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  #11  
Old 11-06-2012
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Re: Why Waves Look Bigger From a Boat

Quote:
Originally Posted by JulieMor View Post
....so Walbridge may have experienced a wave 70' high in 98 knot winds.
In the same testimony, he claimed to ride those 70 ft waves like he was standing on the ship at the dock. Even if you assume they were so far apart that you might gently roll over them (still ridiculously unlikely), the wind necessary to create them would try to take you off your feet.

Bottom line is, what he said just could not be true.

Why he would say it is probably at the root of this entire calamity.
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Re: Why Waves Look Bigger From a Boat

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Originally Posted by JulieMor View Post
I'm not sure if Walbridge was referring to continuous wave heights when he mentioned 70 feet or if he was referring to a rogue wave.
I am and I think you will be too if you watch the video:

HMS Bounty - YouTube

I've seen two rogues, one of which put a 105 foot schooner so far under water that just the two masts were sticking out of the ocean. They are very dramatic. You look out at the horizon and all the waves are going up and down but one isn't. It just hangs against the skyline like an island until you are suddenly looking into the huge hole in the ocean ahead of it. It is this deep trough that does as much damage as the crest in most cases. I remember looking over the bow of the schooner and seeing the keel dry back to the foremast before she basically sailed dropped and dove into the crest.

Rogue waves are such dramatic and infrequent events that I'm sure he would have described it as such instead of going on about how easily the ship was riding in wave after wave.

Waves are officially reported and forecast by "Significant Wave Height" which is the mean of the largest 1/3 of waves. This graph shows the distribution:



Note that wave height runs along the horizontal axis. Most waves are smaller than the nominal height but a few can be up to twice as large. I could believe the captain of the Bounty if he said, "We saw A 70 foot wave.", but not when he talks many 70 foot waves easily. I have no doubt however that the waves appeared to be 70 feet high to him and that he sincerely believed they were.
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Re: Why Waves Look Bigger From a Boat

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In those sea conditions, that boat should have reefed by now.
Not on the s/v BFS
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Old 11-06-2012
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Re: Why Waves Look Bigger From a Boat

A related phenomenon is why waves look so flat in photographs. I presume this has to do with a frame reference problem, in that, you don't know where the horizon is in a photo.
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Re: Why Waves Look Bigger From a Boat

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Originally Posted by Minnewaska View Post
Why he would say it is probably at the root of this entire calamity.
Sadly, I've thought that too...
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Old 11-06-2012
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Re: Why Waves Look Bigger From a Boat

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Originally Posted by Barquito View Post
A related phenomenon is why waves look so flat in photographs. I presume this has to do with a frame reference problem, in that, you don't know where the horizon is in a photo.
Maybe what we need is a reference table of Actual Wave Height vs Perceived Wave Height.

If Roger's original post is correct, it should be possible to work this out empirically.. Roger?
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Re: Why Waves Look Bigger From a Boat

Quote:
Originally Posted by Hartley18 View Post
Maybe what we need is a reference table of Actual Wave Height vs Perceived Wave Height.
If you are looking at the waves, just ask yourself how high they look and then divide by 2. You'll be close enough for such a fuzzy number.

If anyone says they were out in XX foot waves and you know they are reporting a visual estimate, just divide by 2. If they are in a bar, divide by 4.

Oh yes, divide all the wave heights in the book "Perfect Storm" by two as well. I was at first disappointed that the author didn't research and get this right. I then realized that the book is about the experiences of the people. They experienced waves that were twice as high as a proper measurement would show so I think the book is find. The movie then took those waves and doubled them again but that's Hollywood.

BTW, my former boss did the last stability test and analysis on the Andrea Gail. I asked him after the book came out what he thought happened and he said, "They never saw the storm. That piece of **** would have rolled over long before the real weather got there."

Last edited by Roger Long; 11-06-2012 at 09:11 PM.
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