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Old 19-05-2015, 21:40   #256
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by rabbi View Post
a nearshore capsize does not require self righting. There should be help available in acceptable time, for both righting and lifting off the crew.

Offshore it can happen in moderate weather only if you get caught by a squall while sleeping. Simple operator error. Darwin's rules apply.

In heavy storm conditions it can happen but there is no way of self-righting.

Just think about the situation you will face.
most equipment will be washed out or damaged. No electricity. Diesel everywhere, maybe also acid and fumes from the batteries.
The crew is tired from the last few hours or days in the storm. They are bruised or someone may be severely injured, missing or dead. It will be days of survival mode in a liferaft or dinghy before you can even think about righting the boat. After these days the condition of boat and equipment will be even worse. Whatever clever mechanism is implemented is almost certain to fail.

If you succeed the boat is full of water and therefore with almost no stability. A small push from a wave and she will capsize again before you have a chance to pump out. All batteries are dead, so this takes time.
If you finish manually pumping out tons of water. you would have a barely floating wreck with dead engines, likely torn sails and twisted running rigging. Or maybe even no mast. You could jury rig something but that won't bring you back home from high latitudes.



Your only hope is capsize prevention. Look into things like the jordan series drogue.
once in a while it seems something good rises to the surface

Some good points,

makes me think about gas proof lockers and sealed lead acid batteries, or perhaps exchange them for a better battery technology. It is interesting that despite the well known risks to crews from chlorine gas only one submarine manufacturer offers lithium battery tech.

It occurs to me that if you minimise the risks with a sensible rig, one with a lower centre of effort such as ketch or schooner rig with squared off tops. Then your chances of being blown over are rather less, and it then requires many more tons of force to blow the boat over. Add to that the cat rigs such as the Freedom type or Presto 30 rigs allow the masts to bend and reduce force, and they can swivel in their bearings to feather and dissipate traverse force completely. The masts also provide a measure of buoyancy pulling an inverted cat back to 90 degrees.

Allowing that we had done all we could do about the rig there is still wave action roll over. I remember the Iroquois catamaran propensity to go over was something to do with her centreboard keels, perhaps just ensuring that the correct side grips and the opposite allows transverse flow by adjusting the hull profile is a worthy fix. Again its that need for an asymmetric hull design that keeps popping into my head as it shows some potential for anti-slamming too.

It doesnt matter how bad the situation is on an inverted boat, you are still better off on the boat than in a raft. People have survived in inverted catamarans many many days after having gone over, perhaps there are ways to enhance that survival. If you still have an electric system then you can still pump water and have a better survival capsule.

It seems to me that no matter what it is, the boat that doesnt go under is a far safer proposition
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Old 19-05-2015, 22:38   #257
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by valhalla360 View Post
While I do find the proas interesting, when you start digging into them as cruising boats, they come with major compromises.
What would these be?
.................................................. .....
I disagree that anti capsize is a solution looking for a problem. Not necessarily a safety problem so much as a passage speed and stress problem.
Read all the threads about reducing sail early or at night, sailing downwind in strong breeze underpowered in case you need to luff, sailing for the forecast instead of the actual conditions, tacking instead of gybing, zone of death, sailing safely, not pushing the limits, operator error, etc, etc.

These are all results of having a boat that can, and will, capsize. If reliable anticapsize devices and/or sailing techniques were used, then cruising multihull passage speeds would increase significantly and more importantly, the level of stress onboard would go way down.

The most significant of these devices/techniques is an unstayed rig.

The ability to release one sheet and have the boat instantly depowered, with the sail(s) sitting quietly and pointing into the wind on any point of sail is a huge stress reducer/performance enhancer. Connect the sheet to a floating fuse and you are close to an uncapsizable multi. Not as idiot proof as a lead keel, but a lot closer than the current crop of cruising cats with their "sail slow, sail safe" requirement.
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Old 19-05-2015, 23:43   #258
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by doublewide View Post
A cat is more stable upside down than right-side-up. Thus, it takes more force to right one than to capsize one.
A monohull is maximally stable at the bottom of the ocean.

Your cat should come with a reefing table that tells you the maximum sail to carry for every point of sail and wind speed combination. Reef appropriately and you will be safe.
That is just wrong. Reef appropriately you will not be safe. You will be safer.
You can get just plain unlucky and get hit by 60 knots which came from nowhere (plenty of cases of that happening particularly in the Med). There are also tales of cats being flipped by such cases in the Med - particularly in the Golf de Lion region. There are also many tales of monos being severerly beaten up as well. Every year a few boats seem completely disapear in the Med - cataramarans and monos.

You can flip a cat with no sail up, when going too fast down a steep wave (where a mono would broach).

On the sea despite expecting the unexpected, sometimes you still get surprised.
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Old 20-05-2015, 00:13   #259
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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
I know he is sailing Hobie's but I asked him for his experience and he gave some insights that probably do translate to a bigger class.

He mentioned that the minimum weight in still waters to bring the cat up is a 3rd of the boats top weight which the crew must equal unless they need external assistance. He also mentioned the issue of righting which can cause the cat to mediately capsize again due to the inertia caused by acceleration of the top side mass.

He also mentioned technique which with respect to leverage which would also apply in similar fashion but of course be done mechanically.

Interestingly I also spoke to an insider today that tells me that ISO are looking to impose a need for cat certification to stay at 90 for a certain time up to mid size so clearly the problem is being addressed and is regarded as one. I have also been told there are some clever minds behind the scenes working on workable solutions to this problem.

However, I imagine the standard will require a time delay before total inversion based on a test in a mill pond and I think it is aimed at the charter sector to give people a chance to evacuate properly rather than to bring the boat back up never the less it is a step in the right direction.

Leave it to the Brits.. We will sort it out for yer.
As a Brit if you are serious about a cat organise a visit with Darryl Newton of Dazcat at Millbrook.
.
He is probably the most experienced designer/builder/racer of catamarans in Britian and could give you plenty of insite.

He has many designs including a Southern Ocean 45 designed for the Southern ocean.


Design Concepts
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Old 20-05-2015, 01:34   #260
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Re: Righting a Catamaran

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Originally Posted by paulanthony View Post
Did you see this Juho? You may like it. I think it can get back up. Harryproa Cruiser 60 | Probably equivalent to a 40 foot cat if you dismiss the overhangs but if it will do what it says on the tin it will be quite impressive.
Yes, that's one approach that might help keeping the boat upside up in many cases. (not excluding the possibility that also the most typical designs could be improved)
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Old 20-05-2015, 01:38   #261
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by doublewide View Post
A cat is more stable upside down than right-side-up. Thus, it takes more force to right one than to capsize one.
That is not necessarily true. An inverted cat will be (partly) flooded and water moves around as you try to right the cat. So stability figures will be lower than for an empty upright cat.

Which does not mean its possible with onboard solutions.
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Old 20-05-2015, 01:50   #262
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Re: Is there a catamaran of cruising size that can self right unaided?

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A fixed float needs to be huge for a large cruising cat. The weight and windage will increase the risk of capsize.
A selfinflating device needs to inflate very fast. More like an airbag than like a PFD. plus it needs to be very tough to survive rubbing against shrouds, masthead, lights, etc

I can't calculate this but I am sure it will fail for a pitchpole. The forces will be violent and the waves will add to this. Maybe it could work for a flip over the side but i don't think so.

A reliable device would need significant development and testing effort. Way more than any manufacturer will ever spend on this. Especially since there is no market for such a device. The risk is too low for > 90% of all cat owners
A simple self inflating device might be cheap enough to justify installing one, at least for some boat owners, even if it does not save the boat in all situations, and even if it might be needed only very seldom.

I think it would make sense to test this kind of devices. Maybe boat manufacturers don't want to advertise the possibility of boats flipping too much, but certainly it would make sense to make tests to see if this can be done and if this approach works. Not too expensive to use some old catamaran for the tests.

There may be some potential catamaran owners that would be interested in buying all possible safety features. If the device is not efficient enough and cheap enough to be installed in all new boats, it would be just an optional feature for those who want it.

All serious testing gives some new potentially useful information to us. Here's one test with a monohull.
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Old 20-05-2015, 01:54   #263
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by valhalla360 View Post
Google: Roll Moment of Inertia. The weight aloft will make the boat more likely to roll. Self righting catamaran designs are a solution looking for a problem.
Already one associated loss of life, or few losses of expensive boats, makes this a problem looking for a solution to me. No guarantees given on finding a cheap enough and a working enough solution, but certainly worth some thinking.
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Old 20-05-2015, 01:59   #264
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by med View Post
You can get just plain unlucky and get hit by 60 knots which came from nowhere (plenty of cases of that happening particularly in the Med). There are also tales of cats being flipped by such cases in the Med - particularly in the Golf de Lion region.
The coastal areas of the Med are know for heavy blasts but in these areas help is just a phone / epirb / satphone call away. Since saving our lifes is for many of us more important than saving that damn wreck I would be lifted off.


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You can flip a cat with no sail up, when going too fast down a steep wave (where a mono would broach).

On the sea despite expecting the unexpected, sometimes you still get surprised.
Pitchpoling from a breaking wave is not unexpected or surprising but well known (in theory).

This thread is distracting the focus from what you can do (reef early, stay alert, have a drogue, etc) towards what you can't do (safe a flipped cat offshore).
Read the Storm tactics book and look into the JSD or similar devices. Both is far more useful than the outcome of this thread, which I hope no novice cat sailor will take seriously.

The dream of self-righting in offshore conditions bad enough to pitchpole is a pipe dream. Even if it works in theory it will fail in practice, and any effort (time and money) spent on this is better spent on reliable life saving equipment and preparation.
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Old 20-05-2015, 02:15   #265
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Re: Is there a catamaran of cruising size that can self right unaided?

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If you still have an electric system then you can still pump water and have a better survival capsule.
You'd need completely dry, separated, isolated and sealed batteries. Even if you have a special locker for them the seawater will create shortcuts in all circuits which will run down the batteries.

Your best bet with regards to electricity after capsize is a small solar charger for the minimum stuff you need (satphone, DSC VHF, flashlight). And some spare batteries
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Old 20-05-2015, 02:40   #266
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Re: Is there a catamaran of cruising size that can self right unaided?

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A simple self inflating device might be cheap enough to justify installing one, at least for some boat owners, even if it does not save the boat in all situations, and even if it might be needed only very seldom.
How many serious cruising cats are currently out there? I really have no clue but lets say 30.000.
How many folks are travelling offshore and may be interested in such a device? Lets say 5%?
That's a potential market of 1500 devices, but you will reach only a fraction of this market. Maye 2/3 of those that might be interested will never hear about this device or will not be able to buy it.
That leaves 500 devices to be sold. But this includes different devices for a small 27ft Heavenly Twins and a 145ft Hemisphere and everything in between.

You can play around with the numbers but the overall dimensions should be clear. You would be selling a handful per year.
If it becomes mandatory for new cats in the EU it will be maybe one hundret per year. The others go to different regions.


Do you think any manufacturer will invest a 6digit figure to claim this non-existing market to solve a problem that can't be solved reliably? A problem that is not even considered a problem by most?

Unless some UK bureaucrat comes along with some sort of ISO requirement. Which is the best way to increase new boat prices and provide a false sense of safety. This would lead to even more fatalities (hey, my boat can't flip and can't sink so why I don't need to be prepared )
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Old 20-05-2015, 03:55   #267
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Re: Is there a catamaran of cruising size that can self right unaided?

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All serious testing gives some new potentially useful information to us. Here's one test with a monohull.
There are monohull designs that do not need active devices to right themselves, they use the buoyancy of the boat combined with the curve of the coachhouse and the pendulum effect of the ballast.

The curve or tumblehome of the coachouse floating inverted on its marks sets up a relationship where it is impossible for it to come to rest which ensures the boat must fall back over and right itself

Im a little surprised this is apparently not universal as the principle has been well understood for decades.
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Old 20-05-2015, 03:56   #268
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by valhalla360 View Post
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.
I can see a way simply by looking at this image whereby it could very easily(impossible to do with a cat) become an automated task to recover. I will hold back till after I speak with some of my "secret contacts" but if you keep looking at this picture and that of a cat you will be able to discern one very big difference.. Here is a clue. The centre line is 100% unobstructed from nose to tail.
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Old 20-05-2015, 04:00   #269
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Re: Is there a catamaran of cruising size that can self right unaided?

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Originally Posted by rabbi View Post
You'd need completely dry, separated, isolated and sealed batteries. Even if you have a special locker for them the seawater will create shortcuts in all circuits which will run down the batteries.

Your best bet with regards to electricity after capsize is a small solar charger for the minimum stuff you need (satphone, DSC VHF, flashlight). And some spare batteries
Gas tight chambers are of course completely dry

On power supply; what happens is shorting occurs, all the breakers blow, but there are sealed emergency circuits to provide an amount of functionality, for which lighting and pumping are common.
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Old 20-05-2015, 04:42   #270
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Re: Is there a catamaran of cruising size that can self right unaided?

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As a Brit if you are serious about a cat organise a visit with Darryl Newton of Dazcat at Millbrook.
.
He is probably the most experienced designer/builder/racer of catamarans in Britian and could give you plenty of insite.

He has many designs including a Southern Ocean 45 designed for the Southern ocean.


Design Concepts
Thanks for the link.. I will check out his philosophy.
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