Flippin' eck!!

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nicho

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Flippin\' eck!!

You may remember, I had the misfortune to suffer at the hands of some 8 metre Atlantic waves recently. I thought, in my inexperience, they were huge (though they were steep sided), until I read the RNLI Mayday supplement in the YM just delivered! When John Passmore had to be rescued off NE Scotland from his capsized catamaran, the helicopter had to find a gap between 30 metre waves (that's 100'!). It set me thinking, what are the highest waves that have been recorded? Anybody know??

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Re: Flippin\' eck!!

From memory the Guinness book of records puts it at 112'.

However somewhere (Greenland or Alaska ? again from memory) part of a mountain collapsed into a fiord creating an enormous artificial wave of something like 2000-3000'.

From the recent BBC programme on Rogue waves a 30m wave is possible but it is a highly rare and isolated event. Therefore when they say they had to rescue John Passmore from 30m wave(S) I think that they probably meant 30 foot waves.

John

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Re: Flippin\' eck!!

there ae some stories in the books, 'The perfect storm' and 'Fatal storm' of rescue helicopters hovering at 100ft and nearly getting wiped out by waves

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Re: Flippin\' eck!!

No, the conditions that night caused report sea's of 30m, it is a while since I read the story but from what I remember wasn't there a funnel of two lows whipping the wind and sea up to something crazy?

Being the first heavenly twins to go over, it was somehow comforting that she survived so long in what sounded like a one off situation weatherwise. Also the fact the vessel was later lifted from the sea as it was found bobbing about around one of the rigs.

Out of interest, does anyone on here know John Passmore, I have tried getting in touch, but so far have not been able to find a current contact address.

<hr width=100% size=1>Julian

<A target="_blank" HREF=http://www.topcatsail.co.uk/movies.html>Dolphin Movie From Top Cat</A>
 
Re: Flippin\' eck!!

You're referring to the rescue opf the crew of Kingurra.

The helo was holding a 100' hover, when the pilot saw a wave ABOVE the helo. The pilot climbed 50' - and the radio altimeter measured the wave as passing 10' below the fuselage.

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Re: Flippin\' eck!!

In 'Rescue in the Pacific' - story of the v bad storm in 1994 (?) they measured consistently waves in the 100ft region - measured by aircraft fitted with gear which could do this accurately.

I mentioned this book for reading some days or weeks ago (cant remember, they go so fast) - it is grippingly written and I recommend it to anyone.

<hr width=100% size=1>Black Sugar - the sweetest of all
 
Measure wave height and divide by two

My understanding of the 'official' way that wave height is measured is not from trough to peak, but from the mean level to peak. Thus, if there is an 'official' measurement of a wave at 100 feet, the actual trough:crest distance will be 200 feet.

Can anyone confirm whether I'm right?

<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>
 
Re: Measure wave height and divide by two

The NOAA site says that it's measured from trough to peak. It also offers the rule of thumb that max wave height in feet is half the wind speed in mph, so a 100 ft wave indicates a wind speed over 180 knots; though I guess that interference effects may lead to much higher levels.

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Re: Measure wave height and divide by two

You're not thinking (perhaps!) of "significant" wave height...?

"Significant wave height, Hsig, is the average height (from wave crest to trough) of the one-third highest waves at a location during a wave measurement time period."

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Re: on the same line!!

Isaac's storm
the sinking of Galveston
describes seas of incredible intensity and HUGE waves
factual accounts abound
not a sailing book more met based

<hr width=100% size=1><font color=red>if guinness is good for you. i must be very very good</font color=red>
 
Re: Flippin\' eck!!

Thanks Nicho. Due to you I've just spent 10 minutes fighting with the contents of a wheelie bin!

How did I know there was an interesting supplement in this months copy. I just haul the magazine out, and chuck the plastic and usually junk mail contents away. Doh!

Anyway, the plastic kept it clean, and I've now recovered it, and am deeply engrossed in the tales of heroism

<hr width=100% size=1> I asked an economist for her phone number....and she gave me an estimate
 
Re: Measure wave height and divide by two

Sounds a bit generous to me - 2 metre seas in 10 knots of breeze? To me that is as close to calm as makes no difference, usually!

Looking at the <A target="_blank" HREF=http://www.ndbc.noaa.gov/station_page.phtml?$station=62103>Channel Buoy</A> figures for the last few days implies 1/3 to 1/4 is nearer the mark. Maybe the NOAA figure only works in open ocean, steady state winds (when was the wind last steady?).

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Re: Measure wave height and divide by two

i've passed 62103 but not leant over and given her a kick or switched her off and on as per MS Windows 5 but ... the wave heights reported are always lower than what i seem to be experiencing .. i wonder if it produces a single instantaneous data sample every hour or, more likely perhaps, it averages data in which case it'll miss the nasty ones that come along ever so often ..?

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Re: Measure wave height and divide by two

This was the way Adlard Coles calculated them in "Heavy Weather Sailing".

John

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