Jul

31

 Anything of relevance?: "Rogue Wave Theory to Save Ships"

Stef Estebiza writes: 

Better than "of relevance", it is fundamental. The wave is only the visible part of the situation: "Artificial Surfing Reefs".

Pitt T. Maner III adds: 

Have you seen this video of a rogue wave hitting a tanker? The video is not, by any stretch, a rogue wave though. Those are large enough that their weight simply breaks the ship's steel.

Here is a picture of the damage from a rogue wave to Hornet from WW 2.

Steve Ellison responds: 

Yes, in the markets too there are infrequent "rogue waves" that can be catastrophic. A recent example was the move in the Swiss franc after the Swiss central bank abandoned the peg to the euro. If one is using leverage, such a rogue wave can easily be fatal.

The study of earthquake recurrences might also be fruitful. There was recently some media attention to the possibility of a magnitude 9 earthquake in the US northwest that would have many characteristics of the Japan earthquake in 2011, including elevation changes that would put some areas below sea level and drop others to within range of a tsunami. Such an event could occur tomorrow or might not occur until a later century.

Jim Sogi writes: 

A rogue wave can be a "hole" in the ocean due to random overlapping of normal size waves. Sometimes a hole forms big enough for the ship to drop into the ocean, and get covered up. The waves are not always "high" waves.

In the market, random and other forces can cause big air drops, or a no bid situation. I think these are the ones most damaging to traders. It's not just the big climax peaks.


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  1. Michel Olagnon on August 4, 2015 8:23 am

    Rogue waves can be defined in many ways, yet the one I prefer is “a wave of extreme severity that appears unexpected even to an expert”. Given that definition, rogue waves do exist, yet there is no evidence that they would be globally more frequent than conventional (non-linear) waves theories predict, they just don’t happen where and when — i.e. in the most extreme sea states — one would expect them.

    There is no evidence either that the “modulational instability” theory that my colleague Prof. Akhmediev puts forward to explain them would not apply: the theory was validated in wave tanks, optical fibers and plasmas. It is just impossible to know whether the necessary boundary conditions are satisfied in nature.

    Several points may be noteworthy to the Specs:
    1. A recent article http://arxiv.org/abs/1503.00706 shows that rogue events can be empirically predictable, but that for ocean waves the delay would be of the order of the time needed to shout “Buddies, grab something and hold on to it !”
    2. “Normal” extremes are at least as frequent as “special” ones, and all indicators based on breather theories such as Akhmediev’s have false alarm rates of at least 90%, perhaps 99%, and still fail to warn of about 10% of actual rogue waves.
    3. Experienced sailors deny having met “rogue waves”. They say that they encountered waves that were rogue, they capsized or broke some ribs (Roger Taylor, http://www.thesimplesailor.com/voyages.html, Isabelle Autissier, https://en.wikipedia.org/wiki/Isabelle_Autissier), but when you discuss it directly with them, nothing that they were not expecting and had not prepared their ship for.
    4. Only a very small percentage of fatalities occur well off the coast (Nikolkina & Didenkulova, http://www.nat-hazards-earth-syst-sci.net/11/2913/2011/nhess-11-2913-2011.html), most of them happen at the coast or in shallow waters where victims feel wrongly on safe ground or in safe waters.

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