asking this here vs a more "vs" question on the cat side of things

I am just starting to actually align my life with long distance sailing/living aboard. Whereas in the past few years I have just been dreaming. I plan to attend sailing schools this year into next. Possibly make the serious move to start the purchasing process later part of next year.

Though I have no sailing-by-wind experience, I have been to sea many times and for very long periods. Also I own a mechanical/heavy fabrication business which affords me knowledge in mechanical systems, and the ability to easily learn marine applications.

So my question: what keeps the monohull market so plentiful when you hear all the good "benefits" of catamaran sailing? It seems like everyone would want a cat vs a monohull based on the rants I read? With cost subtracted from the equation please (I do not yet know the extent of my budget), why do you stay monohull?

Thank you so much

Regards,

Adam J
It's very much a personal choice. For my wife and I a monohull is for us.

There is no one size fits all. Boats aint airline security lines. (We're all forced to endure the same crap there)

The benefits are numerous but I would choice a cat over a monohull if:

1) I wanted a party boat with lots of room to host lots of people on board (i don't)
2) my wife didn't like healing (she does and she is the sailor in our family having completed 2 sydney to hobarts and 11 years defence sailing)

It's your choice.

Charter both monohulls and cats. You'll quickly realize which is for you.

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Old 04-04-2016, 18:40   #115
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Re: Reasons to stay "Monohull"

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Europe documentation? what are you talking bout? In Europe nobody uses the capsize ratio that is a very limited tool and only suitable to give some information about boats of a given era (not modern ones).

In Europe what is used to access a boat stability are stability curves. They provide reliable information about a boat stability.

Have you never heard of CE class A certification??


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Old 04-04-2016, 18:42   #116
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Re: Reasons to stay "Monohull"

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Have you never heard of CE class A certification??


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That's the one the builders came up with
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Old 04-04-2016, 19:02   #117
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Re: Reasons to stay "Monohull"

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That's the one the builders came up with

I thought it was the bureaucrats in Brussels.


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Old 04-04-2016, 19:42   #118
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Re: Reasons to stay "Monohull"

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Have you never heard of CE class A certification??
Certainly but as I said they don't use capsize ratio but stability curves and a STIX number that has nothing to do with capsize ratio.
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Old 04-04-2016, 19:46   #119
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Re: Reasons to stay "Monohull"

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I thought it was the bureaucrats in Brussels.


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I think not, it may be administered there but the original documents were put together by the builders when they agreed the minimum standards they could live with. Designers acting on behalf of the builders had imput as well.
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Old 04-04-2016, 19:46   #120
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Re: Reasons to stay "Monohull"

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I thought it was the bureaucrats in Brussels.
..
You are right on that one, it has nothing to do with the builders, it pisses the builders and it was not made (and actualized) by bureaucrats but by a technical committee of NA and NE after an extensive debate by a huge number of NA all over Europe and even with the participation of some American ones.
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