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Old 28-12-2010, 16:26   #46
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SPHINCTER FACTOR OF 10, Paul!

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Old 28-12-2010, 16:36   #47
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Old 28-12-2010, 16:47   #48
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Wow, thank you to all those who have contributed stories. Also, thank you to the folks who contributed lively discussion. My interest in the subject was piqued by an article I just read in a science magazine, thus prompting my starting the thread, and I had noooo idea it had a controversial aspect! Overall very interesting.
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Old 28-12-2010, 16:51   #49
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Old 28-12-2010, 18:42   #50
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Paul, thanks for your story! so being a newbie sailor, with big waves like this, is Paul's stategy the best or is there other options, depanding on how big the wave is? Does it matter if you are on a cat or a mono?
Thanks!

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Old 28-12-2010, 20:22   #51
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Neither a typical cruising multihull or monohull is suited to such a sudden HUGE wave. To survive is quite extraordinary! It is good that they are so seldom seen.

In my little tri, IF I was to see it coming I would attempt to surf down it at great speed, and probably pitchpole at 20 knots in the trough. Still, that would be my only option.

I suppose the same would be true for a typical cruising monohull, except it would go slower, so be overtaken and pitchpole on the way down.

Neither would have the engine power, (small cruising sailboats), to motor up it without stalling and eventually flipping backwards.

The best boat here would be about a 50', flush decked, metal monohull, with a very short or no mast, large engine, high ballast ratio, no ports, stantions or external protuberances at all, and only one hatch. That one hatch would be a gasketed screw down like a submarine, and you would have to see the huge wave in time to secure yourself in. In other words, the boat would be useless for anything else!

Also, everything over 5 grams down below would have to be fastened down!

Paul did the right thing, it's an amazing story...

It is not likely in this situation, for the average small cruiser of either variety to have time to do anything but "punt" and hope for the best! To many variables to really know.

The more normal kinds of nasty weather is 100 times more frequent, and gives 100 times more opportunity to prepare for, so this is what good boats are designed to withstand, and what we need to learn to deal with...

Having been there, I'm sure Paul's opinion has more merit though...

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Old 28-12-2010, 22:56   #52
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G'Day Troppo,

Actually, most of the freaks I see don't wave at all. Sometimes a rude gesture, but hardly ever do they wave. And they are seldom nearly that tall...

Jim and Ann s/v Insatiable II lying Church Point, NSW, Oz
Ah, Jim, I don't think we have ever met but maybe you saw me somewhere as your description is accurate . . .


says the original rude short arm-waving freak.
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Old 28-12-2010, 23:02   #53
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Gee, guys, I'm on deck 6.5, at least fifty or more feet above sea level, and look what's coming!

Markpiece, can you tell us more about this story? Where was it? What happened? And most importantly, what was on the menu?
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Old 28-12-2010, 23:14   #54
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. . .
Quote:
Abstract

In a statistical description of ocean surface waves, the occurrence of extremely large waves is expected, but with low probability. In narrow-band, unidirectional waves it has been shown that the random-wave equivalent of the Benjamin-Feir instability results in an increased likelihood of extreme events (high kurtosis values) through near-resonant cubic interactions. Recent findings indicate however that freely developing directionally-spread waves do not develop such non-Gaussian features. Instead, the wave field returns to a near-Gaussian state, which is also what is invariably observed in field observations. . . .
Thank you Conachair, I knew my thinking was on the right track I just didn't have the right words to express it! It is most likely that the effects of medium inhomogeneities due to currents and topography on the nonlinear wave statistics supports a concomitant effect of refractive focusing and nonlinearity. The result being that narrow-band directionally spread waves can develop instabilities when traversing a refractive zone, resulting in local strongly non-Gaussian features (high kurtosis).

In other words, not all the time but sometimes, big BIG kerrrsplashy, and gurgle gurgle if you left the hatch open.
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Old 28-12-2010, 23:20   #55
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I hope this goes through.








I have been going to Sea for 31 years now. North Pacific and Bering Sea, I cannot honestly say I have seen a freak wave. I have seen plenty of big waves, but nothing double or more of the wave train.

Oh Jmolan, Jmolan, what a beauty! I have watched it heaps by myself and also watched it when I showed various family members. I know simple things amuse small minds, how else can I explain why I like it. Decades back I crossed Bass Strait (Aus) on the ferry, having purchased a cheap sit-up-all-night seat, I went to sleep on the floor under the seats and during the night woke as I was sliding to-and-fro across the floor. But nothing like the video. Hehehehe, it's great. Fancy trying to stop the piano from rolling back and forth!
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Old 28-12-2010, 23:32   #56
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Part of my dislike so much of conversations like rogue waves, somali pirates, and all that other jazz is that it sways people from caring about things that truly are important and that are not distant and minuscule threats. People spend more time worrying about rogue waves then they do their chainplates or cleaning out their diesel tanks.
Yup - and causes those we love and sail with to become unduly concerned - probably good stuff to tuck away - but keep the diesel polished and the rigging in EXCELLENT condition. Way better to be concerned about those things
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Old 29-12-2010, 06:23   #57
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Hmmm. At this point this thread is less than two days old. As far as I can see, there are a bit fewer than 41,000 registered members of this discussion board. It's reasonable to assume most of those people haven't looked at this thread in past two days. So this informal survey is sampling a relatively small group of people. But we already have several vivid, credible, first-hand accounts of encounters with these things.

They must not be that rare, really. I kind of wish I had never started reading. Thanks to those who have shared.

The last account sounds remarkably similar to the computer-generated freak wave in the movie "The Perfect Storm", which never seemed that realistic to me before. Yikes.
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Old 29-12-2010, 06:53   #58
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There was a cruise ship several years ago off the eastern US coast that took a rogue wave which damaged the upper decks. I think it put into Charleston, SC for repairs. Don't remember reading much about it.
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Old 29-12-2010, 06:56   #59
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I really don't like the word "Freak" or "Rogue" as suggests that extremely big (and scarey!) waves at inconveniant times are not to be expected at sea.

Not common is not the same as unexpected.

In my book coming down 5th Avenue would qualify as a Freak wave
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Old 29-12-2010, 07:17   #60
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With rogue waves, as with ANY weather related phenomenon, ones own personal experience is totally meaningless. Mine included! Only with scientific study, taking into account verifiable measuring devices, as well as hundreds of first hand stories relating rogue waves, both experienced and observed... only then does the big picture start to come into view. (Ignore what is related over drinks in a bar)!

As I have said earlier, if you read say... 500 articles on the subject, you realize that they are not so much HUGE and generated during a blow, (like in the movies), as the day or two after one, and it is assumed that it is when two separate wave trains combine into a few really large waves. It is often in a truly moderate sea, AFTER a storm is well over. Read the account of Gulf Streamer...

During the 21 full time years I spent building my boats, I kept going by reading literally thousands of books and magazines about this very sort of thing, among others. When it comes to weather related science, or any other science, one's own personal life experience is a drop in the bucket compared to the collective experience of tens of thousands of others, put together to look for the pattern.

Also, for decades rogue waves, that fit the definition, have been accurately measured with weather buoys. They are not necessarily huge, just twice the wave train. The notion that running into one is as unlikely as being hit by a meteorite is sheer folly. I would say it is much more likely than say... being hit by lightning. Lightning deaths are seldom reported worldwide, because it kills one or two at the time, nevertheless, it kills far more people than hurricanes.


The danger for mariners is more the "difference" in size than the "huge" size. It catches them off guard, with full sail up, and on autopilot. (perhaps pissing over the stern rail at night)?

If you spend say 10 years continuously at sea, you are quite likely to experience several rogue waves, and may not even know it. Forget "The Poseidon Adventure"... No one ever said that rogue waves suddenly flipping huge ships in a moderate sea, was anything but a movie!

On a sailboat, most waves that meet the definition... (like 16' in an 8' wave train), go unnoticed or are unremarkable enough to not get into a report of any kind.

Since there is no way to avoid or prepare for a rogue wave, (or hitting a container at night), the best we can do is: stand a good watch for shipping, and don't fall off of the boat.

Mark
Good points, but again I think it depends on your definition. If a "rogue" wave is only twice the size of the mean of the train, that shouldn't be uncommon at all.

http://www.mxak.org/weather/waves.pdf

If you received a marine weather forecast predicting “SEAS 10 FT” in the coastal or offshore waters, what is really being conveyed in that forecast?
• Hs = 10 ft
• H (mean) = 0.64 times Hs = 6.4 ft
• H (most probable) (slightly less that H mean) = 6 ft
• H1/10 (10% highest waves) = 1.27 times Hs = 12.7 ft
• H1/100 (1% highest waves) = 1.67 times Hs = 16.7 ft
• Hmax (highest wave you should be on the alert for) = approximately 2 times Hs = 20 ft!

But I'm not sure that's the correct definition of "rogue"
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