Rogue waves

One or two container ships per year lost to rogue waves would not have a significant impact on the amount of plastic in the (at least four) ocean gyres.

 

They and all the other lost at sea ships carrying cargos certainly do add to it.

A check of the losses reported each year to L of London is a eye opener. They only list their casualities. Not all the sinkings. Many countries do not record & release bad news. Bad for hiring crews & tourism.

The positive spin on it is, the stuff is settling to the bottom in a natural dead zone.

So all governments call in favors of major news media to not spend time on it.

Notice the extremely positive & endless commericials from the oil & coal industry companies? Latest spin is the great oilsands in Canada. Will that lower the price of

I wander. Disregard the last 2 paragraphs.

 

That's still a minor contribution compared to the amount entering oceans because of filthy industrial practices, illegal dumping, detritus thrown from ships, people's littering habits etc.
Claiming that rogue waves sinking a couple of ships per year is a major cause of marine pollution lets the real perpetrators off the hook.

 

I will buy that.

The total junk washed into the oceans by tornadoes, hurricanes & people / companies shoving junk into rivers at night & high water levels around the world is massive. Rivers have ALWAYS been the cheapest garbage disposal system.

 

I'm not sure if it was the same storm or even the same wave mentioned in this video, but it was around that time so it probably was. I came back from leave to the Brent Bravo platform and was told about massive wave damage to the platform Cellar Deck on the North face, 80 to 90 ft above the sea. Steel walkways and bulkheads were severely damaged. The platform was a concrete gravity base Condeep design with three legs and the steel deck and superstructure on top. The Northern leg was the Utility shaft and the drilling casings went down the other two.

People who were on the platform said it felt like the North end of the platform had been raised up and crashed back down. Everybody assumed this was an exageration, but when we were doing our inspections below the deck after we got scaffolding in place, we found that a large export riser (pipeline) that had an S-bend in it was sitting over an inch clear of it's support. I spent some of my apprenticeship on large-bore pipe bending and it looked to me like the bends had been sprung open and resettled in a new position.

http://www.youtube.com/watch?v=sCxr_XzyGO8&feature=related

 

Guess The off shore design engineers saved a TON of money by hanging stuff underneath.

" No such thing as a 100' wave anywhere. " " See. It says that right here in this book & reference material I decided to use as proof. "




Did I do good Boss ??

Real good son. Real good.

 

Not the case. The reference materials for that platform WOULD have included a 100 foot wave.

As JE Hardiman says in posts above, waves of that kind of height have been known of and specified for more than 60 years. Especially in offshore design. A 30m (98 feet) has been the pretty standard "design wave" in the northern North Sea since people started putting platforms there.

In this particular case, the question is more like - should the design wave height be 35m instead of 30m, or should wave impact be tolerated in the design - or the design made to avoid ANY wave impact (over a period of 100 years or 1000 years or whatever) ? Or how much wave run-up the sides of the concrete columns should be expected ?

In the open ocean where bigger waves can be expected, the oiler USS Ramapo reliably measured a wave of 112 feet as long ago as 1933, which was reported at the time and re-published many times since. Does not make for good TV I guess.

 

Now now.

Must not panic EVERYONE in the shipping industry.

Keep discrediting the facts as EXTREMLY rare occurances. That has worked for hundreds of years. We will also make sure the severly damaged ships & missing ships are deleted in all news coverages.

We have to find out who is leaking out the Loyds of London Rouge damage reports. That information is very damaging to the design industry.


" Boss. Is it OK if we made simple long skinny underwater submarines to transport stuff ? "

" NAAAHH. We have got everything running acceptably well right now. Very good solution to a big problem. But nobody wants to change anything anymore. "

 

A decade and a half on, new work.

'Rogue waves' can be 65 feet tall, but they aren't 'freak occurrences,' data from North Sea reveals https://www.livescience.com/planet-earth/rivers-oceans/rogue-waves-can-be-65-feet-tall-but-they-arent-freak-occurrences-data-from-north-sea-reveals

 

We are getting in the realm of conspiracy theories. Do you have any data to prove your point?

 

It's been 9 years since @cyclops2 was last seen, so almost certainly wacked by the Deep State.

 

Holy cow! It turns out it was constructive intereference, which was excruciatingly obvious to me the first moment I heard of them, when I was 17.

 

LOL....

 

NOTE: I'm not an expert, and my explanations may be all wrong.

A few decades ago I read an oceanographic book about waves in connection with work - we were measuring significant waveheights using RADAR and LIDAR from an aircraft and satellite. The book indicated that the highest waves (they mentioned an at least 113' example measured by a U.S. Navy ship) were "convergence waves" - what the earlier article linked to by jehardimanin called "constructive interference" - essentially where two or more waves come together to sort-of add. (Big waves are non-linear, and maybe the biggest more or less destroy themselves by wasting energy, by tossing part of the wave into the air? I'm not sure I have that right. Maybe very big waves just tend to spread out until they are no longer very big, if they aren't part of a wave train with similar height neighboring waves. Regardless they don't truly "add" in a linear sense.)

(Interestingly, there was at one point an attempt to take advantage of very big wave's tendency to destroy themselves. They wanted to use nuclear explosions to stop tidal waves. I think the idea was that an outgoing wave created by the explosion would interact with the incoming wave in such a way that all the energy would be wasted. AFAIK, the research was terminated. Perhaps they were worried that too much was unpredictable - part of the outgoing wave might affect someone else's shores, or that there was no way to get the required data in time. Perhaps they worried a bad actor would collect the nuclear devices and use them for nefarious purposes. Or perhaps they classified the results, and we have nuclear devices covertly placed to stop catastrophic waves near big cities on U.S. shores. Conspiracy theories are so much fun! A shame most of them are nonsense.)

At least at that time, tsunami hadn't been measured quite that high, but there are theories that some might have been higher in the past as a result of volcanic eruptions or other severe earthquakes.

Also theory held that if a glacier calves into a bay that is largely sealed off by sea ice, the confined wave could be about 300' high. And there was a recent example (maybe in Alaska??) where a glacier calved into a river with twists and turns that likewise confined the movement of the water, where I seem to remember it got even higher.

I assume an asteroid impact on the ocean could at least locally produce a very high wave.

And there are speculations that when the moon was new (and much closer to the Earth than it is now), tides were maybe a couple miles high in some places. But I'm not sure if that is a "wave" in the conventional sense.

But if I understand correctly, "rogue waves" are generally believed to be different than the any of these, or results you would expect from random noise, or random convergence of other waves. I think the theory is that if one wind driven wave starts out well above the others in a wave train, it catches more of the wind, and keeps growing more rapidly than the others. (Maybe it even casts a wind shadow on the other local waves, slowing their growth?) I do not know if there is well established physics for how that one wave starts out much higher than its neighbors. The link the other person gave suggests there is - but I don't trust anything that uses AI that way. To be more plausible, I'd want to see a deterministic model.

This means that the encountering such a wave is not predictable based on observable (from a ship) sea conditions. Most of the time, the waveheights you see at sea are relatively consistent, in the sense that wave trains are largely composed of waves of about the same heights, though it gets a bit complicated in regions where waves come at you from several directions. So it is kind of a rogue event, well outside what a sailor might reasonably predict by observing the local sea conditions.

That is very different from the idea of an ordinary "statistical outlier", in the sense that I think (this may be wrong) you can't model how likely it is to occur based on measuring the statistical properties of the wave heights before you encounter the rogue itself. Because the distribution of waveheights (if you use large enough waveheight bins) would be relatively smooth, except for that one extreme wave, which stands well above all the other measured waves.

Of course, if you looked at all the rogue waves that occur over the course of decades, maybe they do have a reasonably shaped statistical distribution, though I'm not sure. Anyway, that wouldn't help sailors figure out when they need to evacuate an area to avoid a particular rogue wave.

Now, if the AI model could predict that, it would be useful. But as best I understand the link, the prediction of individual rogue waves isn't claimed.

If I got that all right, I hope it answers your question.

 

A little bit of right, a little bit of wrong....

For a full discussion of your thoughts we would need to seperate "large" "waves" into three distinct types; impluse, breakers, and "statisticly significant" and discuss how and where each is formed and dissapated. While I could wax pedantic like an Oxford don, I doubt that many would care to read through an hour long Oceanography lecture, so I direct you back to Wiegel mentioned earlier.

Suffice to say that at any time in any one square mile of ocean, there is a single event "wave" that is 4-6 times the height of the average waveform in the area. In order to observe that specific "wave" you must be co-located and co-temporal (satellite LIDAR area sampling doesn't count) which is why very few are reported.