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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, @07:52PM

    by frojack (1554) on Sunday August 02 2015, @07:52PM (#217086) Journal

    No, it isn't.

    Not on any ship of size. The best you can do is warn everybody to grab something.
    Even automated watertight doors take longer to close than a minute, to say nothing about the manual doors.
    You can't turn a large ship in a minute. Something the size of a cruise ship might barely start responding to a full rudder input in a minute. Maybe.

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  • (Score: 2) by Runaway1956 on Sunday August 02 2015, @08:20PM

    by Runaway1956 (2926) Subscriber Badge on Sunday August 02 2015, @08:20PM (#217096) Journal

    I don't know anything about automated water tight doors - but I can state with certainty that a manually operated watertight door can be closed and dogged in about five seconds. If you're talking about doors large enough to drive a tractor through, well, maybe - but ships that large aren't especially threatened by rogue waves.

    • (Score: 2) by frojack on Sunday August 02 2015, @08:37PM

      by frojack (1554) on Sunday August 02 2015, @08:37PM (#217100) Journal

      If you have exactly ONE such door you might get it closed in 5 seconds if you happen to be standing right there when the alarm sounded.

      If you have even a pocket cruiser, you will have 20 such doors.

      On a ship the size of the Louis Magisrty referenced in TFS and TFA, which (according to YOU) should be immune to rogue waves (but clearly wasn't), you will have well in excess of a hundred scattered over 5 decks and you will not turn that ship in 60 seconds.

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      • (Score: 4, Insightful) by Runaway1956 on Sunday August 02 2015, @09:01PM

        by Runaway1956 (2926) Subscriber Badge on Sunday August 02 2015, @09:01PM (#217103) Journal

        Ahhh - it's a matter of playing the odds then. How big is big enough to ride a huge wave? And, which way are you facing when the warning comes? And how many doors are there to dog? And, how many crew are in positions to act?

        I insist that the larger the ship is, the safer the ship is. "Safer" being a relative term, of course. People who demand total safety don't go to sea, after all. They'll just remain sand crabs all of their lives.

        Since my life at sea was spent on destroyers, I am quite certain that sixty seconds warning can and will make the difference between foundering and survival for a destroyer. We drill, and drill, and drill - the standard is 3 minutes from peace time steaming to combat readiness. We cut the standard by 50% when we had reason to do so.

        Keep in mind that here, the ship doesn't have to achieve combat readiness - we are only concerned about watertight doors and hatches on the weatherdecks.

        Civilian ships don't have our training, and they certainly don't drill like mad men either. But, depending on all those vagaries already mentioned, one minute of warning that a rogue wave is bearing down on you, people who WOULD have died, might be saved.

        There is no cure-all solution possible. If you go to sea, your life is at risk. This warning system decreases the risk. That's good enough for me and the squids I've sailed with.

        • (Score: 3, Interesting) by fnj on Sunday August 02 2015, @11:59PM

          by fnj (1654) on Sunday August 02 2015, @11:59PM (#217158)

          It's not that simple. A comparatively tiny self-bailing lifeboat is probably "safer" than any size ship in the face of rogue waves. Coast guard boats and ships are also comparatively very small, but prodigiously seaworthy. I wouldn't give a plugged nickel for the chances of a grossly top-heavy container ship, even a gigantic one. And I'm pretty sure even a supercarrier could end up on her beam ends and in a very, very bad way.

          In Typhoon Cobra in 1944, several aircraft carriers suffered hangar deck fires due to planes careening around and crashing into bulkheads and each other. One carrier rolled 20 degrees, the edge of the flight deck practically lapping the surface. Battleship Iowa suffered a bent propeller shaft. Heavy cruiser Baltimore required major repairs. Three destroyers went down with a total of 775 men. In another typhoon in 1945, heavy cruiser Pittsburgh had her entire bow ripped clean off and left floating on its own.

          And these ships had HOURS to prepare for the lashing.

    • (Score: 0) by Anonymous Coward on Sunday August 02 2015, @09:25PM

      by Anonymous Coward on Sunday August 02 2015, @09:25PM (#217111)

      but ships that large aren't especially threatened by rogue waves.

      Evidently you never encountered one! 40 meters! Do you know how big that is in American? Many vessels would be pitch-poled by such a wave, and even a very large ship could be capsized.

      • (Score: 2) by tibman on Monday August 03 2015, @02:26PM

        by tibman (134) Subscriber Badge on Monday August 03 2015, @02:26PM (#217401)

        American sizes below one mile is the standard football field.

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  • (Score: 2) by skater on Monday August 03 2015, @12:09PM

    by skater (4342) on Monday August 03 2015, @12:09PM (#217361) Journal

    Modern cruise ships don't use rudders - they have "azipods" that can rotate 360 degrees and provide thrust in any direction. It's still not an instant turn, but it's a lot faster than the rudder era. But as others said, the other advantage would be giving time to get people away from the windows.