This is interesting, from AALTO UNIVERSITY:
The 260-meter long German barge carrier MS München was lost mysteriously at sea in 1978. The final communication message was a garbled mayday message sent from the mid-Atlantic. Afterwards, only a few bits of wreckage were found, including an unlaunched lifeboat. The most accepted theory is that one or more rogue waves hit the MS München and damaged her.
Rogue waves – also called freak waves – are unusually large surface waves that occur in the ocean. People have usually reported them as having appeared suddenly or without warning, sometimes with tremendous force. A researcher from Aalto University has now learned how they may appear in realistic oceanic conditions.
Video: Potentially extremely dangerous realistic rogue waves can now be controlled and generated at will in laboratory environments. CREDITVisa Noronen, Amin Chabchoub, Sebastian Roede
– Potentially extremely dangerous realistic rogue waves can now be controlled and generated at will in laboratory environments, in similar conditions as they appear in the ocean. This will help us not only to predict oceanic extreme events, but also in the design of safer ships and offshore rigs. In fact, newly designed vessels and rig model prototypes can be tested to encounter in a small scale, before they are built, realistic extreme ocean waves. Therefore, initial plans may change, if models are not resistant enough to face suddenly occurring freak waves, says Professor Amin Chabchoub from Aalto University.
The birth of rogue waves can be physically explained through the modulation instability of water waves. In mathematical terms, this phenomenon can be described through exact solutions of the nonlinear Schrödinger equation, also referred to as “breathers”.
For a couple of years, the research team around Professor Chabchoub has already been able to create steered rogue waves in laboratory wave flumes. However, this has only succeeded in perfect regular wave conditions. In nature, this is rarely the case.
The article has been published today in Physical Review Letters.
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From NOAA:
Rogue, freak, or killer waves have been part of marine folklore for centuries, but have only been accepted as a real phenomenon by scientists over the past few decades.
Rogues, called ‘extreme storm waves’ by scientists, are those waves which are greater than twice the size of surrounding waves, are very unpredictable, and often come unexpectedly from directions other than prevailing wind and waves.
Most reports of extreme storm waves say they look like “walls of water.” They are often steep-sided with unusually deep troughs.
Since these waves are uncommon, measurements and analysis of this phenomenom is extremely rare. Exactly how and when rogue waves form is still under investigation, but there are several known causes:
Constructive interference. Extreme waves often form because swells, while traveling across the ocean, do so at different speeds and directions. As these swells pass through one another, their crests, troughs, and lengths sometimes coincide and reinforce each other. This process can form unusually large, towering waves that quickly disappear. If the swells are travelling in the same direction, these mountainous waves may last for several minutes before subsiding.
Focusing of wave energy. When waves formed by a storm develop in a water current against the normal wave direction, an interaction can take place which results in a shortening of the wave frequency. This can cause the waves to dynamically join together, forming very big ‘rogue’ waves. The currents where these are sometimes seen are the Gulf Stream and Agulhas current. Extreme waves developed in this fashion tend to be longer lived.
Proper science that can save lives and actually improve things.
About as far removed from climatism as you can get :L-)
I was on a ship that got hit by a rogue wave; well it was a tsunami wave.
Sometime between Feb 16 1961 and march 13 1961 out in the Pacific Ocean somewhere. The Captain said it was coming at us at 400 mph, and he would toot the horn just before we got hit.
So naturally we all lined the ships rails to wait for the horn to toot. I had my 8 mm movie camera ready to record it.
So the horn tooted, and the wave came and went and nobody saw a thing. The wavelength was about 150 miles, and it was about one foot in height.
But as I recall, it did a lot of damage when it went up some river in Australia.
No Poseidon adventure for me.
G
Cool. the idea of constructive interference is pretty obvous cause, but it’s nice being able to reporduce it.
Now just apply the same idea to the thermocline you will have the trigger for El Nion events. 😉
Oops, El Nino.
What I mean is that any surface between different density media can have waves. The density difference at the top of the thermocline is about 1000 times smaller that at the surface so the waves will typically be about 1000 times slower.
In fact I suspect that thermocline movement is slow tidal movement but the addition of constructive interference will give similar ‘rogue’ waves from time to time. IMO this is what is typically described as temperature ‘anomalies’ at a certain depth. It is not that the water is warming and cooling it is horizontal movement of water moving heat around. This happens in all directions, not just east-west. The usual equatorial sections are misleading since they give the false impression heat is appearing and disappearing.
I’ve seen a demonstration of a wave travelling along the boundary between water layers of different densities. It was used to show how unusual waves can form on Loch Ness and how their appearance can resemble the wake of something moving just below the surface and hence generate many monster sightings.
It is jaw dropping when it happens. I was baiter on a commercial salmon boat off the northern California coast. The boat was small, ca. 20 feet over all, four troll lines on two outriggers. Weather was clear and windy. Moderate to rough seas rise – rough seas crest about 13 to 14 feet above the trough. We could not see the horizon when the boat was in the trough, and from the crest frequently all we could see of the rest of the fleet were outriggers above wave tops. All of a sudden a wave popped up directly ahead. We were never sure just how high it was, but it broke over the bow, blew in all the forward windshields, flooded the cabin and almost capsized the boat. It just popped up and came down like a giant fly swatter.
I think I have said this before, but there was a BBC Horizon prog some years back about the 30m waves. Experts fromthe UK Met Office stated that these were 1000 year events. Studies by German? scientists studying satellite photos ofthe oceans suggested there loads of them formed under certain tidal/current/wind conditions!
I would have thought that satellites would be able to spot them all automatically, since they have the know the depth of the swell to calculate the mean sea level. They claim to do that to with in 0.1mm. 😉
Finally we know how Moses did his Red Sea gig. He just solved right equations and lines everyone up at the right moment. Well he probably did not do the maths himself, he got a tip-off from an extra terrestrial deity who was doing some early work of wave interference in the region.
The Egyptians were not on top of the maths and did not realise the trough would not last long. Suckers.
Come to think of it that tank looks about the right proportions to do a Red Sea sim.
One of the few times someone’s post had me LMAO. Thanks, you made my day.
Add a bit of 2D surface focussing by reflection off a concaved coastline like Florida and the Bahamas and you’ll get the same thing in spades at the focal point…. around Bermuda as it happens.
Greg, the coastline has a bit of its own wave-absorptive material at the edge… Sand beach. A concrete wall or stone cliff… Much better wave energy conservation during reflection.
The potato patch just outside the Golden Gate Bridge and SF Bay. The waves there usually go straight up in the air. They are standing waves, and don’t really GO in any direction but up and down. There isn’t any speed at which it is comfortable coming into the gate through the patch when the tide is running.
But I also once got a very nice long surf in through the GG bridge when the conditions were just right for that. That could have been a rogue wave, but it was travelling, and I was surfing down it in a 20 footer center console. Luckily it never got too steep; that was a great ride.
G
Victoria Harbour in Hong Kong is a very good example, lined on both sides with vertical concrete. You know when your ferry has entered the harbour because the ride becomes distinctly choppy – it’s much smoother on the open sea of the Lamma Channel.
“Constructive interference”? How is this not “beating”?
In audio (and almost anything else electronic concerned with waves), two or more out-of-phase waves can combine to either massively amplify the signal or cancel the signal. This was part of my first-year Electronics trades course.
An example. Years ago I did AV installs in clubs. Part of the final tests would be to run a signal (usually a 1K sinewave) through the amplifier and walk around the room listening for loud or dead spots. It’s actually quite eerie to be walking through a room with a 1K sine wave that fades out as you walk through a certain spot and reappear as you moved out of that spot. With a bit of walking around, you could isolate the speaker that was out-of-phase with the others and reverse the connections to fix the problem.
I’m glad that they can simulate and now design around rogue waves… but really? The concept of multiple frequencies causing a massive increase in amplitude as the wave peaks coincide is hardly a new concept.
Not beating because the input waves are not regular as clockwork in the oceans since they are storm driven. The effect you refer to is same interference but driven by regular, harmonic functions.
Rogue waves tend to be individual events not repeated beating.
I’m with Neil. See my comment below.
Neil’s example was of one way to isolate problems in your set up. But that’s just one step in the process. Once you turn the whole system on you have frequencies from 20Hz to 20 kHz. Even in a finely tuned system there are obvious standing waves at certain frequencies, and they break up and form again as people and trays of drinks circulate in the room. There will be spots in the club where you can easily talk to the person next to you, and places where you cannot hear yourself think. If there is no sound treatment in the room, try sticking your head into the corner where you may well hear nothing but a muddy reverb sound instead of a base beat. Sound professionals know exactly what these things are and they pull their hair out trying to get rid of them in any given space.
Walk into any recording studio and have a look at the sound room. All that funky stuff on the walls isn’t there because it looks cool. And those odd looking things stacked up in the corners are bass traps. In other words, the walls, ceilings and possibly even the floor are all covered in material for the express purpose of preventing “rogue waves”.
No, those materials are there to attenuate resonances. It is pointless reversing the phase because that will only work around one frequency. At twice that frequency it’s back in phase and like you say you are dealing with about three orders of magnitude in freq. , or ten octaves.
Many concerts are held in basically rectangular halls which are a nightmare for resonance.
Greg said :” It is pointless reversing the phase because that will only work around one frequency.” Try listening to music through two studio nearfield monitors with the phase reversed on one of them. It can almost make your skin crawl. Proper phasing (and timing) of speakers in a PA environment are typically the first thing you do before you attempt to balance the audio levels throughout the room.
I will admit to being mystified.
Yes, I understand that these sorts of things are difficult to study in an open ocean, but we have studied the living daylights out of them in acoustics. Constructive interference is constructive interference no matter the medium. Ask any sound engineer about the challenges of setting up a good clean stereo system in a moderately sized room. You’ll immediately learn about standing waves, room modals, bass trapping and all manner of problems associated with trying to eliminate distortion, some of which can be so dramatic that it is painful to listen to, just from the sound waves bouncing off the walls, ceiling and floor. Then ask them about the challenges of building good sound for a stadium…
In brief, a “rogue wave” is nothing new. Any experienced sound engineer could probably, after a bit of thought, tell you exactly what to look for as root cause in the ocean.
Waves on water are not linear. You can’t model them with acoustics.
I didn’t say you could.
I said the principles of wave propagation are extremely well understood in acoustics, and that knowledge ought to be an easily transferred base. All these guys seem to have so far is a ripple tank.
waves on sea are gravity waves, not compression waves. They are non linear. Why you assume that you can “transfer” work based on linear superposition to a non linear system.
Linearity makes a world of difference. More like a universe of difference. Why do you think climatologists are so intent on “linearising” everything they touch? All they can understand is are straight lines !!!
waves on sea are gravity waves, not compression waves.
Waves are waves are waves. You can demonstrate constructive and destructive interference with gravity waves, compression waves and light waves. A rogue wave appears to be nothing more than a unique confluence of wave propagation from multiple sources.
In what sense are water waves not linear ??
Water waves can be either transverse or longitudinal . The longitudinal waves can occur in any medium, solid, liquid, or gas. They are simply variations in pressure and displacement in the direction of wave propagation. Since gases have extremely low to zero shear strength, then longitudinal pressure waves are all they can transmit.
Water can propagate longitudinal waves as well as transverse waves. The transverse waves can be of two different types, and they can be quite linear, so non linearity is not a characteristic of water waves.
The two principle types of transverse water waves, are gravity waves, and surface tension waves.
Gravity tends to restore the water surface to perfectly flat, and that process is quite linear. Surface Tension also tries to restore the surface to minimum area which will be flat on the ocean.
But surface tension is only acting on the very surface molecules, whereas gravity works on any depth.
Where water waves do differ from air waves, is in velocity of propagation, and specifically in frequency dependence of velocity AKA dispersion. I can’t remember which of the two, gravity or surface tension is dispersive but you can giggle that yourself.
It is the reason that waves break on the beach. As the water depth shallows, the surface tension force becomes more significant than it is in deep water, and the higher frequency waves speed up in velocity so the water tends to run to the front of the wave, which becomes triangular rather than sinusoidal, until in the end, the highest frequencies dive right off the front of the wave and it curls over.
A sinusoidal profile to the wave is fairly good evidence of linearity and non dispersion.
So I’m guessing that the surface Tension waves are the dispersive ones. Simple harmonic motion is perfectly linear as that term applies to waves. An ordinary back yard swing is non linear because the angle of swing is not small, and the restoring force is not linear with angle but varies with the sine of the angle.
So gravity waves are linear but STs are not.(at small amplitudes)
G
Gravity waves are nonlinear. That’s why waves break when approaching a beach. If you can do it with acoustics, I’ll salute you.
I would disagree with this statement from the article. “Rogue waves … have only been accepted as a real phenomenon by scientists over the past few decades.” I was taught by a lowly college professor back in the early 70s that waves could interfere or amplify each other in any medium, and I have always understood this as the cause of rogue waves. Any scientist who didn’t think that is falling prey to the old ID-10-T error.
And as for predicting rogue waves or areas where rogue waves might occur, like a tornado or hurricane watch area, I think that’s a long way off. And ship’s captains will need lots of proof of actual predictive accuracy (not statistical “skill”) in order for them to feel they’re being prudent in avoiding such areas and not just wasting time, money and fuel (as is the case currently in our battle against CAGW).
I would think that sea captains would be as interested in prediction of rougue waves as they are in prediction of hurricanes, even with large error bars, better something than nothing beyond line of sight.
Greg, I think they would like that, too. But not if it’s 99.9999% false positives.
Greg,
Mickey,
I do what works.
If it is a 10% good signal – and rogue waves are not ‘rare’ [no I will not quantify ‘rare’ or ‘not rare’] in the patch studied, I will go for it, and make it available to my Masters.
But certainly ‘not if it’s 99.9999% false positives’!
I have written about this before on here, but a ship I was on ‘fell into a hole in the North Sea’ in 1984 (March or April, I think).
Constructive interference – what I now call ‘Build-a-Wave’ – did us properly.
The ship – “Iolair”, IMO 7816070 – was modelled to ride the ‘100 year wave’ – which is fine, as that, like George’s tsunami, above, is a very long wave.
We have three wave trains; the Bridge was 75 feet [~ 23 metres] above the waterline, and we had a green wave breaking over us.
Damage to the main transverse platform, set up about a foot or so.
As soon as the storms [multiple storms, multiple wave trains, hence Constructive Interference] had eased, we had naval architect crawling all over the ship. At one point there were, I think, about eight or nine guys with Masters’ tickets trying to explain Build-a-Wave to highly educated non-seamen.
But masses of reserve buoyancy mean that we were OK.
Now think about a bulk-carrier, without too much reserve buoyancy – and then, what if her #1 hatch cover collapsed, letting the sea enter her hold . . . .
‘Derbyshire’, IMO 7343085, lost on 9 September 1980 during Typhoon Orchid. Still the biggest British ship lost at sea.
I didn’t know any of those lost, but I would always, without exception, advise my Masters to steam well clear of typhoons and hurricanes.
Auto
To paraphrase some previous comments and concepts (and with apologies to turtles), one could say:
Climate – it’s oscillations all around and all the way down.
From NOAA:
Rogue, freak, or killer waves have been part of marine folklore for centuries, but have only been accepted as a real phenomenon by scientists over the past few decades.
================
The simple fact that scientists did not accept that rogue waves were real is amazing and it says a lot about scientists because it is quite simple to demonstrate that when two waves interact, the resulting wave height can significantly exceed either of the two original waves.
As such, this article is relevant to climate science, because it shows that scientists are quite capable of overlooking the exceedingly obvious. For example, perhaps climate scientists have overlooked that climate changes naturally, and our current climate change may simply be the result of natural forces.
As such, pouring trillions of dollars into trying to prevent climate change may be a complete waste of money.
Well, to be fair, a rogue wave did come from the sources as the people who claimed they saw giant Kraken in the deep.
Wait, that was real too.
It doesn’t make their claim any less valid. I recall the Captain of Queen Elizabeith II state quite categorically that he was standing on the bridge when he saw the crest of a wave coming towards his ship. His position on the bridge was 90 feet above sea level. This man is a master mariner. Do you want to call him a liar?
they didn’t accept it because they couldn’t model it … they aren’t scientists they are statistical modelists …
It wasn’t until a rouge wave was “captured” on video that scientists stopped dismissing them as old wives tales. I remember a special on one of the edu channels a few decades ago, that covered the subject pretty well.
The constructive interference can also occur in places where an island has created a “shadow” in the wave pattern, after the tail of the shadow you can get rogue waves.
Now that I think about it, I used to create “rogue waves” with my power boat.
We used to take the kids out water skiing, wake boarding, and tubing. On a calm day, I’d pull the kids riding tubes around in a giant figure eight. If you stood up in the boat and paid attention, you could see the “rogue wave” forming. Getting the timing right was a matter of experience, and I missed as often as I nailed it. But if you got it right, you could swing the kids on the tubes right into the face of the rogue wave. They’s slide down the trough in the front, and then right up the face and pop them into the air. If you missed by two or three seconds, that wave was gone, although the outward ripples from the figure eight would continue to propagate across the lake.
Did the same thing :-). The shape that worked best for me was the ‘Christmas tree’ : 14 knots up the right side 100 yards, into the wind, sharp left turn, then down the left side 100 yards, then faster right up the middle. The additiive wave moves straight down the stem of the tree… Very easily seen and timed. The headwind helps, too.
Something like a rogue wave may have sunk the Edmund Fitzgerald. It was a Great Lakes ore carrier that sank on November 10, 1975. There are several other theories.
The received wisdom is that lakers are long and narrow to fit through the canal locks. They aren’t strong enough to go on the ocean. The failure mode would be the bow on the peak of one wave and the stern on the peak of another. That would leave the middle unsupported and the ship would break in half. They’re ok on the lakes because the waves are shorter than ocean waves.
The incident was well investigated. The Canadian Hydrographic Service sent up a vessel the next summer. The insurance companies hired a vessel and a crew of divers. The question was about whether the charts were wrong and the Canadian government could be found liable.
The existing charts were about 100 years old and were found to be remarkably accurate. No evidence was found that the ship had grounded on any known or unknown rocks. If I recall correctly, no unknown rocks were found.
Later, unmanned submersibles inspected the wreck and found no evidence that the ship had hit a rock. I like the structural failure theory because the ship went down very fast. The story was that the ship was visible on radar on one sweep and not on the next, a matter of seconds. I think it’s almost certain that some kind of wave action was involved.
Now I’m going to have to go listen to the song… Does any man know where the love of God goes, when the waves turn the minutes to hours?
Don’t forget to reread https://wattsupwiththat.com/2010/11/10/35-years-ago-the-witch-of-november-come-stealin/
The phenomenon you describe is well know to marine architects and is called sagging, or “hogging” if the center of the keel is supporting the ship with the ends free.
There’s also torsional effects where the ship is twisted and breaks. Whatever happened, it certainly could have been quick.
http://www.cultofweird.com/wp-content/uploads/2015/11/edmund-fitzgerald-shipwreck.jpg
I have had personal experience with a rogue wave while aboard the USS Topeka. I was topside on the 03 level during a storm (a no no on any ship in bad weather), but I always enjoyed as good rain storm. Suddenly I saw a wave coming broadside to the ship. It stood out and appeared to be a hundred feet or more tall.
There was no way I could reach the hatch to go below, so I grabbed a tall pole in front of me, that two radio antennas were fastened to. It was almost impossible to hang on as nearly solid water was washing over me. The structure of the aux radio room is all that broke the wall of water. The ship took a hard roll to port. Looking down the roll was so far that open water was below my feet, as I hung on to the pole for dear life, and unable to breathe because of the wall of water.
The wave passed and I went below decks, and never again wanted to watch a storm at sea. Later I found out that the ship took a 45.5 degree roll: the shipyard had rated the ship for only a 43 degree roll.
Whew!
On the few occasions when ‘they’ managed to get me onto a ship, my favorite place was topdeck behind the wheelhouse because it was the only place I didn’t feel sick. Once again, I feel lucky to be alive.
You were on top of the conning tower? Yikes!
https://en.m.wikipedia.org/wiki/USS_Topeka_(SSN-754)
I think he meant this Topeka.. https://en.wikipedia.org/wiki/USS_Topeka_(CL-67)
A good friend of mine was a submariner and was on board one as it left Norfolk in front of a hurricane. They had to wait for a certain depth before diving and said the boat was moving back and forth about 70 degrees as they went out with the conning tower slapping the water at times. All aboard were puking. I think he considered all waves rogue.
USS Topeka (CL-67/CLG-8), a Cleveland-class light cruiser
https://en.m.wikipedia.org/wiki/USS_Topeka_(CL-67)
A submarine, on the surface, in relatively light weather can be a nightmare. I remember stumbling around, with a trash back tied to my belt, praying we would dive soon. I also remember thanking God we weren’t on the surface when the boat was rocking, at depths greater than 400 feet, when passing under a hurricane.
I had a similar experience on HMS Warspite (the nuke boat) in the 70’s. The only way I stayed in the fin (no submariner calls it a conning tower) was because I wore 2 harnesses. In all fairness though, boats are not designed for the surface, only sub-surface, so the blasted things will roll on wet grass !
I wonder what amount of roll the big top heavy looking cruise ships are rated for?
Steve,
I can only assume that – having no direct knowledge myself – the Classification Society, Insurers, P&I, etc. demand something reasonable.
Cruise passengers are not – generally – young.
My good lady and your present author – combined age about 119 – have been in the youngest decile on at least the last three cruises we have been on, probably all of them!
But a lot of beam, and a bit of draft, should mean that the big cruise ships are quite stiff, so should come back upright quickly – if a bit abruptly!
That said, in the event of a SERIOUS problem, getting north of 8000 people off a ship will be a serious problem. Even in civilised waters . . . . . . .
I am full of admiration for the crew of the Costa Concordia for the job they did: a major casualty, over 3000 people on board, and only a very small, albeit tragic, number of deaths.
A wonderful job by the vast majority of those on board.
Auto – never worse than a small fire at sea for me.
But well aware of how things can go – quickly, badly, tragically – wrong.
These waves are undoubtedly caused by CO2, but only man made CO2. Natural CO2 is ok. /sarc
Why do you think that the Met. Office declared them “once in 1000y events.” ? That way whenever we record one we can go into the “it’s worse than we thought” , “they never used to happen this often”, “it’s the new normal “, etc. etc. mode.
… therefore … if things continue on the current “trend” by the end of the century we will drowning in rogue waves and extreme weather …. gasp …. an’ all that other shit we warned you about but you would not listen because you are paid by Big Oil to support their “anti-science” agenda.
We must act NOW before the world realises we are talking out of our sub-polar vortices.
All of this has been understood for decades and has long been recorded in the anals of science [sic].
That’s a great video, if anyone noticed. Immensely cool.
Yes, my first impression seeing the ‘rouge’ arrive, was that this looked like a soliton wave. These, non dispersive waves occur in canals and rivers with roughly parallel banks. I wonder is this tank is really representative of open water.
I’ll have to show my sons. They don’t care about rogue waves, but watching the Lego pirate ship get flipped will tickle them pink!
We now know that Lego pirate captains honourably go down with the ship.
This is a rogue wave, up close and personal. If memory serves me correctly, this is the MS Bremen cruise ship, which was disabled in the south Atlantic by a massive rogue wave.
https://youtu.be/o0fQ1eWv36o
It amazes me that ships are still not built like submarines… ship builders just don’t seem to get it yet. This wave in the video crested the bow and smashed through the windows… We have transparent aluminum now for ship bridge windows; as well ships should be able to seal up all hatches and other vulnurable surfaces closing them to waves and water. There is no valid reason to not build ships to stay afloat on their side or upside down even. As a son of an engineer I knew this 50 years ago when I was playing with toy ships in the bathtub, why haven’t shipbuilders realized safer ships yet? Budget can’t be the only reason, more likely it’s their stubborn tradition of doing it the wrong way (limited by technology) for centuries that has their ships sinking at sea taking lives with them. Today we’re not limited by the technology or know how, it’s a specific choice to continue the flawed fatal design of building a ship without submarine containment for rough ocean travel, in fact I’d go as far to say its gross negligence to build a ship without submarine containment capability.
“Gross negligence is a conscious and voluntary disregard of the need to use reasonable care, which is likely to cause foreseeable grave injury or harm to persons, property, or both. It is conduct that is extreme when compared with ordinary Negligence, which is a mere failure to exercise reasonable care.”
It amazes me that cars are still not built like tanks.
pwl
Cost Benefit Assessment.
Of course ships can be built as you – and I – would like. More expensive, true.
But – m o s t of the time – ships built more cheaply do NOT sink.
Sorry.
The ship-owner only puts lifeboats and fire pumps on because it is mandatory – it is ABSOLUTELY required by law.
Next question?
Try running ships to a budget set by bean-counters, who will dismiss Filipino staff as too expensive (Even If They Are Competent) and replace them with others – who are cheaper but, bluntly, incompetent, relying on senior staff to mitigate risks.
I have had the phone call in the small hours – “We have had a collision . . . ”
Not good.
Seriously, it is not good – even when nobody had worse than hypothermia.
And – yeah – this is what globalisation means.
Hence multiple compliance costs.
WPCI; SIRE; CDI; Class; PSC; Green Award; ISOs various; FSI; and so on . . . . . . .
Auto – been there – unhappily.
Seen that.
Happily few injuries most of the time.
And we aren’t even talking about mooring – which kills sailors.
Another thread, one day.
PS – Any checklist with more than five – at most – items, will – that is WILL – be ticked blind-folded.
Accept this.
Review and improve your checklists, please.
Rant over.
But I know.
Aalto University (former Helsinki University of Technology and friends) is a perfect place to study waves. First, it is far away from oceanic waves. Second, it got its name from architect Alvar Aalto, whose last name translates as ‘wave’. Alvar means ‘steady’, luckily not ‘study’.
Thanks for that Anthony, a refreshing article about real scientists doing real experiments with real apparatus and publishing real results.
I was worried that this might turn out ot be another computer games study, but then no one has so far claimed that rogue waves are getting worse than we thought as a result of gullible warming.
I love their test, um, boat, er, ship. Quite realistic, I mean so many of us used them in our bathtubs… the music though, quite dramatic. [;-)] Who said science can’t be fun?
Another kind of water wave interaction, for your enjoyment.
from=outro-embed
There are rogue waves and with them the are associated rogue holes (deep troughs). With the rogue waves you get popped (accelerated upward), with the holes you are accelerated downward by gravity then upward by flotation. If the flotation cannot generate enough upward acceleration then you are instantly swamped when the hole ( deep trough) closes. This could be the case with a ship that has a high inertia load.
That poor minifig. Meeting his fate with such stoicism. I salute his bravery.
We were hit by a series of three freak waves about 20 miles off Port Elizabeth near Durban heading into the Indian Ocean. The first wave put us over about 30 degrees and the second dipped the bridge wing in the water……I was standing in the bridge doorway at the time…. We had the helm over and the ship started to turn into them for the third and we got away with it. They looked near vertical. We were in a big Southern Ocean swell from the South West but these three came from the south east. They peaked when they went by and then we dropped back into the original swell. The original was about 60 feet and I reckon these three doubled it easily. We were a 93,000 ton tanker fully ballasted and doing about 15 knots. It stopped us dead even though the engine was still full ahead. Happily it was the afternoon, about force three and sunny so we saw them coming. If I recall correctly I was a Senior Apprentice on watch whilst the 2nd mate was chart correcting. Bencruachen was hit by similar waves a few months before but it was stormy then.
Glad to know that the great world of science is catching up with something that seafarers have known for a thousand years…….Maybe that is why the MET office calls them 1000 year events. Our ship was called “Ottawa”
Perhaps of interest:
Herman, R., “Solitary Waves”, American Scientist, Vol. 80, July-August,1992.
I am not sure why there is such a mystery.
If you create a short pulse you will create a whole spectrum of frequencies. In theory, if the pulse is “infinitely short” then the spectrum will include every frequency. This technique is used to measure room acoustics and also perform modal analysis in engineering.
The mathematics also works the other way round. If you can arrange to have an infinite number of very small frequency components, when they all come together they will recreate the pulse.
Isn’t that what is happening here?
“When waves formed by a storm develop in a water current against the normal wave direction”: what is it that is “against the normal wave direction”? Waves formed? Water current?