The Rogue wave and the sailor

[ZITIBOAT]

Not opposing forces of wind and water. More a synergy developed from harmonic frequencies.
Not always dangerous or super tall but always mighty.

detailed report see my post - https://www.sailblogs.com/member/zitiboat/

[sailormed]

Originally Posted by Seighlor

In the early 1980s, returning to Florida from Newport, Rhode Island on a 44' sailing vessel, we experienced what I could only refer to as a rogue wave. But not what one typically considers a rogue wave to be.

By my recollection, we had some moonlight. Winds were light and we were southbound on an easy reach a bit south of St. Augustine. The sea state was benign. We suddenly became aware of a rolling wave, perhaps six feet high, close on our port beam. The wave was not breaking. It passed beneath us, harmlessly except for a heavy rocking. And we returned to sailing an almost flat sea.

This occurred about midnight with no boat traffic in the area. It was much too large to have been a wake from another vessel. And, if it had been a wake, there would have been more than the single wave.

What might it be called other than a "rogue wave"?

Our neighbours had a similar experience here in the med some years ago. Single wave. They came to the conclusion that the only explanation was that a submarine caused this wave. Not all vessels are moving on the surface of the sea .

[duckpond49]

I've experienced one, though not while in my 35' sailboat.
I was on a passenger ship on an 11-day crossing of the Pacific from Seattle to Tokyo. I was 5 years old. It took me about three days to get over seasickness from the rolling 600' vessel in the gray weather. On about the 9th day, around 4am, the ship rolled quickly to about 45 degrees, putting me hard onto the berth railing in the dark cabin and then settled right back into it's usual roll. It was much discussed at breakfast. So I'm an early convert to the possibility.

[jmorrison146]

Sorry if it's been mentioned before, but "constructive interference" explains some rogue waves. What happens if two waves twice the size of the typical wave train interfere with each other? It will either be "constructive" or " destructive". The vastness of the oceans and the random nature of these wave interactions seem to explain rogue waves. Currents and seamounts have additional amplifying effects.

https://www.physicsclassroom.com/cla...rence-of-Waves

[jimisbell]

My wife and I were walking on the beach in Mazatlan many years ago. We were on DRY sand, 200 feet or so beyond the extent of the wet sand. My wife cannot swim and was carrying two bottles of Champagne. Suddenly people above us screamed a warning, but too late. A wave better than 8 feet high broke over us and dragged us toward the sea. Because the beach was steep and the water drained away quickly, we were able to regain our feet and walk away. Wife lost her glasses but had the presence of mind to hold onto the two bottles. There was never any explanation for that wave.

[Robert Jansen]

The physicist in me informs me that rogue waves cannot arise without some form of contructive interference. This imples that they are more likely to arise wherever there is a convergence of two or more patterns of wind and wave motion.


I don't know whether or not this is useful information, but it might become handy when considering determining whether to stay on one's heading or change course.

[roland stockham]

Originally Posted by Robert Jansen

The physicist in me informs me that rogue waves cannot arise without some form of contructive interference. This imples that they are more likely to arise wherever there is a convergence of two or more patterns of wind and wave motion.


I don't know whether or not this is useful information, but it might become handy when considering determining whether to stay on one's heading or change course.

Perfectly true, in fact all the variations we see in waves are the result if different wave trains interacting. A 'pure wave train would have all the wave traveling at the same speed and direction and all the same size but this never happens at sea. When 2 or more wave trains interact some of them add (in phase) and some cancel (out of phase). This potentially creates periodic 'flat spots' and waves which could be the sum of the heights of each individual wave train added together. There is however a limit. Since the interference only combines the wave height not the wave length it created progressively steeper (and therefore more dangerous) waves up to the point where the wave is so steep it cannot support itself. The result is sometime called a 'haystack' and looks like a column of water tumbling and breaking on multiple sides. It can occasionally for a linear wave but I suggest that is rarer and only occurs where there are multiple waves traveling in the same direction. I think that may be the ones reported in the southern oceans.

I believe NASA did some research based on satellite imagery into this phenomena a few years back but I no longer have the reference.

[edl]

Back in February 76 when I was in the Navy, we were coming back from the med. Enter a Full Storm, 40 foot waves, that old LPH was rolling to 21 degrees with a point of no return being 25 degrees. The flagship suddenly radio that they took a wave through the Bridge and also lost there surface search radar antenna (situated 80 feet above the water line) Over a dozen seriously injured. One Sailor was injured so bad he needed surgery but it was two rough. On the Inchon we launch our Helicopter which hover over the flagship flight deck and winch the injury sailor aboard and then flew on to Cherry Point. When we pulled into Moorhead city the surface search radar antenna an mounting were completely gone off the flagship. They determine it was a rogue wave at least 90 feet. Our Ship's Bosun a old veteran of 35 years said it was the 4th rogue wave he heard of. Note both pilots receive the DFC.

[Don C L]

Originally Posted by edl

Back in February 76 when I was in the Navy, we were coming back from the med. Enter a Full Storm, 40 foot waves, that old LPH was rolling to 21 degrees with a point of no return being 25 degrees. The flagship suddenly radio that they took a wave through the Bridge and also lost there surface search radar antenna (situated 80 feet above the water line) Over a dozen seriously injured. One Sailor was injured so bad he needed surgery but it was two rough. On the Inchon we launch our Helicopter which hover over the flagship flight deck and winch the injury sailor aboard and then flew on to Cherry Point. When we pulled into Moorhead city the surface search radar antenna an mounting were completely gone off the flagship. They determine it was a rogue wave at least 90 feet. Our Ship's Bosun a old veteran of 35 years said it was the 4th rogue wave he heard of. Note both pilots receive the DFC.

Welcome aboard edl! Thank you for that!

[Icarus]

Originally Posted by LongRange

The Perth Maritime Museum has a 90' high marker behind the statically displayed Parry Endeavour, to give some sense of the scale of the waves that Jon Sanders faced on his triple circumnavigation. It's like looking up at a small mountain.

Then again, I'm kinda scared of dying of a heart attack in the office, triggered by yet another corporate inanity, and in my case that is far, far more statistically probable than encountering 90' waves.

I'll second that.

[JDGreenlee]

The Agulhas Current is infamous for rogue waves when a Southwest buster comes around Cape of Good Hope. A thankful shout out to the radio volunteers along the Wild Coast of Africa who help yachties round the Cape of Storms by providing WX and the benefit of experience. I'm especially indebted to the sailors of the Buffalo River Yacht Club in East London for scrounging a new steering cable after a rough passage from Durban mostly on the emergency tiller, and those in Mosselbai for advice and encouragement. The Royal Cape Yacht Club is well worth the risk. What a storied bar!

[olewsaa]

I would like to put bring some scientific and fact about these waves. Prior to the Draupner event i Norway in 1995 where a wave higher than what the models at that time could predict most stories about such waves were classified as drunk soldiers stories. They could not simply exist, at least not the the eyes of scientist who continued to believe in linear models of the waves. Such waves were unscientific.

The Draupner wave was a piece of solid evidence that changed many scientists mind and work was initiated to look into this. One BBC documentary explains the story bind this. In oder to explain these waves a more sophisticated none linear model was used to model the ocean waves, in addition to the fact that if you start looking for them they are actually not that uncommon (I must admit that my degree is in Chemistry, not wave mechanics).

Conferences were arranged to settle this and today the knowledge of these waves are on a very different level that just prior to the year 2000.
On the more scary side is the inverted wave, just like to bottomless cone opening up before you. They are rare, but do exist, both in real life and om computer models.

Quite recent studies have revielded more knowledge about these waves, a tank experiment show one way of creating such a wave. Superimposing it to the famous "Great Wave" also give credit to historic observation of these waves.

Today these waves are absolutely scientific and are well studied and understod well (soon well enough to predict them ?).



Regards,
Ole

[jimisbell]

That BBC documentary is enough to make you want to stay at home in front of the fireplace.

[bouncycastle]

The Mediterrean sea can be a very nasty sea even without large waves. If you look the shapes of the local Mediterranen boats like 30 to 60 foot fishing boats they have a different shape than a Atlantic type boat has . The waves in the med are short and sharp and even a force 6 can create the types of waves that just land in cockpit and sink sailing boats very quickly . Whatever way the wind blows the top two feet of the sea will move the same direction making sailing or motoring against the winds sometimes 60 MPH plus in a Mistral often a waste of time for boats less than 60 feet as larger boats with larger powerful engines can maintain some headway . There every wave is a bad wave stopping the boats forward progress into short sharp waves. The Mediterranean boats developed their shapes from They say the old style Roman empire boats that we're basically nearly a round plate shape nearly as wide as they were long . This increased the cargo they could carry using wood beams and planks as building materials but gave them terrible direction steering abilities. The logic was a storm they went the direction of the wind because they had no way not to steer any other way .However no matter what side the boat presented itself to the waves the result was the same so less risk to overturn with broadside waves .A Cargo boat of that Roman empire doing a journey from Rome to Palistine in those times could take a entire summer with lack of winds and high probability of being storm wrecked each journey. The fishing boats of the region show this very wide in Center shape often with very narrow sterns sections as they went from full round to more pointy ends . The atlantic with big swells allowed boats to have very pointy ends or allow wide stern sections . In late1980's region 6 sailing boats about 30 foot long from French boat maker will delivery crew often single handers in formation going to Greek sailing flotilla early April sank at the same time between Italy and Corfu from sudden local storm in Adriatic . All the boats took a wave into the cockpit and then every wave after that entered the boats and sank them in minutes making it a jump up to the life raft exit . A USA aircraft carrier in the region saved the six hapless crews and formed a large island lee wind protection for the 4 other 30 foot sailing boats that were not sunk by the same storm . Many old hands of the Med won't bother to sail if the wind will be force six or stronger as often the Mediterranean boat insurance doesn't cover them fully or properly in winds above force 6.

Lake Errie in the USA is also notorious for large ships sinking in storms due to short sharp wave patterns .

Something big must have been knocked a 65 foot Volvo round the world racing boat upside down. a few Hundred miles short of Cape town South Africa . Having talked to the sailor who was resting below when this went down seems there isn't a limit to size of big waves out there looking to show us there is real big waves out there hunting down our sail craft and the big ships when they can get them

I suspect there are no perfect shaped mono hulls that can cope with monster waves of roaring forties down to micro demon waves of Mediterranean or similar closed sea with short sharp waves patterns

[BrotherT]

Sailed off the South African east coast for years. Local knowledge is that a strong cold front or low pressure system against the Agulhas current ON THE EDGE OF THE CONTINENTAL SHELF where it goes into deep water is one of the conditions for abnormal or rogue waves to form. Large commercial ships have been lost with all hands off the SA east coast in these conditions, and the prevailing safety advice is to either head well inshore or well offshore, but definitely away from the edge of the continental shelf. If you look at the continental shelf "bridge" between Australia and Tasmania and East Australia current setting against low pressure fronts, this is likely one of the reasons for the abnormal waves to hit the 1998 Sydney to Hobart race with its loss of 6 men and a number of yachts in those conditions at the edge of the continental shelf. So beware those conditions in those areas - but these are not the only conditions known to generate freak waves as Adlard Coles has observed.