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Old 18-08-2010, 12:02   #196
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If true that this is the largest sized cruising cat to flip then it is both concerning and reassuring. I don't think multi owners or those considering catamarans need to panic. In my mind for me, catamarans are superior and safer. Don't want to rehash this debate but the fact that this is the only cruising cat of this size to ever flip is intereting. I am considering an Outremer 55, another preformance catamaran. Yes I will have to figure out the capsize equation (does anyone know the CE of this cat or another way to figure this out) and when to set what reef. Microbursts scare the heck out of me and are a real danger. But these are great crusing vehicles and for me and my family as safe or safer than other boats at this price and size for many reasons. Ultimatly sailing a small sailboat on the open ocean involves risk managment. Microbursts are a big scary one and stories like this drive home that point and will hopefully cause us to be prudent.
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Old 18-08-2010, 12:04   #197
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Originally Posted by estarzinger View Post
Is releasing the mainsheet a 'sure cure'?

Let me pose the question . . . for a bluewater doublehanded boat . . . what squall wind speed do you think it should be able to handle with full sails without being able to flip?? It's all good and well for us to say we will all always be excellent and prudent seamen. but remember that we all (and apparently even Mark with his velvet lined leash) make mistakes.
This is a very good point and I for one would like to know this number for my current cat (Seawind 1000) and my (hopefully) future cat (Outremer 55 standard).
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Old 18-08-2010, 12:07   #198
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The barometer had dropped only from 1000 mb to 998 mb over the last few hours, which was no cause for alarm
I'm almost speechless...
There is a big red warning sign, that goes unnoticed. The average pressure in their position is around 1015.0 in august. 15 millibar under and still falling. It is more or less certain that there is a tropical system in the vicinity even without other information. Then .. you see an unusual black cloud.... I would be very apprehensive in a situation like that, and start thinking about microbursts (that you need a doppler radar to spot)..
These two facts in themselves warrants reefing down to your last reef and expect the worst.

You don't stay in the Wheelhouse i a situation like that! You don't let the autopilot steer! To get situational awareness, steer the boat yourself, listen, look and smell the wind and the Sea, and you will have an advance warning.
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Old 18-08-2010, 12:35   #199
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Have you ever seen a highly loaded sheet (maybe 8~12 tons on an Atlantic 57?) running free when the pawls strip? Are you sure you want that on your boat?
I think it would be better than a capsize. As you point out, with those loads, it is hard to release standard set ups quickly without getting into trouble.

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I guess I am not very happy with a 'solution' that suddenly released the mainsail totally free . . . that could easily kill someone.
Capsizes kill people too. Hopefully, nobody would hit the release if someone else was standing on deck in the path of the boom. There could be a preventer that stopped the boom short of the rigging.

Frankly, I would probably go the other low-tech way on my own boat. Use non-self tailing winches and a standard horned cleat that would allow you to slip the sheets in a controlled manner, but they would be a pain most of the time on such a big boat and I'm not sure you can react fast enough.
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Old 18-08-2010, 12:46   #200
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Why are you suprised? You've been around the block a couple times and know the only predictable thing about being on the water is that it's unpredictable. Isn't better to be on a boat that can take care of itself when we screw the pooch?

For what it's worth, water is held at bay if seacocks and hoses are maintained, hatches are dogged when underway, and watertight bulkheads are installed.

Without doppler, how do we see the wind?

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Originally Posted by estarzinger View Post
my surprise was fundamentally that this could happen in the first place.
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Old 18-08-2010, 13:00   #201
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I think some here are getting somewhat 'liberal' with the facts in order to advance their own opinions concerning mulithulls- the boat did not capsize (nor was it close to capsizing) at 40 knots of wind or less. The last noted wind speed was 62 knots and it seemed to be increasing thereafter.

Further, some are also attempting to make sweeping generalizations about all mulithulls based upon what happened (or in the case of the deliberately understated wind conditions at the time of capsize -what didn't happen) to this particular multihull. I konw, good fun for cat bashers, but not very helpful.

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Old 18-08-2010, 13:15   #202
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As has already been discussed, one can always rig a 'reverse' jibe preventer - inotherwords, a line to the boom to prevent it from contacting the aft shroud in the case of a sudden release of the mainsheet. Yes, you might damage the boom (especially if it is lightly constructed), but you shouldn't lose the rig.

For those who think that a microburst (and that is certainly what this appears to be from the description) can only affect a multihull, we should remember the Canadian flagged training vessel that capsized and sunk in the Atlantic under similar conditions this spring. Having said that, I am not going to resort to the tactic of concluding that all monohulls are therefore similarly vulnerable to sinking in similar circumstances - BECAUSE THEY ARE NOT!

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Old 18-08-2010, 13:17   #203
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Although mentioned a few times on this thread, I don't think enough consideration has been given to the possible contributing effects of sea state and wave action. Sometimes waves / currents / swells simply combine in a way that affects the motion (stability / CoG) of a vessel out of all proportion to the size of the waves. or the wind. Sea alone (unless a mighty wall of water!) might not roll over or flip a boat on it's own, but in the right (wrong) circumstances might aid in tripping her in a normally acceptable wind strength.

Inshore or offshore lots of things going on with the sea - below as well as above.
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Old 18-08-2010, 13:37   #204
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Its good to get the full report from the guys on the boat, not just speculations on what might have happened. The lesson is pretty obvious for cat owners-- crusing cats can flip in sudden gusts, even in moderate sea states. They will not tolerate being overcanvassed, and should be sailed accordingly. Once you start to lift a hull, you have less than a couple of seconds to release the mainsheet or you will need rescuing.

The cat owners and promoters can spin this anyway they want, but they need to be aware of the reality. Most cat owners don't push their boats as hard as Anna was, but stronger gusts can happen, and each cat has its limits. These gusts don't just occur off Niue--I got hit with over 65 knots in a squall in the Delaware Bay this summer.
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Old 18-08-2010, 13:41   #205
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Quote:
Originally Posted by Southern Star View Post
to advance their own opinions concerning mulithulls- the boat did not capsize (nor was it close to capsizing) at 40 knots of wind or less. The last noted wind speed was 62 knots and it seemed to be increasing thereafter.

. . . Sweeping generalizations about all mulithulls based upon what happened to this particular multihull.
Are you the builder of the 65' southern star cat, so have a vested business interest in this?

I am not a multi basher . . . in fact as I said, I have been trying to convince my wife to get one (I posted a link to the design in a post above).

This is the crew's direct report. http://blog.mailasail.com/syanna/14 The way I read it they were in fact very concerned about capsize at 40-45kts apparent. The "60kts" is very speculative "he thinks he saw (he is not entirely certain)". Also the way I read the description this is just the sort of squall conditions that we have experienced perhaps every two years at sea . . . although usually at 2am rather than in the afternoon.

Again, as I said several posts ago, this capsize contradicts the generally held theories about cruising cats ( "bigger than 50' can't capsize" or "can't capsize except in the most extreme conditions") and I am just trying to understand given the new facts (of this incident) what the truth about these performance cruising multihulls is and how it might/should effect my thinking.

If you were involved in the 65' cat . . . what wind strength would flip her with full sails? What do you think is an acceptable standard for a double handed boat?

Regarding reverse preventers: I have not seen one used in practice and I can guess why: (a) a reverse preventer would be a piece of line that would be a real hassle most of the time, (b) it does not solve the problem if the fuse lets go and someone is standing in the way, and (c) boy it better be strong. . . . just think of the shock loading on a 'reverse preventer' if the boom is let go from tightly sheeted in 40kts
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Old 18-08-2010, 13:59   #206
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Actually the Concordia is NOT a modern self righting mono hull. It is a ballasted ship and is prone to capsize. The history of the modern self righting mono hull is fairly recent and has only come about in the past 100 years. Modern materials needed to build a self righting monos were not available before then.

But, the discussion is about the Atlantic 57 that capsized. To develop a solution the problem must be understood, to define the problem fault has to be found. Where does the fault lie? The sailor, the builder, the designer, the concept or God?

The owner of the fault is what we are all interested in.

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Originally Posted by Southern Star View Post
As has already been discussed, one can always rig a 'reverse' jibe preventer - inotherwords, a line to the boom to prevent it from contacting the aft shroud in the case of a sudden release of the mainsheet. Yes, you might damage the boom (especially if it is lightly constructed), but you shouldn't lose the rig.

For those who think that a microburst (and that is certainly what this appears to be from the description) can only affect a multihull, we should remember the Canadian flagged training vessel that capsized and sunk in the Atlantic under similar conditions this spring. Having said that, I am not going to resort to the tactic of concluding that all monohulls are therefore similarly vulnerable to sinking in similar circumstances - BECAUSE THEY ARE NOT!

Brad
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Old 18-08-2010, 14:05   #207
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catamarans are different than monos

On a catamaran you should almost never turn into the wind in an overpower situation. Anna makes for a good example if the information found in this thread is correct. During micro bursts it is not uncommon for the wind to shift as much as 180 degrees. He stated he was monitoring apparent wind speed; this is also what he and the boat would be sensing without his instruments along with apparent wind direction. He stated that the wind had shifted to the beam. On a catamaran if the wind is on the beam because of the boat speed which although not specified, on that particular cat could have been 20 knots in that situation, the true wind would have been well aft of the beam. By turning off the wind he would only have to turn 10 to 30 degrees before he would have put the wind way behind him and would be subtracting 20 knots of boat speed from the true wind speed. 40-20=20. He would also be using the 57 feet of boat length for stability as opposed to his 28 foot of beam. By turning into the wind he would have to turn through 80 to 120 degrees all the while increasing the apparent wind speed as he would be adding his boat speed to the true wind speed. 40+20=60. Although the numbers I present are theoretical and perhaps overstated for effect, the fact is fast catamarans bring the apparent wind well forward thereby making it a long turn into the true wind. I can not speak from experience on the dagger board issue but from what I understand one should deploy the windward board, not the leeward board to prevent tripping.
2 cents from this cat sailor.
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Old 18-08-2010, 14:15   #208
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Another thought on modern cats is that they basically have slab-sided hulls that do less to prevent a capsize than older designs that had a lot of flair. The most blatant example of flair being the Wharram V-shaped hulls. Wharram claimed that in the event a boat was tipped up by wind or wave the V-shape would tend to resist capsize. I used to pooh-pooh this idea until I was hit on the beam by a breaking wave offshore in my cat (with V-shaped hulls) which tilted the boat up enough to send everything sliding to the low side, almost like a mono being knocked down. But the boat surfed sideways for a bit and then slammed back down level. Not saying that a V shape is the best for a cat, as there are other disadvantages, just that I suspect hull shaping could be used to make larger cruising cats more resistant to capsize.
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Old 18-08-2010, 14:22   #209
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Originally Posted by Joli View Post
Where does the fault lie? The sailor, the builder, the designer, the concept or God?
One thing you can say about this incident is that fault is NOT with the rig builder. One big cat owner I know well has always said his rig would break before the cat capsized. The rig held together here.

The mainsheet did not rip out of the deck when the hull started lifting, and the hull looks pretty intact both on the rescue and after coming aground after being upside at sea for a while. So, probably some credos for the builder.

We know the sailors screwed up, but that's too close to home so I can't find fault there . . . more seriously I think a double handed blue water boat needs to be resistant to quite a high level of sailor screw-up. I think the hull needs to be able to take a reasonably hard grounding without coming apart because we all go aground sometime, and needs to be able to come thru a squall without loosing its rig or flipping because we all are occasionally surprised by a squall's strength.

I don't lay this one on god or fate. It's possible that this was truly extraordinary 'once in several lifetimes' weather, and that's 'the answer' for some of the multi-hull camp. But for me, the weather sounds common enough, and the crew failing common enough, that this exact situation had to be expected and designed for and planned for

So that leaves the question I was trying to answer . . . is this particular design not suitable or is the concept/class not suitable for short handed blue water? I have not heard any real facts yet to help me sort that out. The simple comparison vs the gunboat made the class look suspect, but that's too simplistic an analysis to take too seriously.

Does anyone know what the real displacement of this boat/design was? The website says 26,500lbs, which I thought is too light to be believable and builders/designers are notorious for posting way light displacements. But if that's actually true, perhaps this design is way too light, leading to too small righting moment for the sail area, making it the designer's fault.
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Old 18-08-2010, 14:32   #210
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There are a number of worrying things about the account and I think MarkJ is right on target. I'll just add that a 998 bar and down two recently in that area along with a distinct cloud line is almost always a sign of serious weather. I don't know what the weather charts were showing but WYSIWYG. So, I've given up on the unpredictable microbust as a contributing factor in this case.

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Yes, that was the old theory/debate . . . but that's just simply not true if they will/could flip in 30-40 something true. We have been caught multiple times in 'sudden/unexpected' 2am squalls with +40kts true . . . just guessing but perhaps once every two years or perhaps a bit more frequent than that. We have actually not sunk (yet)
Didn't Beth research this for a book that included a section on multihulls? One of the most accessible papers on the subject is Multihull Design Considerations for Seaworthiness

There are generally two different categories of stability (static and dynamic) and within them a number of distinct considerations. It's too much for me to cover all of that while I drink my morning coffee. But my attempt at a brief and shallow summary is:

The reality is that multihulls have a good safety record. Giant multihulls that can be sailed over in less than 10 knots of wind have been single handed across oceans and even non-stop around the world. Okay, Joyon is a superman. But consider the time and effort it takes to reef or even trim sheets on a boat of that size and power. And consider the stability needed to stay upright while hooked into powerful lows deep in the Southern Ocean.

How is it that a boat that can be flipped in a mild breeze can also navigate the Southern Ocean's storms with a single man as crew and still make extraordinarily fast passages? Certainly, a large part of the answer is the "tiller nut". But there are design considerations too. I think the key to understanding this and answering your concern about flipping in some particular amount of wind (pick a number any number) is to understand that a designer can always design a rig that will use all of the available stability at any particular wind speed independently of the actual value of stability. IDEC, for instance, has a huge amount of stability, more than many ships and vastly more than any conventional monohull of a similar length. She also has an enormous rig that can develop enough heeling force in a mild breeze to capsize the boat. The designer could easily have put a smaller, shorter rig on her that would not need to be reefed in 40 knots of wind or 50 or 60... Of course, within limits, the same thing can be accomplished by reefing the large rig.

I've used Joyon and IDEC as an example because the boat is huge and powerful and it was sailed by one person suspected of being human. But the same design considerations apply for mortals sailing lesser craft. A designer can put as much rig on any boat as he or she feels is appropriate to the service independent of the amount of stability the boat has. Smaller rigs are largely equivalent to reefed larger rigs. When a designer chooses a rig size to some extent he is making a judgment about the expected abilities and tastes of the crew rather than determining the ultimate seaworthiness of the craft. Or, put another way, a boat that comes from the builder with a rig that doesn't need a reefed at 40 knots may not be any more stable than a boat that needs to be reefed at 15 but is clearly designed for a different user. Equally, a boat that needs to be reefed at 15 but is sailed with reefs for 40 will perform similarly to a similar boat that has a cut down rig designed for 40 knots. In short, designed reefing points tell you who the boat was designed for but not how stable it is. A fast boat can be sailed slowly but a slow boat is always slow. A fast boat may or may not have lots of stability and the same is true of a slow one. All else being equal a more powerful boat needs to be reefed earlier than a less powerful one.

So, IMO, the answer to is a multihull that can flip in X amount of wind safe for crusining depends both on who's driving and how much stability the boat has. But, just knowing how much wind will capsize the boat doesn't tell us how much stability it has much less how seaworthy it might be. There is a danger in assuming that a multihull that will not capsize with full sail at 40 knots is inherently more stable or seaworthy than one that needs to reefed earlier. One may reasonably infer that the more conservatively rigged boat is intended for a more conservative audience that does not want to be bothered with reefing as often and doesn't want to pay extra for the "privilege" of working harder. However, one must not assume that the less conservative boat is less stable. When considering seaworthiness I believe it is important to remember that the sea is the same size for all boats. More so than in other design questions ratios used without regard for absolute size can be misleading. Static stability for a multihull is fairly easy to calculate with reasonable accuracy. Roughly speaking the static stability will be a bit less than 0.5* the distance between the centers of buoyancy of the hull times the displacement. For what it is worth heavy "cruising" style cats generally have less effective beam because their centers of buoyancy are more inboard and they also tend to have less beam overall. They do tend to have good static stability because of their greater displacement. However, dynamic stability and seaworthiness are more complicated. For similar reasons that a monohull with its rig intact may be more resistant to capsize in waves than one without a rig a wider multihull is more resistant to capsize in waves than a narrower one. Also related a multihull with is weight distributed farther outboard (transversely) will have more resistance to wave capsize than one with a more central distribution. So, larger, wider multis with narrower hulls are expected to be more seaworthy than smaller, less beamy mulits with fat hulls. I recommend the Shuttleworth paper for details.

IMO, then, if considering a multihull for cruising one should consider the question of power (at what point will she capsize) and seaworthiness independently. The fist is all about how often one wants to reef and how much one wants to pay for rigs and sails and the latter is largely a function of beam and weight. Assuming, of course, competent design -- in the same way it is possible but stupid to put a 400 horse power engine into a minivan with standard breaks it is possible to make an overpowered difficult to control multi that would be dangerous in any but the most skilled hands.

Quote:

I am just trying to recalibrate my thinking here to these new facts.

Just for kicks:
Gunboat A57
LOA 66 57
Beam 22 28
Mast height 87 78

Just looking at those numbers I would have thought the A57 was rather more 'squall resistant' than the Gunboat (Which has less beam and more mast)! I don't know what the real displacement for the A57 would be, as the number on their website is obviously hyperbolic. Perhaps the Gunboat is a lot heavier, but you would not think so from their marketing or pricing.
The Gunboat is not heavier (all else being equal). But the question is meaninless without a knowledge of how much sail each is carrying rather than the potential sail they might carry. The gunboat is a much more powered up craft when full sail is set and it has less static and dynamic stability. But as we all know it is still quite possible to sail to sail the A57 over. Keep in mind that reefed down to the point that it was in no real danger of capsize in a 40 knot gust either of these boats would still be pretty quick by most standards. The power is there but there is no requirement to use it all.

My coffee is calling must run!

Tom
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