Rogue Waves ... Again

[conachair]

Rogue wave recreated in laboratory tank

Using one solution to the non-linear Schroedinger equation

Of course, should have thought of that...

A bit more sensational is a youtube in the comments

YouTube - ‪Rogue Wave Full Version XVID‬‏

[ADMPRTR]

I have seen on several occasions where a wave, every once in a while, is considerably larger than it's peers. It appears simply the combination of two or more waves that have differnent periods.

As a result, rogue waves always seemed possilble to my mind (I guess it all depends on one's definition of "Rogue") but then I have only dealt with smaller inland waves which have a very different physics than open ocean waves.

But then, I am not a scientist...

[capn_billl]

The mathematics of waves follow interference patterns, and so can either add or subtract depending on phase, also waves can be focused by surrounding ocean floor terrain, I.e wedged shaped underwater canyons, and mountains can act as lenses to increas wave heights. Also waves can stack with an opposing wind or if two storms collide as in the "perfect storm". Also extremely long period waves like thoses generated by tsunami's and hurricanes can get very steep and high as they go from deep water to the continental shelf.

In short they have been well documented to exist, the physics are there to explain them. Stay well away from possible wave traps, were two land masses converge, or under water mountains, during severe weather that can generate long period waves.

[mikereed100]

Shouldn't we, in these politically correct times, be referring to these as "special" waves rather than "rogue" or "freak"?

[btrayfors]

Not only do they exist, but they're more frequent than thought. Satellite imagery confirms this.

And, they are DANGEROUS. One very recent incident caused the loss of a 45' cruising boat enroute from Florida to Greece, about 100 miles off the coast of Nantucket. This very experienced cruising couple were very lucky!

Noonsite: USA: Rogue Wave Swamps Cruising Yacht off East Coast

Bill

[hummingway]

They say it ain't the meat it's the motion. Rogue waves are said to be very steep and, as in the video, your boat won't climb them; dangerous indeed.

[MarkJ]

Originally Posted by btrayfors

And, they are DANGEROUS. One very recent incident caused the loss of a 45' cruising boat enroute from Florida to Greece, about 100 miles off the coast of Nantucket. Bill

Yes, they can be dangerous, but my opinion is that ONLY in the wrong season or in just a few places in the world.

Those being wind agaist Agulas current, Bay of Biscay at the continental shelf of the UK, anywhere in the Southern ocean in winter, and the Gulf Stream in a storm.

Now Bills example from Noonsite... theres obviously an error somewher as one doesnt go to Greece from Florida via Nantucket!

120 miles southeast of the coast of Nantucket, Massachusetts, when a rogue wave hit ......
were sailing their 45ft boat from Florida to Greece

Now if you run a line from nantucket 100nm or 120, south east what do you find?

In 10 miles the ocean comes up from 2,500 meters to just 109 meters.

Not only that you have a whoel lot of weird underwater canyons....

and doesn't the gulf stream come in close there?

So yes, rouge waves are about.... but only in some few places and in the 'wrong' season or conditions.

Maybe someone with local knowledge can tell me?


Mark

[boatman61]

LOL... I thought that was a bit of a roundabout way to Greece.... unless they were planning the N route via Iceland, etc....
Also I would tend to agree with Mark as to specific areas/conditions rather than a global phenonema... and I mean rouge waves... not earthquake/hurricane induced effects... I have been dumped on N of Bermuda in the N Wall.... not nice.. punched out a bulkhead in the forecabin and all I could see through the deck hatch overhead was water... I've experienced 'wave smack' loadsa times but this was something different.. I thought we'd been rammed and the seas were not that big.. just strong wind F8ish and I was being lazy down below.. rouge wave... dunno...
But it freaked me enough to turn back to check the boat over for more damage...
still had 2.5K or so to go...
Get some wierd stuff in the Biscay as well in SE gales... I've seen waves coming vertically straight up out of the water... in complete opposition to the pattern... wind gets severe enough they all start going vertical... as a friend of mine described it... like a bowl of custard standing on a washing machine at full spin... on a massive scale.. you go up and fall of the top...

[sailronin]

Van Dorn's "Oceanography and Seamanship" goes into a pretty explanation of constructive interference and "rogue" wave development. A couple of nomographs that relate wind speed, fetch and probability of wave height being anywhere from 2 to 10 times the mean wave height.