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posted by janrinok on Sunday August 02 2015, @06:47PM   Printer-friendly
from the hot-news-for-surfers dept.

"A device on the mast of a ship analysing the surface of the sea could perhaps give a minute's warning that a rogue wave is developing," said Professor Nail Akhmediev, leader of the research at the Research School of Physics and Engineering.

"Even seconds could be enough to save lives."

Rogue ocean waves develop apparently out of nowhere over the course of about a minute and grow to as much as 40 metres in height before disappearing as quickly as they appeared. Ships unlucky enough to be where rogue waves appear can capsize or be seriously damaged, as happened in the Mediterranean Sea to the Cypriot ship Louis Majesty, which was struck by a rogue wave in 2010 that left two passengers dead and fourteen injured.

The research by Professor Akhmediev and the team at the ANU Research School of Physics and Engineering, Dr Adrian Ankiewich and PhD student Amdad Chowdury, is published in Proceedings of Royal Society A. Professor Akhmediev said that there are about 10 rogue waves in the world's oceans at any moment. "Data from buoys and satellites around the world is already being collected and analysed. Combined with observations of the surrounding ocean from the ship this would give enough information to predict rogue waves," said Professor Akhmediev.

The theory may also explain freak waves that wash away people from beaches, as the rogue waves can sometimes transform into travelling waves known as solitons, that travel through the ocean like mini-tsunamis until they hit the coastline.

Professor Akhmediev's theory also applies to other chaotic phenomena such as light travelling in optical fibres, atoms trapped in a Bose-Einstein condensate and the ionosphere in the upper atmosphere. The rogue wave is a special solution of the non-linear Schrodinger equation which is localised in time and space. The solutions were derived by adding terms to cover dispersion to the non-linear Schrodinger equation, forming the Hirota equations.


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  • (Score: 2) by frojack on Sunday August 02 2015, @08:27PM

    by frojack (1554) on Sunday August 02 2015, @08:27PM (#217098) Journal

    A minute is more than sufficient time for almost any ship to come about on a new heading.

    Utter bullshit. Have you been on anything bigger than 30 feet?

    Here is a Rate of Turn indicator [marine-data.co.uk] for a medium sized boat (maybe up to 150 tons). Notice it reads out in degrees per minute, and the scale only runs to 30 degrees. So at maximum rate of turn, with the meter pegged, you would be a third of the way through your turn and heeled over in EXACTLY the wrong direction at the end of your minute. You've just set your ship up for a roll over.

    Typical turning rates for merchant vessels is .5 to 1 degree per second for lightly loaded vessels.
    Certain naval Frigates, designed for tight turns of anti-submarine work have achieved 3 degrees per [youtube.com] second (at far less than full speed).

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  • (Score: 5, Insightful) by Runaway1956 on Sunday August 02 2015, @09:14PM

    by Runaway1956 (2926) Subscriber Badge on Sunday August 02 2015, @09:14PM (#217106) Journal

    How far do you need to turn? Never more than 90 degrees. If the rogue is coming at you directly from port or starboard, then you need to turn 90 degrees, right? What about when the wave is coming at you from a relative bearing of 270? You only need turn 30 degrees to meet it head on. Or, it's coming at you from 210 relative? Again, you only need come about 30 degrees to present your stern to the wave.

    And, yes - I've already stated that I LIVED aboard destroyers for five years. Considerably larger than a 30 foot boat.

    http://www.navsource.org/archives/05/01023.htm [navsource.org]
    http://navysite.de/ff/ff1049.htm [navysite.de]

    I've already stated that a merchant ship will probably benefit from this warning less than the Naval ships I am accustomed to. That doesn't mean that they can't benefit at all. At the least, those sailors can get inside and dog down the door they used to get inside. And - if they can turn only three, five, or ten degrees before the wave strikes, their odds of survival have increased by that much.

    Why are you spending time arguing that the warning is worthless? Warnings always have value. How much value depends entirely on the immediate circumstances that you find yourself in. The warning system will save some lives - but it's not going to save every life.

    • (Score: 2) by fnj on Sunday August 02 2015, @11:34PM

      by fnj (1654) on Sunday August 02 2015, @11:34PM (#217149)

      How far do you need to turn? Never more than 90 degrees.

      Even as a landlubber I cannot stand avast.

      If you're not too keen on taking a huge wave over the transom, you might have to turn 180.

      Finally, face it, in picking a destroyer for your reference point, you've picked about the most maneuverable ship there is. There are not all that many destroyers sailing the seven seas. Not compared to the vast number of cruise ships and grossly top heavy container ships. These others do not have anywhere near the number of seamen hanging around ready to respond to orders to dog the watertight hatches, as destroyers do (which in turn are far inferior to WW2 crew count, for that matter).