# Rogue Waves...something to keep you up at night on long passages



## thesnort (Jun 2, 2007)

The New York Times > Log In

Just by chance, I turned on the radio this morning and caught Paul Harvey Jr. talking about these. 
I won't ask if anyone here has seen one because I doubt you'd be around to tell about it. Something to think about though, eh? 
OK, I apologize now. Melatonin works wonders for helping you get some sleep.


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## Valiente (Jun 16, 2006)

I had heard recently that satellite monitoring had grown so discerning and widespread as to see rogue waves from space, and perhaps to give some warning of them to shipping.

Ah, here we go:

Rogue Wave Detection

Slashgeo | Using Radar Data to Detect Rogue Waves

Rogue wave detection & mitigation | Seasteading Institute


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## jaschrumpf (Jun 22, 2002)

thesnort said:


> The New York Times > Log In
> 
> Just by chance, I turned on the radio this morning and caught Paul Harvey Jr. talking about these.
> I won't ask if anyone here has seen one because I doubt you'd be around to tell about it. Something to think about though, eh?
> OK, I apologize now. Melatonin works wonders for helping you get some sleep.


I experienced a rogue wave in the Patapsco River just outside the Key Bridge in Baltimore!

My nephew and I were sailing out of Rock Creek and were just NE of the White Rocks, about a half-mile. The winds were about 10-15 kts out of the NNW and the average wave height was about 1 1/2 ft.

Suddenly the monster appeared! We were close-hauled on the starboard tack when I glanced out over the side and _*there it was*_!!! Rapidly gaining on us was at least a four-foot swell, all by itself and coming from between us and the south shore of the river. Nothing was over there to send up a wake, nothing had been there. All we saw was this kinda scary, much-higher-than-anything-else-around swell coming on our port beam.

I figured I'd rather take this on the quarter than on the beam, so we tacked over and watched it come up on us. When it reached us it was at least at foot higher than our transom, but the stern rose to it and it passed under us and moved on, and we watched it die out about a quarter-mile away.

Weirdest thing I've ever seen on the river. Spooked me for a good half-hour.


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## JohnRPollard (Mar 26, 2007)

This part got me thinking....



> The MaxWave team, led by Dr. Rosenthal, examined three weeks of radar data and to its amazement discovered 10 giants, each at least 82 feet high. "We were quite successful," he said....
> 
> ----
> 
> Another birth ground is seen as choppy seas where several waves moving independently merge by chance. But scientists say a giant of that sort would live for no more than a few seconds or minutes, whereas some [rogue waves] are suspected of lasting for hours and traveling long distances.


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## Sapperwhite (Oct 21, 2006)

I too have experienced the dreaded *Rogue Wake*. The area around seven foot knoll is big time rogue wake territory.



jaschrumpf said:


> I experienced a rogue wave in the Patapsco River just outside the Key Bridge in Baltimore!
> 
> My nephew and I were sailing out of Rock Creek and were just NE of the White Rocks, about a half-mile. The winds were about 10-15 kts out of the NNW and the average wave height was about 1 1/2 ft.
> 
> ...


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## Omatako (Sep 14, 2003)

A similar phenomenon is occurring in sporting events, especially athletics. Obtuse?? Yes but maybe not as much as you think.

With each passing major world sporting event, new world records are being set almost routinely. Are the records really being broken? Maybe but then again maybe not. The timing devices are getting more and more accurate so the margins are getting smaller and smaller and where we were once recording with analogue stop watches and an average thumb on the button, now we're recording down to 1000/s of a second with laser beams and other whiz-bang devices. So the speed at which I run today may be the same as that which was run some years ago but I'm being timed better.

What has this to do with rogue waves? Well, these waves are not new, they have been around forever. The difference is we now have the ability to find them, record them and as technology improves, we'll find more and more methods to scare ourselves.

One thing is for sure - I won't be losing any sleep worryig about rogue waves.


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## sailingdog (Mar 19, 2006)

Why should Rogue Waves keep you up at night... not jack you can do about them...so why let it ruin your sleep.


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## WouldaShoulda (Oct 7, 2008)

jaschrumpf said:


> I experienced a rogue wave in the Patapsco River just outside the Key Bridge in Baltimore!


One long ago experience stays with me to this day...

Though not a "rouge" by any means, when I was a lad we spent much time on the shores of the Elk River.

Shipping from the C&D went by regularly, but one day a particularly large and speedy vessel went by.

The water level suddenly dropped from my chest to my feet.

Just as suddenly, the wake appeard.

The five foot cascading wall of water was pretty intimidating when you are only three feet tall!!

I still have nightmares of receding water, fish flopping around and such, then a devasting tidal wave.

Yes, I'm naked too.


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## CharlieCobra (May 23, 2006)

There's been more than a few boats taken out by rogue waves. If it's at night, not a thing you can do. In the daytime, if alert, ya might get bow on in time.


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## CalebD (Jan 11, 2008)

In spite of all we know and how much better we may be able to measure and track natural phenomenon there is still a lot we don't know. 
Tides cause waves. We all have seen this in tidal rips and races. I have noticed this phenomenon since I was a teenager sailing on the LI Sound which does not have a rip roaring current flowing through it where I was. Sets of larger then normal waves would come up from out of nowhere and no boat had passed by. There is a science called fluid dynamics that can perhaps explain this, standing waves and whirlpools. Sometimes all it may take is a Spring tide situation.
We were racing on the Hudson River late this summer around a Spring tide and it was getting dark. All the boats in our fleet were getting set up river of the last mark to round the last turning mark. The tide was nearing its turning point to ebb but was still flooding north. Out of nowhere (and there were no tugs with barges in sight anywhere) we got a set of 3+ foot waves that took everyone by surprise with some boats pounding or rocking violently or both. The tides don't always move evenly in an organized fashion. My guess is there was a last bulge of flooding water coming through at that moment that caused these waves - but that is only my guess - it could also have been a cruise ship coming up the Hudson to Manhattan 25 miles below that sent a bow wave up the river.
Rogue waves on the ocean are another animal altogether although who is to say that tides or current do not have something to do with them as well as prevailing winds and barometric pressure.


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## billyruffn (Sep 21, 2004)

*Rogue troughs*

Scene: a company Christmas party in Boston many years before we bought the boat. Wife and I are well into our second glass of wine, chatting up a couple who a year before bought their boat. They've just announced they are quiting work in the spring, selling the house, and moving onto the boat permanently. In my wife's eyes, they're experts. The conversation goes something like this:

My wife: "I'm comfortable with coastal trips but offshore makes me nervous. I've heard that there are 'rogue waves' that can swamp a boat". 

Jack (the guy who's going sailing): "Awh..., you don't need to worry about 'rogue waves'. You can see them coming and you turn the boat to take them bow on. What you really need to worry about are 'rogue troughs'. They can sneak up on you." 

My wife: "Rogue troughs?" 

And turning to me, she continues: "You never told me about that"!   

Jack: "Oh yea! They're really dangerous!! They're the opposite of rogue waves, but they only occur on flat calm days. You're out there motoring along 'cuz there's no wind, of course --- and all of a sudden... the water drops out beneath you and you fall into the tough. It can swallow a boat in seconds. There's no way to escape."  

My wife, looking at me: "I'm not going!"   

Me: "Thanks, Jack!"

At the time it was not funny, but Jack and I still laugh about it today.:laugher

Jack and Laurie are now in their 10th year of crusing and to my knowledge they've never encountered a rogue trough. For that matter, neither have we.


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## hellosailor (Apr 11, 2006)

I think after the sea surface analysis satdata came out, they figured there are over 1000 rogue waves--the 100 foot plus kind--out every year.

A four foot wave in a river I'd call a wake or a heavy tidal bore, not a rogue wave.


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## downeast450 (Jan 16, 2008)

My wife, Jeanie and I had an "interesting experience" while motoring across a shoal near the 60 fathom line in our day sailor a Marshall Sandpiper. It was flat calm and we were headed for a picnic on Baker Island off Mount Desert Island, Maine. In an instant a large wave rose and broke on us. It hit us bow on and if we had been another 10 yards further out we would have been flipped on our backs. It broke and buried us. Green water hit the mast. It filled the boat and washed stuff out over the transom. That amazing little boat just bobbed up and the motor was still running but the prop was cavitating badly in the foam from the wave. I only had time to say "hold on" and we were under water. A second one followed. That one was not as big as the first but it filled the boat again and washed over the transom. The engine continued to run and no more waves showed up. A small outboard boat was fishing near by and watched the whole thing. I didn't know what to do so I waved and began emptying the boat with a bucket. It was a beautiful day and we made it to Baker Island. It could have turned out very differently. I am now careful to look at inshore charts in this area with an eye for east facing walls that shoal up around the 60 fathom line. That bit of energy could have come from Spain!


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## Valiente (Jun 16, 2006)

That could have been the energy from an underwater landslide or "slump" in the Canary Islands. My understanding is that they aren't always noticed.

There was a documentary a couple of years ago on this, because one of the Canaries is bisected by a fault line and the side facing North America could slide into the abyssal plain, creating a "mega-tsunami" that wouldn't manifest until it hit the east coast (or more properly, the continental shelf) of North America.

Technically, though, there is a big difference between breaking waves, tidal overfalls, tsunamis and rogues. Rogues, I have always understood, are purely wind-driven waves that sync up with other waves and come at you either out of the blue on a flat sea, from an odd direction, and/or as a single, much bigger wave in a series of smaller waves.

I do not get the impression that sea-bed conditions, tides, earthquakes or proximity to land play a role.


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## SimonV (Jul 6, 2006)

I don’t know if they were rogue waves or swell, but crossing the Pacific I did on more than one occasion see much larger humps on the horizon and would watch these move closer. What made these stand out was they were not travelling in the same direction as the prevailing swell and there would only be one or at most three staggered across the sea. They did not have a defined face being more of a hump, the nearest I could describe them would be to use the analogy of an upturned plate lying on the table top, you could feel the power and lift when they went under the boat. Hey, I was there on my own but I did see them; I think.


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## sailingdog (Mar 19, 2006)

And you thought you saw mermaids too... 

I think the fact that they were in groups of up to three and in a different direction than the prevailing waves makes a good argument for them being rogue swell.

waves=sea state caused by local winds
swell=sea state caused by distant winds, that have travelled to you.



SimonV said:


> I don't know if they were rogue waves or swell, but crossing the Pacific I did on more than one occasion see much larger humps on the horizon and would watch these move closer. What made these stand out was they were not travelling in the same direction as the prevailing swell and there would only be one or at most three staggered across the sea. They did not have a defined face being more of a hump, the nearest I could describe them would be to use the analogy of an upturned plate lying on the table top, you could feel the power and lift when they went under the boat. Hey, I was there on my own but I did see them; I think.


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## Bene505 (Jul 31, 2008)

Lenses. Thats what I think rogue waves are all about. Bottom formations curve wave front directions. I'm pretty sure currents do too. If you happen to be in the focal area, you're like an ant under a magnifying glass. All the waves pile up where you are.

Waves travel faster in deeper water. If there's a long mound of less-deep water in-line with the wave direction, then the waves along the wave front will converge -- they will decrease in perceived breadth and gain in height. Somewhere down that mound the waves will pile up. The higher the mound is (in percent of surrounding depth), the less long the mound has to be, and the closer to the mound you'll find the piled-up waves.

I would think that very specific bottom contours could be very effective in converging wave fronts and creating higher waves that would remain converged. This is not the old interference pattern of choppy, higher waves in a specific location only. It is a focusing of the wave that would persist as the wave travelled onward.

Good thing is, with time and computer processing of bottom contours and currents, it ought to be possible to show where these spots are for any given wave direction. And I would think modeling the wave direction from the Canary Islands and other locations of probable underwater landslides would be high on the list.


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## tweitz (Apr 5, 2007)

This is a great thread. My sense is that rogue waves are a perfect example of the chaos theory, where there are so many complex variables and effects of subtle changes in initial condition that it becomes essentially impossible to predict the exact condition at a particular future place and time. It is part of the reason why the weather turns out to be so hard to predict over any long period of time. Take a look at the Wikipedia article on the "Butterfly Effect" for a description.


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## Valiente (Jun 16, 2006)

SimonV said:


> Hey, I was there on my own but I did see them; I think.


I think you did as well, and probably that "rogue swells" are the precursors or the "junior version" of rogue waves.


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## Cruisingdreamspress (Apr 8, 2008)

*Rogue Waves*

Fellow Sailnet members, who have added their interesting comments and opinions regarding 'Rogue Waves,' have motivated me to chime in. 
First, there is no doubt that rogue waves do exist although I believe the odds of encountering such a phenomenon are rarer than lighting striking people; pirates boarding yachts; shark attacks, or ships sinking pleasure boats. These things do happen but (so far) never to me.

Nevertheless, somewhere in the world's oceans, rogue waves are building and dissipating at this very moment. How many&#8230; is a guess. Some might suggest 5 to 10 while others might say 50 or more. Whatever the true number, it will never come close to the number of ships and fishing vessels that ply the world's watery highways.

Statistic suggests that just sighting a ship is hundreds, perhaps thousands of times more likely than being struck by a rogue wave. Yet sighting a ship in the vast open ocean is, in itself, a rare event. For example, during my first 35 days at sea as I began my seven -year solo voyages around the world, (while maintaining a watch schedule that was more conscientious than many fully crewed boats. See thread on 'Kitchen Timers) I saw only one ship. I have never encountered a rogue wave as others describe it in 30 years of being on the water.

During all my time at sea, however, I have, of course, encountered larger than normal waves but calling them 'rogue' would be an exaggeration. I once took green water over my boat after being hove-to in a 'southerly buster' off the coast of New South Wales, Australia. A large wave ripped out a stanchion in the Red Sea. A 25 footer loomed up above his 18 foot companions in a 50 knot gale off the Venezuela coast and my boat went over the falls and skidded down the wave on her side. However, this was not a rogue. It was the last big roller in the set. All surfers wait for this wave.

So why is their so much chatter about rogue waves? Why do many authors use the term? I think in some cases, while telling these sea stories, it sounds so much more titillating to claim&#8230;' Yes, it was a rogue wave that did me in,' instead of saying &#8230;' Yep, I messed up. Not paying attention to prudent seamanship.'


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## Valiente (Jun 16, 2006)

Thanks for this post. You are right in saying that perhaps we shouldn't worry over events both rare and for which we can't make provision. 

What is likely to never be known is the percentage of boats that disappear due to storms, collisions or rogues. The occasional huge tanker or freighter shows up with a stay or a scrap of sail wrapped around the bow bulb, but if someone is very quickly sent to the bottom, even an EPIRB might not mark the event.


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## CatfishSoup (Nov 23, 2008)

I recall a story of rogue waves in lake Huron...A tug was working out of Port Austin harbor in 5-7 foot waves, when it was capsized by what stander-bys and crew described as a 15 footer. I believe everyone survived. Even though the wave was only 15 foot high, i think it can still be considered a rogue because of its relative size to the normal conditions. We also have what we call the three sisters in the great lakes, a set of three exceptionally large waves that i have witnessed several times. I do not classify them as rogue waves by any means.


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## camaraderie (May 22, 2002)

I've read that one in every 1000 waves is double the average height.
So if you are in 15 foot seas with a 10 second interval you will get a 30 footer once every 2.5 hours or so. I think the defining characteristics of a true rogue is that it is way more than double the height of prevailing seas and often comes from a different direction.


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## AdamLein (Nov 6, 2007)

Cam: interesting. Do you know what the wave-height distribution is supposed to be?


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## camaraderie (May 22, 2002)

Not off the top of my head Adam...will have to do some research but it is an interesting subject. The "significant wave height" is defined as the average height of the highest 1/3 of waves so "15 foot seas" would be the average height of the highest 33 out of every 100 waves. One would assume the other 2/3 of waves would be CLOSE to that average...with maybe 1/3 less height at the most just based on observation. You don't get average 15 footers then a 5 footer.


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## Valiente (Jun 16, 2006)

Of course, even to be perceived as a rogue wave, it would have to hit you and at the right angle and time, and speed. If you were on a broad reach, but going well, and the "rogue" wasn't breaking, you might just be lifted and carried along pleasantly. I suppose you might be at the top, looking around and saying "Hey, I see land...odd...I should see land for six hours yet..." but otherwise it could be benign.

I've seen and been in large Lake Ontario waves, and the effect of a "surprise" one was to essentially bury the bow and get about a foot of green water running straight back to the cockpit. The thing I remember, however, was the sound of the prop (I had the engine running at low speed because I thought I might have to come in in a hurry) coming free of the water. Never hear that before and would prefer not to hear it again.


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