The Rogue wave and the sailor

[roland stockham]

I think we all experience 'rougue' waves more often than we appreiate. Whenlooking at wave hights the 'expected' spread is about 2.5 times either side of the mean. So if mean sea is 1m anything more than 2.5m or less than 0.5m is 'rougue'. However the reality is that waves follow a standard distribution curve so the will always be waves outside the norm. It' just that they become incresingly less common. The problem for boats is that these waves don' have a corrisponding increase in length so they are not ony higher they are also steeper and that makes them dangerous. Add it to the list with lightening strikes, inattentive bridge officers etc and live with it. The world is a hazarous place an can and does kill people evrery day.

[rmlarson1098]

Originally Posted by Dan Mosby

While cruising through some sailing vids on the %$#@Tube, I ran across a video concerning the "Draupner Wave" of 1995, which was the first "rogue" wave ever documented thouroughly with any kind of measuring equipment.

The pic demonstrates that a rogue wave is 2 to 3 times greater than the "average" set of waves...which becomes problematic in an evironment with, say, 10 meter seas. That's 90 meters of Neptune's fury coming down on you with about 100 tons per m2 of force. Not good.

Apparently these giants are more likely to form when areas of strong ocean current encounters strong opposing winds. High latitudes are especially susceptible due to the rotating masses of air at the poles, which makes places like the north sea and both the southern capes especially dangerous. Combine the storm season with the gulf stream, or any similar stream in the pacific, and you have all the ingredients you need to experience a rogue wave at lower lats.

Since these things are capable of taking out super-tankers, cruise ships, and oil platforms, the traveler in the 40 foot yacht would be wise to plan their journeys extremely carefully around those parts of the ocean susceptible to strong currents and storm winds, as a 90 foot wave might just be a bit much for the ol' westsail 32.

Anybody ever encounter this phenomena personally? If so, where?

Be careful out there, and mindful of the current.

Well, my wife and my aunt did, while sailing from St. Thomas to Martinique.
I'm told it was a beautiful, sunny day, perfect breeze with 6-8 foot seas.
My aunt glanced to the north (to port as I recall) and noticed what at first seemed to be a low, treeless atoll. It turned out to be a 'wall' of water, which she (a long-time bluewater sailor) estimated to be 30 feet high. As it turned out there were two, one following the other, and the ladies had just enough time to arrange the boat stern-to the 'rogue' swells. The waves weren't breaking but were apparently quite steep and the boat, a 41' Dickerson ketch, surfed a bit down the face(s) as my wife yelped at the helm.
No one at Martinique, or later back at Red Hook knew anything about any 'rogue waves', so apparently a local event? Spooked my wife though who was never all that comfortable offshore, and in fact that was her last ocean passage.
Along with the obvious connection to latitude, there's a lot of luck involved here too, for better or worse. I worry a lot more about lightening strikes than rogue waves.

[ArmyDaveNY]

Originally Posted by Dan Mosby

2. Rogue wave decides to help with some enroute bow modifactions

Apparently 15 tons per m2 is the design goal for structural strength for most big cargo vessels, but new calculations have determined that the 100 ton per m2 is what it would take to defend from a breaking rogue. That's insane.

I find the name of this ship rather ironic. Perhaps it is time to change the name to Energy Absorption?

[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"?

[StoneCrab]

I watched a documentary about rogue waves that investigated the phenomenon from space and with a look at sensors on oil rigs. The space based analysis was the most interesting. It showed that it happens all the time and pretty much everywhere. The amount of energy and size varies by region but they are more frequent than anyone previously imagined. The statistics are in your favor due to the size of the ocean that you will not encounter one, but they are out there.

[Dan Mosby]

Originally Posted by mabowers

In 89 on USS Carl Vinson ....

Had a cousin who served on that ship back in the day. Did some things on the USS Saipan and New Orleans myself, both of which were de-commissioned. Those decks were high, though I doubt nearly as high as the C.V. because they were rotary wing carriers for Marines.

[tarian]

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"?

Intresting and Scary
Some of these rolly waves people are encountering can be because of the under water topography , i.e sea mounts , and deep earth quakes causing small tusanmis miles away from you current location.
Also landslides under water will cause a movement in the water above, what we dont see below can cause so much above.

[Dan Mosby]

Originally Posted by Seighlor

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

That's the one.

They can be 6 feet in a 2 foot sea, or 90 feet in a 30 foot sea.

I bet there's a connection between them and underwater tremors along the faults as well, and not just wind and current issues.

Regardless, I bet there's more rogue shipping containers out there lurking, waiting to strike, then any amount of gargantuan, Mosby sinking rogue waves.

[newhaul]

Originally Posted by Dan Mosby

Had a cousin who served on that ship back in the day. Did some things on the USS Saipan and New Orleans myself, both of which were de-commissioned. Those decks were high, though I doubt nearly as high as the C.V. because they were rotary wing carriers for Marines.

on the chuck wagon
the waterline was mid deck 4 so approx 60 ft from flight deck to the lwl at full combat load .
And the rogue that swept the deck was at a minimum of 75' .

When was your cousin on that prison .

( ht3 to HTC '86-'92 on her)

[dsleyland]

Yes
May 2012 in the North Atlantic about two days sail west of Horta in the Azores. The incident was covered in Sail magazine, September 2012. The storm system erupted off Labrador and grew to be 1000 miles in diameter. Winds were about 45 knots. Sea state was 15 to 20 feet confused seas; occasional waves of 25 or more but they were benign. The waves appeared to come from three directions once, which of course was due to the fact it was moving rapidly. At one point we decided to go hove to and let the storm pass. We were fairly comfortable for about 8 hours. Then about 0800 hrs we felt the sensation of being broadsided by a locomotive. The crushing wave drove the port side of the boat into the sea with such force the rub rail detached and hull around the chain plates flexed enough to crack the gel coat. The dodger was crushed down against the winches. I have wondered how large that wave was.

[Paul Howard]

How many times have you won millions of dollars in the lottery?
And the odds that you will encounter a large rogue wave at sea is even less likely.
There will always be excuses and fantastical fears to help someone avoid doing something they have never done before. I have sailed 130,000 nautical miles from 66degrees 40' North lat. to 57degrees South lat. around Cape Horn, circumnavigation of the world, etc. The only rogue wave I have encountered was off the Portuguese coast, average waves about 5 to 6feet, rogue wave coming across the wave train of about 12 feet was a surprise, but did no harm.
Some people like to tell scary stories - seafearing tales - others go seafaring.

[Mike Banks]

My late father encountered one somewhere near Madagascar.

They were in radio contact with about seven other ships in the general area, or had been recently. My father was on the bridge at the time, he was captain, and it was a tanker carrying oil, if my memory serves me well.

Anyway, they noticed what looked like a large bank of low cloud was quickly smothering the stars--and they realised it was an enormous wave.

By good fortune it was coming almost directly at them, and by putting on full power and steering into it for all they were worth, they were able to move the stern around enough that they went through the top of the wave rather than being rolled over by it.

They lost most of the deck gear, I think some lifeboats went over the side, as well as fire equipment, life belts etc. All they saw after the wave passed were some flames on the sea from the life belts torn from the rail. Their topmost radio antenna survived--it was rigged between the two masts which also withstood the 16 knots plus of water rushing past as the speed of the wave and that of the vessel combined. Had it not been a tanker with its lattice of frames for the tanks giving it tremendous strength and rigidity, it might have suffered a structural failure, popped a lot of plates and sank. In those days back in the 1930's a lot of ships were still riveted together.

Afterwards they could only contact about three of the ships--they had either lost their radios or foundered.


Father went through the entire second world war serving as an officer on tankers or captaining them--Murmansk, the Atlantic and Malta. Only two of the class of fourteen that went to the navy convoy school signals course survived the war--he was the only one uninjured of the two.

Then he survived the wave. He must have had more arse than an elephant--

[wingssail]

On the east coast of Africa, where Agulhas Current meets southerly storms, many ships have been lost due to huge waves. (This caused a lot of anxiety on the Wings crew as we anticipated an approach to Africa.)

However, there is pretty good weather forecasting now and it is possible to avoid travelling on that coast if the conditions are going to get bad. However, when the weather radio broadcasts a warning about "abnormal waves", you need to get to shallow water asap (inside 100mt depth there is much less current and the waves don't get so big).

In this photo we just got "that" warning, and we're running for it. Never saw a big wave though, lucky us.

[Dan Mosby]

Originally Posted by newhaul

When was your cousin on that prison .

Early 80's time frame. Can't say what MOS he was though. Having been on the "baby" carriers and seeing how tough those bastards are, it's hard to fathom how something as large as a fullsized can get fooked up by Neptune's wrath, but I don't think the ships been built that can't be tossed around like a stick by the oceans when they get pissy, and I doubt we ever will.

[Dan Mosby]

Originally Posted by Paul Howard

There will always be excuses and fantastical fears to help someone avoid doing something they have never done before.

This thread is not about fear, it's about science, awareness, personal experiences, and making good decisions.