Roque Waves

[MicHughV]

There was a topic on this forum a while back regarding roque waves and I have been bopping around Youtube and found this, which seems to support my theory that a roque wave is a wave climbing on the back of another.

https://www.youtube.com/watch?v=rK9aKFI2fA8

[Love2 boat]

Is it not funny that you find what you look for? :-)

[MicHughV]

Kinda sorta.

I'm a structural marine engineer by profession, so these types of things interest me.
As such, I have been involved in computer generated wave modelling to address various and sundry projects I have been involved with.

[wholybee]

I don't think there is any doubt that rogue wave are the result of smaller waves adding. It is the chaotic nature that is less understood.

If you play a note on an instrument, then add a second, very close in frequency to the first, you can hear the beat between them. That is the additive property of waves, creating a 3rd wave pattern. As you add more notes, the patterns become more complex, but still regular.

Now, imagine enough notes, with just the right frequencies, that if you listen to them for hours, to what seemed like a relatively constant volume and tone, all of the sudden there is a very loud boom where they all lined up just so, and then it goes back to the relatively constant tone again.

I think that is a decent analogy of a rogue wave. Ultimately, it is just the adding of waves. But, there are enough waves of different frequencies interacting that very rarely they add up in an unpredictable way, never to happen again.

[GordMay]

Originally Posted by wholybee

I don't think there is any doubt that rogue wave are the result of smaller waves adding. It is the chaotic nature that is less understood...

Indeed.
Oceanic winds & current, and bathymetry [probably] also play a significant role, in freak wave formation.

According to Professor Akhmediev, of the ANU Research School of Physics and Engineering,
“There are about 10 rogue waves, somewhere, in the world's oceans, at any given moment.”

In spite of significant theoretical, numerical, and experimental progress, there is no real consensus on exactly how rogue waves form.
So, while the mechanisms of rogue wave formation remain disputed, there are two main [competing] schools of thought:
* Linear interference [dispersive focusing, or superimposition, where 1 = 1 = 2] suggests they come from smaller waves, simply combining, and piling up,
* Non-linear phenomena [Schrödinger mechanism & Benjamin-Feir instability, where 1 + 1 ≈ ±3] proposes that variations in wave shapes amplify height differences exponentially.

Manuel A. Andrade explains [beyond my understanding] both, mathematically, in:
“Physical mechanisms of the Rogue Wave phenomenon”
➥ https://math.arizona.edu/~gabitov/te...es_Midterm.pdf

[GordMay]

How the World Largest Container Ships Survive Intense Waves, Without Breaking
➥ https://www.linkedin.com/pulse/how-d...-shipsgo-px3sc

If you prefer Videos, to reading, see these:

➥ https://youtu.be/wsjo0Lf34rg

➥ https://youtu.be/e5KI5NJvHK0

➥ https://youtu.be/SkA8680zTzE

[CaptainRivet]

I got hit by pyramid rogue wave approx 8-10m high (2nd spreader on a 17m mast) upfront Graciosa/canary island. We had waves from 3 direction, out on the ocean was a storm so from west through the channel between Graciosa and Lanzarote around 3-4m partly breaking, from NW around Nordtip of Graciosa the same and NE down from Algarve . Wind around 30-35kn.
Was steering manual zigzag with both engines so I got each wave around 30 til 40 degrees over. Suddenly behind a NE one I saw a huge wave coming up straight upfront the bow formed like a pyramid and waves from 3 direction stopped for a short time…all 3 waves where synced to one big one that was like a pyramid, I slamed both engine into WOT (have 2x50hp instead 2x20hp which saved the cat) to avoid the peak of it and go in an angle over the side…I managed to go nearly fully over it and was with one bow already over the top of the sidewall when the top collapsed/broke and got onto BB bow which was partly in the air while the STB one was still fully in the water and then onto foredeck but then over side upfront the deckhouse…was really lucky to be heavily overmotorized otherwise I wouldn’t have come that high onto the wave. But that slam was enough that the cat got so twisted that all glued stringer and bulkheads detached from the hulls…I just discovered that a week later as beside the Big Bang, some broken cutlery and the microwave broke loose flying down the stairs I couldn’t immediately after find some damage.
A 55ft mono that was maybe 50m behind me and had no chance when the top of the pyramid wave crashed over and swiped the complete deck and gave it a 360 rollover. Crew of it was thanks got inside and beside cuts and a broken wrist/leg was thanks got unharmed.
Was just one pyramid rogue wave, afterwards the normal waves from 3 directions continued. Pyramid rogue Wave was also visible on the webcam of orzola/lanzarote that’s faced out to ocean from their habour.
I towed the mono into closeby Graciosa Harbour as coastguard was busy and to far away assisted by a fishing trawler from the Harbour.
A week later I got a bottle of redwine from the BB forward bilge and when I lifted the floorboard the 3 forward stringers were lying next to each other loose in the bilge, they broke clean of the hull as the twist was bigger that the porcelain hard glue that Fountaine Pajot uses couldn‘t flex with. As the surveyor then found all stringers and bulkheads were detached from the hull, basically the whole spine of the cat was broken and only hull itself was holding it together. Repair 9 month and all laminated in now with epoxy plus 3 half bulkheads and 3 stringers additionally per hull to re-enforce everything. Better then new now.
As I had the other captain of the mono witness the pyramid wave and saw it happen plus a recording of the webcam showing the wave the insurance declared coverage immediately as cause of damage was clear.

[kmacdonald]

I think I'll puke the next time I hear someone say they got hit with a rogue wave.

[massnspace]

No such thing as a “rogue” wave.

Waves do not have freewill. They simply obey the laws of particle physics. Some are bigger and some are smaller, but none have “gone rogue”.

Fun to think about and discuss, but that doesn’t change basic physics….

[PippaB]

Originally Posted by massnspace

No such thing as a “rogue” wave.

Waves do not have freewill. They simply obey the laws of particle physics. Some are bigger and some are smaller, but none have “gone rogue”.

Fun to think about and discuss, but that doesn’t change basic physics….

Don't need freewill. As an adjective, rogue is defined:

Large, destructive, and anomalous or unpredictable.

behaving in ways that are not expected or not normal, often in a way that causes damage 1

A rogue element is someone or something that behaves differently from others of its kind, often causing damage. 2

unusually large, unpredictable, and destructive 3

Aberrant, anomalous; misplaced, occurring (esp. in isolation) at an unexpected place or time. 4

[massnspace]

Originally Posted by PippaB

Don't need freewill. As an adjective, rogue is defined:

Thanks for proving my point…..

If it is defined as “unpredictable”, that shows some type of agency.

Nothing is unpredictable in the world of particle physics….nothing.

All motion of (non-thinking) objects are governed by well-defined and well-understood laws of motion….

[kmacdonald]

Sea buoy data suggests that rogue waves are so infrequent that they can safely be completely ignored. You might think you were hit by one but the odds are better you were hit by an ET. Set the autopilot and go below for some sleep when you have delusions of being hit by a rogue wave.

[kmacdonald]

Ocean wave vary in size quite a bit. The bigger ones are not "rogue". They are just bigger. For instance, 34 to 40 kt wind will build waves to about 12 to 16 feet. It wouldn't be unusual to see some 20 to 24 footers mixed in. Those would not be dangerous or breaking waves at that wind speed. There would be white caps but don't confuse that with breaking waves. Breaking waves in deep water requires major hurricane force winds. No one survives breaking waves in a pleasure boat.

[Don C L]

A computer model showing waves, going the same direction, of different frequencies, will certainly show waves pile up on each other eventually. But in real life I am more interested in seeing models showing waves from different angles, as CaptRivet references, and whether or not they are breaking, which will likely result from current and wind effects. Didn't we have a thread about rogue waves generated around areas of current convergences a few years back? Those were more that 2X the average wave height as I recall.

[kmacdonald]

I think wind against current was one of the hypotheses regarding rogue waves. I didn't think it got much traction but steep waves produced by wind against current is well known and understood. Not as dangerous as one is led to believe but it makes for very uncomfortable conditions.