Rogue Waves

[Ladewig]

Read the links that I've posted. According to http://www.esa.int/esaCP/SEMOKQL26WD_index_0.html
[snip]
In February 1995 the cruiser liner Queen Elizabeth II met a 29-metre high rogue wave during a hurricane in the North Atlantic that Captain Ronald Warwick described as "a great wall of water… it looked as if we were going into the White Cliffs of Dover."

I'm a bit confused. What exactly is the definition of a rogue wave? If the wave is associated with a hurricane, then isn't it a hurricane-associated wave rather than a rogue wave? I'm not trying to be funny, I just thought that the original article was about exceptionally tall waves that occured with no observable explanation.

 

[Rodney]

Was there evidence back in the 80s or before that they are "not uncommon"?

Yes. Many reports from survivors of rogue waves, as well as damage to surviving ships.

What exactly is "not uncommon"?

Rogue waves are not uncommon -- at any given moment there are about 10 of them somewhere on the oceans of the world. It's still not known exactly how many ships those waves sink each year, but as Edward Willett states:

"In the last two decades more than 200 supertankers and container ships more than 200 metres long have been sunk by severe weather; rogue waves are believed to have been the cause of many of those losses."

"One cubic metre of water weighs one tonne. A storm wave 12 metres high hits a ship with a force of six tonnes per square metre. Ships are designed to take hits of 15 tonnes per square metre without damage, but a rogue wave, engineers estimate, could hammer a ship with 100 tonnes per square metre."

 

[Rodney]

I'm a bit confused. What exactly is the definition of a rogue wave? If the wave is associated with a hurricane, then isn't it a hurricane-associated wave rather than a rogue wave? I'm not trying to be funny, I just thought that the original article was about exceptionally tall waves that occured with no observable explanation.

According to Edward Willett:

"Rogue waves are monster, ship-smashing walls of water that rise to seemingly impossible heights, three to five times as high as the waves around them, and often come from unexpected directions."

" . . . Scientists and engineers have traditionally been skeptical about the reports of these monsters because the wave models they’ve been using for decades almost never produce a rogue wave. Statistically, according to those models, a rogue wave should arise only once every 10,000 years."

So, it would seem that the models that were generally used by oceanographers until the 1990s forecast that even hurricanes could not produce waves three to five times as high as the waves around them.

 

[Meffy]

"One cubic metre of water weighs one tonne. A storm wave 12 metres high hits a ship with a force of six tonnes per square metre. Ships are designed to take hits of 15 tonnes per square metre without damage, but a rogue wave, engineers estimate, could hammer a ship with 100 tonnes per square metre."

If this is true (I don't know how much of it is but for the sake of discussion let's assume it's all so), then how much heavier do you think ships would have to be made in order to have a satisfactory chance of surviving freak super-waves? Must every new oceangoing ship be six or seven times stronger? Can existing craft be retrofitted to achieve that kind of strength? That's going to cost a LOT. Who will pay the cost?

 

[Correa Neto]

I haven't done a compilation, but accounts of rogue waves have been around for centuries. ...snip...First, we know now that rogue waves are not uncommon. Second, why do you and so many other so-called skeptics always assume people are exaggerating or lying? Can you cite any studies that support this dark opinion of mankind?

Was there evidence back in the 80s or before that they are "not uncommon"?

And...
What exactly is "not uncommon"?

I've got a "dark opinion" on anedoctal data. And I am not the only one. If anedoctal data were reliable as you imly, fishermen tales would be something one can trust. On a serious line, why do you think eywitnesses are interrogated and their testimonies extensively checked (at least they are supposed to be) in court and whenever possible, backed by material evidence in court ?

We know now that rogue waves occur every day. So is it logical to assume that past reports of rogue waves were made up?

What we are discussiong here is if there were enough evidence favorable to their existence and if there were tools to study the phenomena before the 80s. It is utterly irrelevant to the present discussion if we nowdays know they may occur everyday.

Suppose back in the 60s, an oceanographer accepted a report of a giant wave. How would he/she study the phenomena? The reports would provide enough data for any study? The reports' areal distribution, time span, frequency, reliability, etc. may not be consistent enough! Think about it: the researcher may just come to the conclusion that the phenomena, assuming it exists, can not be probed with the avaliable tools. Just like in the asteroids example.

I did and found nothing of direct relevance. What's your point?

Check the Wikipedia entry for soliton. Look at the bottom of the page. You´ll see why.

Not a bad point (especially for you ). However, since insurance companies were until recently unaware of rogue waves (thanks to most oceanographers being asleep at the switch), there was probably a tendency to blame bad luck or incompetent crews for ships sinking.

Insurance companies blaming bad luck? Specially if shipwrecks that may be related to the phenomena are as common as you say? Oh, please...

And you are sure what was feasible? Can you document?

All it takes is a look at what tools were avaliable at each decade and you will be able to see what was feasible and what was not. I am pretty sure that such study was not feasible in the 70s, and quite possibly also not in the 80s. Remember (or ask to enyone who is 40+ years old) the computers that were avaliable back in the 80s or before. How would you, back in the 80s, gather and proccess data from a global network of buoys?

Check the solitons. Think about how would you study the phenomena without the tools we nowdays have.

What possibilities -- that ship crews were all exaggerating or lying and that tremendous damages to ships were all consistent with smaller waves?

Oversimplification of your part. "Tremendous damage" to ships may be inflicted by a number of causes during bad weather, not only by giant waves.

And your agenda is preventing you from seeing that there are many flavors of anecdotal data, and anecdotes from credible individuals frequently turn out to be accurate.

Rodney, exactly how many anedoctes from credible people on these giant waves were avaliable and what's their distribution and frequency in space and time?

ETA: Experienced connection problems...

 

[Rodney]

If this is true (I don't know how much of it is but for the sake of discussion let's assume it's all so), then how much heavier do you think ships would have to be made in order to have a satisfactory chance of surviving freak super-waves? Must every new oceangoing ship be six or seven times stronger? Can existing craft be retrofitted to achieve that kind of strength? That's going to cost a LOT. Who will pay the cost?

I don't think the focus is generally on retrofitting ships or building new ships to be able to withstand rogue waves. Rather, the focus is on improved forecasting to permit ships to avoid them.

 

[Meffy]

Fair enough. I don't know whether there will ever be forecasting good enough to predict them well though. Finer sensing will help some but chaos is chaos and computer models only go so far. I'm doubtful that there's much that can be done but whatever can, by all means I'm in favor.

 

[Rodney]

On a serious line, why do you think eywitnesses are interrogated and their testimonies extensively checked (at least they are supposed to be) in court and whenever possible, backed by material evidence in court ?

You're making my point. I have consistently argued that claims of eyewitnesses are not equal. Eyewitness A may say that something happened that Eyewitness B says did not happen. However, the number of witnesses and their credibility can determine with a high degree of probability what did happen. For example, if 10 respected citizens of a town tell essentially the same story, but the town drunk contradicts them, it's pretty likely that the ten have the story straight and the town drunk is wrong. If there is physical evidence that supports the ten and contradicts the town drunk, then it's almost certain that the ten have the story straight. Now, in the case of rogue waves, are there major differences of opinion among the eyewitnesses, with some saying that the wave wasn't significantly larger than surrounding waves? Not that I'm aware. Further, there are many eyewitnesses and physical evidence in most cases.

What we are discussiong here is if there were enough evidence favorable to their existence and if there were tools to study the phenomena before the 80s. It is utterly irrelevant to the present discussion if we nowdays know they may occur everyday.

Suppose back in the 60s, an oceanographer accepted a report of a giant wave. How would he/she study the phenomena? The reports would provide enough data for any study? The reports' areal distribution, time span, frequency, reliability, etc. may not be consistent enough! Think about it: the researcher may just come to the conclusion that the phenomena, assuming it exists, can not be probed with the avaliable tools. Just like in the asteroids example.

Again, the first thing an oceanographer in the 60s should have done is taken the reports of rogue waves seriously, rather than dismissing them. After determining that the reports were credible, (s)he should have performed as much research as technology would permit to determine how common they are and developed a mathematical model to account for them. No, that wouldn't have given us the level of knowledge that we now have about rogue waves, but it would have been a good start.

Check the Wikipedia entry for soliton. Look at the bottom of the page. You´ll see why.

Is your point that it took more than 100 years for the theory of solitons to be translated into practical reality, or rather that solitons may be related to rogue waves?

Insurance companies blaming bad luck? Specially if shipwrecks that may be related to the phenomena are as common as you say? Oh, please...

All I'm saying is that if insurance companies had known about rogue waves a generation ago, their rates may have better reflected the fact that certain routes are more vulnerable to those waves than other routes.

All it takes is a look at what tools were avaliable at each decade and you will be able to see what was feasible and what was not. I am pretty sure that such study was not feasible in the 70s, and quite possibly also not in the 80s. Remember (or ask to enyone who is 40+ years old) the computers that were avaliable back in the 80s or before. How would you, back in the 80s, gather and proccess data from a global network of buoys?

Again, there are uncertainties here, but don't you think it would have been a big step forward had an oceanographer in the 1980s come up with a mathematical model that accounted for rogue waves?

 

[politas]

Not according to the NY Times article or at least three others:

(1) http://www.esa.int/esaCP/SEMOKQL26WD_index_0.html "Once dismissed as a nautical myth, freakish ocean waves that rise as tall as ten-storey apartment blocks have been accepted as a leading cause of large ship sinkings."

"Once" dismissed. Not "previously dismissed". This statement says nothing about when rogue waves moved from being believed to be utter fabrication, to unusual events. They are still thought to be unusual events, just not quite as unusual as before.

(2) http://www.edwardwillett.com/Columns/roguewaves.htm "Scientists and engineers have traditionally been skeptical about the reports of these monsters because the wave models they’ve been using for decades almost never produce a rogue wave. Statistically, according to those models, a rogue wave should arise only once every 10,000 years. But that skepticism--and those models--have been demolished by recent data."

Hyperbole aside, being skeptical about reports does not equal dismissing the possibility. I am skeptical about the reports of Pat Robertson leg-pressing 2,000 pounds. That doesn't mean I think it is completely impossible for a human to do so, just that any particular report is unusual enough to require unusual levels of evidence.

(3) http://en.wikipedia.org/wiki/Freak_wave "Once thought to be only legendary, they are now known to be a natural ocean phenomenon, not rare, but rarely encountered."

See point 1. "Once thought" is not the same as "previously thought". Journalists are quite aware of the distinction, and always go for a comparison that sounds better.

Personally, I think it makes far more sense for oceanographers to study the many dangers at sea that are frequently encountered before looking into those that are rarely encountered.

 

[politas]

For example, if 10 respected citizens of a town tell essentially the same story, but the town drunk contradicts them, it's pretty likely that the ten have the story straight and the town drunk is wrong. If there is physical evidence that supports the ten and contradicts the town drunk, then it's almost certain that the ten have the story straight.

However, if ten solid respectable citizens make a claim, the town drunk contradicts them, and the physical evidence supports the drunk, then it's almost certain that the ten respectable citizens are possibly liable for conspiracy charges.

Physical evidence strongly overpowers anecdotal evidence. One scrap of DNA can overule 100 eyewitnesses.

Again, there are uncertainties here, but don't you think it would have been a big step forward had an oceanographer in the 1980s come up with a mathematical model that accounted for rogue waves?

Where do you think these mathematical models come from? Pure fancy? They come from examining data. A collection of anecdotes is not useful data, however much evidence it may be.

Without modern tools, infrastructure and computing power, there was no way to collect the necessary data to make a better model. They had to use what they had.

 

[Mojo]

Where do you think these mathematical models come from? Pure fancy? They come from examining data. A collection of anecdotes is not useful data, however much evidence it may be.

Well, if Cayce could just make stuff up, why can't oceanographers?

 

[Megalodon]

Again, there are uncertainties here, but don't you think it would have been a big step forward had an oceanographer in the 1980s come up with a mathematical model that accounted for rogue waves?

Of course it would have been a big step forward. And it would have been a big step forward if someone in the 60's would have developed cellphones and personal computers

It just wouldn't be possible. And you doubting it doesn't make it so.

In a fairytail world, where all the funding in oceanography was devoted to the exaustive study of rogue waves, it would still not be possible. This because of:

a) no data to put on such models;
b) no processing power to run said models.

I want to see your ultrage when you find out that plate tectonics was still being doubted by some geologists in the 80's

 

[Rodney]

Where do you think these mathematical models come from? Pure fancy? They come from examining data. A collection of anecdotes is not useful data, however much evidence it may be.

Without modern tools, infrastructure and computing power, there was no way to collect the necessary data to make a better model. They had to use what they had.

So the old model could not have been adjusted based on the knowledge that rogue waves occur on a regular basis? Even without better data, that model could have been experimented with by making some plausible assumptions and seeing if any combination of those assumptions produced rogue waves on a regular basis.

 

[Rodney]

Well, if Cayce could just make stuff up, why can't oceanographers?

And your evidence that Cayce made stuff up is . . .

 

[Rodney]

Originally Posted by Rodney :

Again, there are uncertainties here, but don't you think it would have been a big step forward had an oceanographer in the 1980s come up with a mathematical model that accounted for rogue waves?

Of course it would have been a big step forward. And it would have been a big step forward if someone in the 60's would have developed cellphones and personal computers

It just wouldn't be possible. And you doubting it doesn't make it so.

Mathematical models are based not only on data, but on assumptions, and so your analogy with developing cellphones and personal computers is flawed.

 

[Megalodon]

Originally Posted by Rodney :
Mathematical models are based not only on data, but on assumptions, and so your analogy with developing cellphones and personal computers is flawed.

You seem not to be able to get it. You need data in modelling! Desperatly! If you don't have data, then you cannot chose the appropriate parameters to include, or calibrate your results, which mean that they're worthless.

You cannot make predictive models without data.

If you base it on assumptions instead of data, is sci-fi, and can predict anything (and thus, nothing).

 

[MandosV]

Rodnay,
Please ... What is your point?
Hindsight is always 20/20. Monday morning quarterbacks always win.
If my aunt would have had testicles, she would have been my uncle.

Seriously, we wouldn't have used lead based paint if we knew that it caused damage to children. We wouldn't have used asbestos if we'd have known the damage it caused.

If you are simply pointing out that we were ignorant in the past, that's a specious argument. It is also a tautology.

If you are trying to argue that anecdotal evidence should cause us to drop everything, every time a new "phenomena" is observed, the posters here have disproven that quite nicely.

So, I ask again, what is your point?

 

[Correa Neto]

You're making my point. I have consistently argued that claims of eyewitnesses are not equal. Eyewitness A may say that something happened that Eyewitness B says did not happen. However, the number of witnesses and their credibility can determine with a high degree of probability what did happen. For example, if 10 respected citizens of a town tell essentially the same story, but the town drunk contradicts them, it's pretty likely that the ten have the story straight and the town drunk is wrong. If there is physical evidence that supports the ten and contradicts the town drunk, then it's almost certain that the ten have the story straight. Now, in the case of rogue waves, are there major differences of opinion among the eyewitnesses, with some saying that the wave wasn't significantly larger than surrounding waves? Not that I'm aware. Further, there are many eyewitnesses and physical evidence in most cases.

Ah, but where are the evidence that backs the claims?

Damage to the ships, you will say. But can you accurately link the damage to a giant waves at a signficant number of reports? No, not post-80s reports, you have to look to older reports, and they must be consistent.

Check what other posters wrote about the nature of anedoctal data x physical evidence. Note also that there must be a number of reports and damage possibly associated to the phenomena. One report that fullfils these criteria say, at each 10 years would indicate one of the following possibilities: (a) the phenomena is rare; (b) the damage was caused by unusually rough sea conditions, but not by a single monster wave.

Possibility (a) would bring severe problems to probe the phenomena, once you consider the avaliable technology and how vast are the ocean. You say 10 giant waves are crossing the oceans at any time. Try finding one, say, at the North Atlantic now. Now, how would you find one such wave in the oceans 20 or 30 years ago?

Again, the first thing an oceanographer in the 60s should have done is taken the reports of rogue waves seriously, rather than dismissing them. After determining that the reports were credible, (s)he should have performed as much research as technology would permit to determine how common they are and developed a mathematical model to account for them. No, that wouldn't have given us the level of knowledge that we now have about rogue waves, but it would have been a good start.

First of all, you can't really say they dismissed the reports.

Second, you just can't build a mathematical model out of the blue in real life. You will not just be adding wavelenght, speed and amplitude values to a simple wave equation. You must first gather enough data on the waves (again, how would you do that back in the 60s?) to allow a statistical study. No just on the waves themselves, but also on the sea and weather conditions where they were seen. Then you would start creating mathematical or physical models of the phenomena supposed to create the waves. Once its ready, you will enter the sea and weather data you gathered and check the outcome, making changes to the model as required by its output data.

Is your point that it took more than 100 years for the theory of solitons to be translated into practical reality, or rather that solitons may be related to rogue waves?

Solitons are one of the possibilities. Solitons, however, can happen in calm water. The point actually is that you can not really say that freak waves were ignored by science. You can look for them at lakes and channels (you probably followed the links and found a pic of one of them at a channel), but how would you find one in the open sea? See the similarities?

All I'm saying is that if insurance companies had known about rogue waves a generation ago, their rates may have better reflected the fact that certain routes are more vulnerable to those waves than other routes.

Insurance companies would for sure have noticed they wee paying for shipwrecks related to giant waves at certain sea lanes some decades ago if they were common enough.

Again, there are uncertainties here, but don't you think it would have been a big step forward had an oceanographer in the 1980s come up with a mathematical model that accounted for rogue waves?

See above. The construction of these models was at least very unlikely decades ago.

 

[Mojo]

And your evidence that Cayce made stuff up is . . .

http://www.straightdope.com/mailbag/mcayce.html

...we have several documented cases of Cayce advising how to cure dead people, in connection with readings using letters they sent to him. In these cases, the letters had been written while the person was still alive, but by the time he made his psychic "diagnosis," they were dead. Whoops! Of course, his followers have excuses for this type of thing, but it seems to me if he's getting his information through magical means, he should know this particular person is beyond help.

 

[Rodney]

You seem not to be able to get it. You need data in modelling! Desperatly! If you don't have data, then you cannot chose the appropriate parameters to include, or calibrate your results, which mean that they're worthless.

You cannot make predictive models without data.

If you base it on assumptions instead of data, is sci-fi, and can predict anything (and thus, nothing).

It appears that you have no experience with modelling. As Wikipedia -- http://en.wikipedia.org/wiki/Mathematical_model -- observes: "A mathematical model is an abstract model that uses mathematical language to describe the behaviour of a system . . . Mathematical modelling problems are often classified into black box or white box models, according to how much a priori information is available of the system. A black-box model is a system of which there is no a priori information available. A white-box model (also called glass box or clear box) is a system where all necessary information is available. Practically all systems are somewhere between the black-box and white-box models, so this concept only works as an intuitive guide for approach."