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Old 26-12-2014, 14:41   #136
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Re: Capsized Atlantic 57 Salvaged

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Originally Posted by 44'cruisingcat View Post
I'll be honest here: I have absolutely no idea what you're trying to say.
So you really let go the traveler when a cat lift a hull and menaces capsizing instead of letting go the mainsheet. Interesting
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Old 26-12-2014, 15:06   #137
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Re: Capsized Atlantic 57 Salvaged

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Originally Posted by 44'cruisingcat View Post
Polux answered your question incorrectly though. The correct answer is: it depends.

If a cat and a tri were the same beam, and the same weight, they'd have the same righting moment. Even though, as you said, half of the cat's weight is in the "pivot" hull. Because the other half is right out at the other end, not in the middle like on a tri.

Both boats' CG would be in the middle. Same beam, same CG location, same weight = same righting moment.

The tri will be harder to capsize only if it is wider.
Wrong and wrong. Yes on a well balanced boat the CG will be on the center of the boat but you forget that most cats, like yours, have a deck house on top of the hulls while on modern designed trimarans the accommodations are low inside the center hull. This obviously lowers the CG.

It can be on the same center line but the CG it is lower and that will increase stability. Having both boats (trimaran and catamaran) the same beam and weight, the one with the lower center of gravity will be the one with more stability.

Regarding beam on cats and trimarans, the two modern cruising trimarans that sell more are the Corsair and the Dragonfly. Do you mind to post a cruising cat with the same Length Beam ratio? I don't know any.

In what concerns answering the question (compared stability between a trimaran and a catamaran), even if some things are obvious, I don't like to take the credit from anybody and this typical stability curve comparing the stability of a 35ft trimaran with the stability of a 35ft catamaran is not mine but from a NA specialized on Multihull designs.
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Old 26-12-2014, 15:28   #138
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Re: Capsized Atlantic 57 Salvaged

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Originally Posted by yeloya View Post
Just two points; the ARC results that some forumers are refering to are completely irrelevant. This is all the way downwind (althought some years was not), motoring is free and more importantly everybody has a different mood of doing it. Being on the right spot on the right time to catch the best wind also plays a mojor role. In short, it doesn't say anything about the performance of the boat..
Some people are still discussing the potential speed of mono vs. catamarans. Apple to apple, the cat will always win to any wind direction. I had a chat with the skipper of Gunboat 62 when they visited our yard, his statement was clear: "we were never ever overtaken in any race by any mono which is shorter than us, including Volvo 60.." He said that they raced in some of the Caribeean regattas which consist of rounding the island,hence, sailing to any direction, not only down wind..

Cheers

Yeloya
I don't agree. When you have 300 boats to compare you have average results that can and are meaningful besides on the ARC they post the litters of Diesel each boat used and between fast cats and fast monohuls they are not significant (both use none or very little). In what regards the others the numbers are very similar and normally cruising cats have a bigger tankage than cruising monos.

Regarding the Gunboat 62 that made the 2013 ARC, that is a boat that is used for racing, with a racing skipper and at least some pro sailors, the facts are these, take your conclusions, but they seem clear to me (posted on another forum):

"A Knierim 65, a monohull performance cruiser of about the same size beat the Gunfleet 62 by almost 5days!!!

In 2013 the performance of the Gunfleet 62 (or the other cats) did not appear to me nothing special. Regarding cats I was more impressed by the performance of a Lagoon 560, a much slower and smaller condocat that made in my opinion a much more remarkable passage, doing it on only more 2 days and 5 hours.

If we compare the almost 5 days that the Gunfleet 62 lost to the to the Knierim 65 with the 2 days 5 hours that the Lagoon 56 lost to the Gunfleet or even with the 10 hours that the much smaller performance cruiser Marten 49 lost for the Gunfleet, it is not with the Gunfleet performance that I am impressed with.
...
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Old 26-12-2014, 15:30   #139
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Re: Capsized Atlantic 57 Salvaged

Well thanks wherever the explanations are coming from. That the tri has a lower center of gravity makes sense, thus making it less tippy. Maybe that is the entire explanation for the difference in the stability graph. The outer hulls of the tri and cat are different of course, which may make a difference.
But what the heck do I know. I just know I am going multi (or a maxi) for my next boat.
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Old 26-12-2014, 15:35   #140
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Re: Capsized Atlantic 57 Salvaged

Quote:
Originally Posted by Polux View Post
I don't agree. When you have 300 boats to compare you have average results that can and are meaningful besides on the ARC they post the litters of Diesel each boat used and between fast cats and fast monohuls they are not significant (both use none or very little). In what regards the others the numbers are very similar and normally cruising cats have a bigger tankage than cruising monos.

Regarding the Gunboat 62 that made the 2013 ARC, that is a boat that is used for racing, with a racing skipper and at least some pro sailors, the facts are these, take your conclusions, but they seem clear to me (posted on another forum):

"A Knierim 65, a monohull performance cruiser of about the same size beat the Gunfleet 62 by almost 5days!!!

In 2013 the performance of the Gunfleet 62 (or the other cats) did not appear to me nothing special. Regarding cats I was more impressed by the performance of a Lagoon 560, a much slower and smaller condocat that made in my opinion a much more remarkable passage, doing it on only more 2 days and 5 hours.

If we compare the almost 5 days that the Gunfleet 62 lost to the to the Knierim 65 with the 2 days 5 hours that the Lagoon 56 lost to the Gunfleet or even with the 10 hours that the much smaller performance cruiser Marten 49 lost for the Gunfleet, it is not with the Gunfleet performance that I am impressed with.
...

The Gunfleet is a mono, while the Gunboat is a multihull.


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Old 26-12-2014, 15:49   #141
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Re: Capsized Atlantic 57 Salvaged

interesting post ,
some one asked if cats when they lift a hull keep going or just sort of hang there .my experience is that most come out slowly and can be easily controled this was was the case on Our PDQ 27 (home built sport cat )and on our PDQ 36 .On the 36 it has been rare and really more of the weather hull just kissing .However on the 27 it was full on with the rule of thumb being if the rudder tip comes out ease the traveller .
The only cat that I ever saw have rouble controlling the lift was a Macgregor 36 .It would stay flat and them bamm up it would go like a rocket and all the sheets had to be dumped .It had a very shallow dead rise an a deep transom .I always thought that there was (for the lack of a better word) a moment of suction that need to be broken due to the hull shape .
We also raced against a G32 .That boat was very fast except in light winds .With water ballast and only 8 feet wide and had a mast head float that doubled as a large windex it was more like sailing a mono in some ways .the beauty of the design was that it lifted with so little wind in comparison to a normal sport cat ,that its wetted surface went to nothing . As for the mast head float in one race with the wind at about 15 he was so far ahead of me that he capsized and righted and I did not know until afterwords.
All they had to do was ease the weather shrouds, and as some as the hull got to a certain point it righted it self,reset the sheets and off you go . The Gougeons are smart lads
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Old 26-12-2014, 16:30   #142
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Re: Capsized Atlantic 57 Salvaged

Quote:
Originally Posted by Polux View Post
So you really let go the traveler when a cat lift a hull and menaces capsizing instead of letting go the mainsheet. Interesting
Once again, arguing against things I never said. Please show me where I said anything even resembling that.

If you have to resort to pretending that people have said something which they absolutely have not said, so you can get your jollies arguing against it, then please go away.

I was referring to accidental gybes, and the difference having a wide traveller makes to the severity of it. Never mentioned overpowered boats at all.

When I feel the boat is getting overpowered, and LONG before lifting a hull, yes, I will ease the mainsheet.
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Old 26-12-2014, 16:44   #143
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Re: Capsized Atlantic 57 Salvaged

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Originally Posted by Polux View Post
Wrong and wrong. Yes on a well balanced boat the CG will be on the center of the boat but you forget that most cats, like yours, have a deck house on top of the hulls while on modern designed trimarans the accommodations are low inside the center hull. This obviously lowers the CG.

It can be on the same center line but the CG it is lower and that will increase stability. Having both boats (trimaran and catamaran) the same beam and weight, the one with the lower center of gravity will be the one with more stability.

Regarding beam on cats and trimarans, the two modern cruising trimarans that sell more are the Corsair and the Dragonfly. Do you mind to post a cruising cat with the same Length Beam ratio? I don't know any.

In what concerns answering the question (compared stability between a trimaran and a catamaran), even if some things are obvious, I don't like to take the credit from anybody and this typical stability curve comparing the stability of a 35ft trimaran with the stability of a 35ft catamaran is not mine but from a NA specialized on Multihull designs.

If a trimaran has low buoyancy amas wouldn't they tend to bury and lead to pitchpoling? I think it's a boat to boat comparison not tri to cat comparison.
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Old 26-12-2014, 17:10   #144
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Re: Chris White on the capsize

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Mr White himself has made a statement and the article is quite good:

Chris White Designs
Good article. Even medicine is learning from aviation protocols where there are checklists for nearly every eventuality, routine and emergency.
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Old 26-12-2014, 17:25   #145
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Re: Capsized Atlantic 57 Salvaged

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So you really let go the traveler when a cat lift a hull and menaces capsizing instead of letting go the mainsheet. Interesting
Hmmm. I started sailing and racing cats in 1977 and 1978, respectively. On beach cats, easing the main sheet is the way most skippers manage an impending capsize - unless they are also playing the downhaul and can depower by flattening the main with that. Or, trim in the jib to close off the slot, or all three. Easing the traveler is what those do who come in in the back of the fleet. If you have to ease the traveler, you're getting close to being too late.

On cruising cats, what's a traveler? But for what it's worth, I have never had to ease the main to avoid a capsize. I have eased the main during squalls to slow the boat and to keep from damaging the sail or something else. Capsize was the furthest thing from my mind.

I don't think I could intentionally capsize my boat if I wanted to - unless I was out in conditions that I shouldn't be in. With today's ample availability of weather information, there is no excuse for a competent cruising cat skipper to get caught in conditions where a capsize is possible. JMHO

What cats have you sailed/raced and how do you do it?

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Old 26-12-2014, 17:41   #146
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Re: Capsized Atlantic 57 Salvaged

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Originally Posted by Dave852 View Post
The Gunfleet is a mono, while the Gunboat is a multihull.
Sorry about that. Now it is right. Really it is all about odd name sailing brands, gunboat, gunfleet, very confusing. It seems that I am getting old Now it is right, a Gunfleet is a medium weight boat and as such has a very good performance but not on the playground of a Gunboat, much less on the Knierim or even on the Marten 49

Quote:
Originally Posted by Polux View Post
I don't agree. When you have 300 boats to compare you have average results that can and are meaningful besides on the ARC they post the litters of Diesel each boat used and between fast cats and fast monohuls they are not significant (both use none or very little). In what regards the others the numbers are very similar and normally cruising cats have a bigger tankage than cruising monos.

Regarding the Gunboat 62 that made the 2013 ARC, that is a boat that is used for racing, with a racing skipper and at least some pro sailors, the facts are these, take your conclusions, but they seem clear to me (posted on another forum):

"A Knierim 65, a monohull performance cruiser of about the same size beat the Gunboat 62 by almost 5days!!!

In 2013 the performance of the Gunboat 62 (or the other cats) did not appear to me nothing special. Regarding cats I was more impressed by the performance of a Lagoon 560, a much slower and smaller condocat that made in my opinion a much more remarkable passage, doing it on only more 2 days and 5 hours.

If we compare the almost 5 days that the Gunboat 62 lost to the to the Knierim 65 with the 2 days 5 hours that the Lagoon 56 lost to the Gunboat or even with the 10 hours that the much smaller performance cruiser Marten 49 lost for the Gunboat 62, it is not with the Gunboat performance that I am impressed with.
...
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Old 26-12-2014, 17:46   #147
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Re: Capsized Atlantic 57 Salvaged

Yes, the traveler.

Something monohull sailors (and some cat sailors) don't realize is that on catamaran-rigged boats (3 stays, no backstay) most of the headstay tension comes from the mainsail. You can't put enough shroud tension on to straighten the forestay in a blow, so the headstay is kept straight (and the jib flat) by keeping the mainsheet tight. Slack the mainsheet, the jib becomes more full, drag and heeling increase, and you loose pointing. Typically you will also move the jib leads out at the same time, just a hair. On the other hand, pinching down the slot also depowers the rig, so if the adjustment was for a puff, the jib lead stays and the jib stays tight.

So yes, if the heeling forces is too high, you play the traveler and keep the mainsheet tight. You've got a long traveler and efficient purchase. You also feather into puffs. Yes, you will blow the mainsheet when things get out of hand, but it is not the primary control.


And this should be the same for cruisers ().
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Old 26-12-2014, 18:00   #148
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Re: Capsized Atlantic 57 Salvaged

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Originally Posted by 44'cruisingcat View Post
Once again, arguing against things I never said. Please show me where I said anything even resembling that.

If you have to resort to pretending that people have said something which they absolutely have not said, so you can get your jollies arguing against it, then please go away.

I was referring to accidental gybes, and the difference having a wide traveller makes to the severity of it. Never mentioned overpowered boats at all.

When I feel the boat is getting overpowered, and LONG before lifting a hull, yes, I will ease the mainsheet.
Regarding this :

Quote:
Originally Posted by Polux View Post
Providing you are near it sailing the boat and are not on autopilot while doing something else that is what most cruisers do while sailing.

Do you mean when you are in a limit situation near a capsize you let go the traveller?

When you are really in trouble on a mono or a multihull you don't let the traveler go, you let lose all the sail (and boom). The traveler is useful to maintain the boat under control on guts while sailing, not on a limit situation.

Too much wind on a modern mono, gusting or not, is never a dangerous situation. Frightening can be, for an inexperienced sailor.
You said:

Quote:
Originally Posted by 44'cruisingcat View Post
I'll be honest here: I have absolutely no idea what you're trying to say.
It seem to me that the logic conclusion was that you do not release the mainsheet on critical situations since you were saying previously that "If you'd only sailed a monohull you'd be unlikely to know how much difference the long traveller on a cat makes to this scenario. On a mono it's quite frightening, and potentially dangerous"

If you did not understood what I was saying and if by the fact that a cat has a bigger traveler than a mono you see that as a potential dangerous factor, it seems to me that it can only happen if when in trouble you release not the mainsheet but the traveler.

Well, given that after all you release the mainsheet and not the travel I cannot see how you see a smaller traveler as a potential dangerous shortcut, anyway, if I do not understood I am sorry but it seemed all very confusing.
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Old 26-12-2014, 18:07   #149
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Re: Capsized Atlantic 57 Salvaged

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Originally Posted by thinwater View Post
Yes, the traveler.

Something monohull sailors (and some cat sailors) don't realize is that on catamaran-rigged boats (3 stays, no backstay) most of the headstay tension comes from the mainsail. You can't put enough shroud tension on to straighten the forestay in a blow, so the headstay is kept straight (and the jib flat) by keeping the mainsheet tight. Slack the mainsheet, the jib becomes more full, drag and heeling increase, and you loose pointing. Typically you will also move the jib leads out at the same time, just a hair. On the other hand, pinching down the slot also depowers the rig, so if the adjustment was for a puff, the jib lead stays and the jib stays tight.

So yes, if the heeling forces is too high, you play the traveler and keep the mainsheet tight. You've got a long traveler and efficient purchase. You also feather into puffs. Yes, you will blow the mainsheet when things get out of hand, but it is not the primary control.


And this should be the same for cruisers ().
I think there's a difference in the case of an impending capsize vs optimal sailing on a racing cat. Yes, play the traveler if you can't maintain optimum heel (windward hull just skipping the water) with downhaul, slot adjustment, mast rotation, tiller technique. These tweek adjustments are often not coarse enough to prevent an impending capsize and main sheet easing is the last resort.

On a cruising cat, again, what's a traveler? I don't have one. The other tweeking adjustments are often not available on the fly on a cruiser. Besides, capsizes are not a threat on the vast majority of cruising cats out there.

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Old 26-12-2014, 18:16   #150
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Re: Capsized Atlantic 57 Salvaged

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Yes, the traveler.

...
So yes, if the heeling forces is too high, you play the traveler and keep the mainsheet tight. You've got a long traveler and efficient purchase. You also feather into puffs. Yes, you will blow the mainsheet when things get out of hand, but it is not the primary control.

And this should be the same for cruisers ().
Yes of course, it is the same thing at least in what regards performance monohull cruising boats that have a long traveler: You play with the traveler on the gusts and when the traveler is not enough you let go the mainshet: That's sailing but that was not the point the point was that what has been said was this, and this does not make sense:

"... how much difference the long traveller on a cat ...On a mono it's quite frightening, and potentially dangerous"

If on a critical situation you let go the mainsheet, on a cat or monohull, how can it be potentially dangerous a smaller traveler on a monohull?

Most of the main market cruising boats don't even have a traveller but a system that works directly with the mainsheet, so on a gust you just let go the mainsheet. How can this be more dangerous? Slightly less efficient in what regards sailing, certainly, but more dangerous? Come on
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