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Old 18-05-2015, 03:16   #151
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by ZULU40 View Post
That wont stop you rolling over, it will just mean that if the design remains the same as the design condition, it will recover and right itself. That process can take up to several minutes.

That will not help a crew in the water, or trapped by their lifeline or debris in the cockpit, nor will it save crew below with all manner of missiles flying about the cabin that could be filling with water.

It also wont stop you pitch poling broaching or gybing to capsize because accidents of this nature are usually a calamity of several conditions through tiredness, happen stance, hypothermia and atrocious, even record breaking bad weather.

If you think it is ok to live in a fools paradise it is probably time to consider its even easier to die in one.
Several minutes is better than no minutes. The window of negative stability in modern mono's is around 90 degrees now. some even less at 60.

The fact they come back up saves life's and saves boats. It is not as terminal for the mono craft when inverted and they can be still fit for propose after where as the cat shifts its duty to that of being dedicated as a survival raft. I am not sure in this position they lend selves to the word "survival" much either and those that venture to sea with no life raft have a screw loose in my humble opinion.

I believe that designers and manufacturers could provide a lot more defence and recovery capability for cats but its not going to happen whilst every cat owner is willing to side with the manufacturer and echo their sermon and rely solely on the probabilities of a non event. I personally think this is the fools paradise. In less than 40 foot or even more you would not get me venturing to the fringes of season or geography on what is available now catamaran wise. - I would like more safety and ability to recover please Mr designer.
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Old 18-05-2015, 03:20   #152
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by rob denney View Post
A simple fuse in the sheet activated by a height sensitive float in the water will stop a cat capsizing, or pitch poling.. There is a poorly drawn example at https://au.groups.yahoo.com/neo/groups/harryproa/files

It only works reliably if the sails can be completely eased on any point of sail, under any load, which is not possible with a mainsail on a stayed mast, and may not be quick enough on a jib sheet requiring multiple wraps around a winch.

An unstayed mast is by itself a good capsize preventer. Not only can the sail weathercock regardless of wind direction or strength, but in a strong gust it bends, automatically depowering the top of the sail.

An unstayed ballestron rig is also a good idea as the sheet loads are low and a single sheet release totally depowers the entire rig.

As for righting after a capsize, a harryproa is a good candidate as it only capsizes to 90 degrees where the buoyant mast stops it going any further. Within seconds of the mast hitting the water, the boat rotates so the mast head is pointing up wind. Windage and wave action may right it from here, flotation under the sail or mast would help.

A better option is to cant the mast 10 degrees to leeward and store heavy weights (batteries, water, etc) low down in the windward hull. This would effectively be self righting, and/or uncapsizable due to wind action. Could still pitchpole, but the self righting would happen once the boat was on it's side.

rob
Great post.. Thanks.
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Old 18-05-2015, 03:56   #153
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by paulanthony View Post
Yes, I could easily enter monohull & dead in google... But the thread here is about terminal capsize of a cat and how to prevent or recover with technology. I think modern mono's have a solution to capsize last time I looked called negative stability.
Your presumption that cats are more dangerous is incorrect and unsupported.

Yes, cats can turn turtle in horrid conditions and no there is no practical means to right them without outside help.

Just as monos can turn turtle in horrid conditions and there is no practical means raise them from the bottom.

Since you've clearly made up your mind and are unwilling to listen to logic, I strongly suggest you get a monohull as you will always live in irrational fear on a cat.
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Old 18-05-2015, 04:06   #154
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by rob denney View Post
A simple fuse in the sheet activated by a height sensitive float in the water will stop a cat capsizing, or pitch poling.. There is a poorly drawn example at https://au.groups.yahoo.com/neo/groups/harryproa/files

It only works reliably if the sails can be completely eased on any point of sail, under any load, which is not possible with a mainsail on a stayed mast, and may not be quick enough on a jib sheet requiring multiple wraps around a winch.

An unstayed mast is by itself a good capsize preventer. Not only can the sail weathercock regardless of wind direction or strength, but in a strong gust it bends, automatically depowering the top of the sail.

An unstayed ballestron rig is also a good idea as the sheet loads are low and a single sheet release totally depowers the entire rig.

As for righting after a capsize, a harryproa is a good candidate as it only capsizes to 90 degrees where the buoyant mast stops it going any further. Within seconds of the mast hitting the water, the boat rotates so the mast head is pointing up wind. Windage and wave action may right it from here, flotation under the sail or mast would help.

A better option is to cant the mast 10 degrees to leeward and store heavy weights (batteries, water, etc) low down in the windward hull. This would effectively be self righting, and/or uncapsizable due to wind action. Could still pitchpole, but the self righting would happen once the boat was on it's side.

rob
This is really clever design. Breaking the mould of the conventional cat. Yeh, I can see how it can be induced to come back up. Layout is brilliant also and on the later design the steering wheel pivots so it can be used in the saloon. Brill! Have not seen before so thanks for the heads up.
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Old 18-05-2015, 04:13   #155
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Re: Is there a catamaran of cruising size that can self right unaided?

here's a video of a cruising cat coming through the southport seaway in australia. slightly off topic but interesting footage to say the least

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Old 18-05-2015, 04:54   #156
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Re: Is there a catamaran of cruising size that can self right unaided?

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Your presumption that cats are more dangerous is incorrect and unsupported.

Yes, cats can turn turtle in horrid conditions and no there is no practical means to right them without outside help.

Just as monos can turn turtle in horrid conditions and there is no practical means raise them from the bottom.

Since you've clearly made up your mind and are unwilling to listen to logic, I strongly suggest you get a monohull as you will always live in irrational fear on a cat.
Well, now you have started to enter into reasoned dialogue(thank you) I will start to listen.

The issue I have presented here is not one which tries to consider holistically that which is more safe, i.e. two hulls versus a single displacement one but the dynamic of capsize itself. In this respect the conclusion of capsize for a cat is generally fatal.

The overall flaw of a cat is that it is contemptuous of nature. Its design philosophy is to resist rolling with all eggs given over to the basket of positive stability. Therefore I am interested in exploring what options and technology is available beyond the 90 degree mark rather than the reliance on ever increased amount of positive buoyancy before the 90 degree mark such as wider beams and heavier loads.

I personally think two hulls are great but I also believe that the equal distribution of weight above is also its Achilles heel which many turn a blind eye to. Even a turtle and tortoise have a solution to capsize given by nature and I think we should have a solution for capsize, full or partial rather than trying to mitigate the risk with more of the same all the time which is positive stability.
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Old 18-05-2015, 05:02   #157
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Re: Is there a catamaran of cruising size that can self right unaided?

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Well, now you have started to enter into reasoned dialogue(thank you) I will start to listen.

The issue I have presented here is not one which tries to consider holistically that which is more safe, i.e. two hulls versus a single displacement one but the dynamic of capsize itself. In this respect the conclusion of capsize for a cat is generally fatal.

The overall flaw of a cat is that it is contemptuous of nature. Its design philosophy is to resist rolling with all eggs given over to the basket of positive stability. Therefore I am interested in exploring what options and technology is available beyond the 90 degree mark rather than the reliance on ever increased amount of positive buoyancy before the 90 degree mark such as wider beams and heavier loads.

I personally think two hulls are great but I also believe that the equal distribution of weight above is also its Achilles heel which many turn a blind eye to. Even a turtle and tortoise have a solution to capsize given by nature and I think we should have a solution for capsize, full or partial rather than trying to mitigate the risk with more of the same all the time which is positive stability.
When not considering the whole picture, you often come to incorrect conclusions.

Capsize in any boat is generally a really bad thing. In offshore storm conditions with no help close at hand, there are good odds capsize in any boat will be fatal. To describe it as the Achilles heel implies this is an issue unique to cats, which is incorrect. Near shore, I would much rather have a large easily found upside down hull to cling to.

The solution to capsize is not to capsize. If you are halfway competent, the odds of capsize in a well maintained boat is negligible. Yes, there is always the risk but it's so small, that other risks outweigh it.

You are trying to solve a problem that's not worth the cost of solving.
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Old 18-05-2015, 05:05   #158
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Re: Is there a catamaran of cruising size that can self right unaided?

I think a big part of the resistance you are getting is .you claim to only want to discuss catamaran capsize and righting but then irrationally defend monohulls as being intrinsically safer on the whole
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Old 18-05-2015, 05:29   #159
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Re: Is there a catamaran of cruising size that can self right unaided?

Perfect multi hull... Nearly.

Such a cool design..

Harryproa Cruiser 60 |

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Old 18-05-2015, 05:55   #160
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Re: Is there a catamaran of cruising size that can self right unaided?

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Perfect multi hull... Nearly.

Such a cool design..

Harryproa Cruiser 60 |

If we go by your recent statement that this thread is purely about being self righting, you are in the same position. Once it turns turtle offshore in a storm, there is no viable means to right it.

While I do find the proas interesting, when you start digging into them as cruising boats, they come with major compromises.
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Old 18-05-2015, 06:04   #161
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Re: Is there a catamaran of cruising size that can self right unaided?

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I think a big part of the resistance you are getting is .you claim to only want to discuss catamaran capsize and righting but then irrationally defend monohulls as being intrinsically safer on the whole
With respect to capsize mono's are safer.. They can recover. I concur that a breached hull of mono will sink but my focus is capsize and not loss of displacement. - cats have won this battle.

Why would you not be interested in a cat that has capsize defence beyond the point of no return? Not sure why you would not want that.
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Old 18-05-2015, 06:41   #162
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Re: Is there a catamaran of cruising size that can self right unaided?

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With respect to capsize mono's are safer.. They can recover. I concur that a breached hull of mono will sink but my focus is capsize and not loss of displacement. - cats have won this battle.
There is much debate about the new 'beamier' monohulls being able to recover from a 90+ degree knockdown.

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Why would you not be interested in a cat that has capsize defence beyond the point of no return? Not sure why you would not want that.
For the same reason I don't wear a parachute on an airplane. Both needing a parachute while flying and capsizing a modern cruising catamaran are so statistically insignificant, it's a total waste of time.

And if such does happen, what guarantees your invention will work in whatever conditions caused the capsize in the first place???

This may be a fun mental exercise, but unless you design/build your catamaran with the highest priority requirement being recover from capsize, you waste lots of thought cycles better spent on learning how to sail (hint!).

Go forth and build/retrofit your catamaran with whatever invention you dream up. In 15 years when you're ready to shove-off, holler and we'll tell you the best destinations, as we'll have already been there!

A classic case of analysis paralysis.....
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Old 18-05-2015, 06:53   #163
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Re: Is there a catamaran of cruising size that can self right unaided?

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I backed it up some time ago. I did a like for like quote. We moved on from that subtext of the thread quite a while ago but If you have some retrospective compelling argument or proof to the contrary rather than insult then post it. Hopefully though it will not be an echo of every other manufacturer.

Also you could type the words - Catamaran, Capsize and Dead in google and read what that returns.

Forgive me my own assertions as my family is mine and not yours. "Its ok honey, we can go to the Falklands. valhalla360 says cats are perfectly safe and equal to mono's" - Yeh right.

Maybe the delivery company, Reliance that sent the crew of the 40ft cat "Catshot" into a force 9 and certain death had the same idea as you. Cats, rock solid they are. - Funny they found it overturned in such light winds.
no, I don't think so, that sheet re the insurance quotes was not the data you asserted you had in the early post..just callin' it as I see it
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Old 18-05-2015, 07:19   #164
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Re: Is there a catamaran of cruising size that can self right unaided?

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no, I don't think so, that sheet re the insurance quotes was not the data you asserted you had in the early post..just callin' it as I see it
May I refer the honourable member to comment #147
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Old 18-05-2015, 07:27   #165
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Re: Is there a catamaran of cruising size that can self right unaided?

Hey c'mon all, isn't it a vary positive thing that someone tries to study and improve sailing related techniques. Even if the outcome would be that no new useful ideas were found, the idea of seeking improvements is still very good, and this kind of activities should be encouraged.
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