Wave heights
 

I've been kind of interested in some of the posts about Lake Erie conditions
to see references to 12 foot waves. I know the waves are shorter and steeper
there due to the lighter water and shallow depths. Twelve footers would
considered pretty big however, even on the ocean.

I've been pretty involved in past years with marine safety and accident
investigation projects and this gave me a chance to look into wave height
reports. There is a pretty consistent tendency for even experienced seaman
to over estimate wave heights by about 100 percent.

There is a way to estimate wave height with fair accuracy. I've done it and
then looked at what I know to be six foot waves a minute or two later and
still been unable to convince my brain that I was not looking at twelve
footers. There are some physical as well as perceptual reasons for this.

For reasons that are more psychological, there is also a tendency to
overestimate heel angles by about the same proportion. This has influenced
accident investigations when observations have been accepted as fact.

If you'd like a good sea story, and to get some idea where I'm coming from,
read "Pride of the Sea" by Tom Waldron. My name pops up frequently through
this story of the loss of the "Pride of Baltimore."

A drier, but in some ways more technically interesting book is, "Tall Ships
Down" by Daniel S. Parrott. I also have a couple lines of page numbers after
my name in the index of this book and was involved in the post mortum of
three of the five accidents discussed.

If you saw the History Channel "Deep Sea Detectives" show about the sinking
of the ship that took Admiral Byrd's aircraft to Antarctica, you also saw me
at the end discussing her loading and stability.

I just mention these things because I'll be pretty active in this news group
now that I'm getting back into sailing and cruising and people may as well
know who I am.

--

Roger Long

Welcome back, Roger. Glad to have you here. Wait around a bit and hoary will
tell you of the 40 foot waves menancing Annapolis.

I've been kind of interested in some of the posts about Lake Erie conditions
to see references to 12 foot waves. I know the waves are shorter and steeper
there due to the lighter water and shallow depths. Twelve footers would
considered pretty big however, even on the ocean.

I've been pretty involved in past years with marine safety and accident
investigation projects and this gave me a chance to look into wave height
reports. There is a pretty consistent tendency for even experienced seaman
to over estimate wave heights by about 100 percent.

There is a way to estimate wave height with fair accuracy. I've done it and
then looked at what I know to be six foot waves a minute or two later and
still been unable to convince my brain that I was not looking at twelve
footers. There are some physical as well as perceptual reasons for this.

For reasons that are more psychological, there is also a tendency to
overestimate heel angles by about the same proportion. This has influenced
accident investigations when observations have been accepted as fact.

If you'd like a good sea story, and to get some idea where I'm coming from,
read "Pride of the Sea" by Tom Waldron. My name pops up frequently through
this story of the loss of the "Pride of Baltimore."

A drier, but in some ways more technically interesting book is, "Tall Ships
Down" by Daniel S. Parrott. I also have a couple lines of page numbers after
my name in the index of this book and was involved in the post mortum of
three of the five accidents discussed.

If you saw the History Channel "Deep Sea Detectives" show about the sinking
of the ship that took Admiral Byrd's aircraft to Antarctica, you also saw me
at the end discussing her loading and stability.

I just mention these things because I'll be pretty active in this news group
now that I'm getting back into sailing and cruising and people may as well
know who I am.

--

Roger Long

WaIIy wrote:
On Sun, 19 Dec 2004 17:56:54 GMT, "Roger Long"
wrote:


I've been kind of interested in some of the posts about Lake Erie conditions
to see references to 12 foot waves. I know the waves are shorter and steeper
there due to the lighter water and shallow depths. Twelve footers would
considered pretty big however, even on the ocean.

I've been pretty involved in past years with marine safety and accident
investigation projects and this gave me a chance to look into wave height
reports. There is a pretty consistent tendency for even experienced seaman
to over estimate wave heights by about 100 percent.


I lived on Lake Erie (near Cleveland) for 6 years and near the lake for
50 years and have never see or reliably heard of 12 footers.

The highest I have been in are 7- 8 footers and wouldn't like to do that
again.

....

But, if there are a lot of 7-8 waves in a confused pattern, wouldn't
that mean that on occasion there would be a 10 footer from constructive
interference? IIRC, Van Dorn has a chapter in predicting the frequency
of wave heights. If the "significant wave height" is 8 feet, then there
will be some 10-12 footers.

In article , WaIIy To wrote:


On Sun, 19 Dec 2004 17:56:54 GMT, "Roger Long"
wrote:

I've been kind of interested in some of the posts about Lake Erie conditions
to see references to 12 foot waves. I know the waves are shorter and steeper
there due to the lighter water and shallow depths. Twelve footers would
considered pretty big however, even on the ocean.

I've been pretty involved in past years with marine safety and accident
investigation projects and this gave me a chance to look into wave height
reports. There is a pretty consistent tendency for even experienced seaman
to over estimate wave heights by about 100 percent.

I lived on Lake Erie (near Cleveland) for 6 years and near the lake for
50 years and have never see or reliably heard of 12 footers.

The highest I have been in are 7- 8 footers and wouldn't like to do that
again.

Lake Erie is notorious due to the closeness of the waves. Everything
is a chop 1ft-2ft-6ft chop.

Of course, when it is rolling or fairly flat, it's wonderful (if quite
brown).

I grew up on the northwest end of Lake Erie and was out on it frequently in
my younger days.

It wasn't dangerous so much for wave height as short period. I've been on
it in 6 footers that felt like they were on a 2 second period, and did
similar things to the boat. It was NOT fun.

--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME!
http://genesis3.blogspot.com Musings Of A Sentient Mind

In article ,
Jeff Morris wrote:


WaIIy wrote:
On Sun, 19 Dec 2004 17:56:54 GMT, "Roger Long"
wrote:


I've been kind of interested in some of the posts about Lake Erie conditions
to see references to 12 foot waves. I know the waves are shorter and steeper
there due to the lighter water and shallow depths. Twelve footers would
considered pretty big however, even on the ocean.

I've been pretty involved in past years with marine safety and accident
investigation projects and this gave me a chance to look into wave height
reports. There is a pretty consistent tendency for even experienced seaman
to over estimate wave heights by about 100 percent.


I lived on Lake Erie (near Cleveland) for 6 years and near the lake for
50 years and have never see or reliably heard of 12 footers.

The highest I have been in are 7- 8 footers and wouldn't like to do that
again.

...

But, if there are a lot of 7-8 waves in a confused pattern, wouldn't
that mean that on occasion there would be a 10 footer from constructive
interference? IIRC, Van Dorn has a chapter in predicting the frequency
of wave heights. If the "significant wave height" is 8 feet, then there
will be some 10-12 footers.

Yep.

I did the crossing from Clearwater to Appalachicola in 6-8s a couple of
years ago, and there were definitely some 10s and a couple of 12s in there.

The latter were easily identified - the crests were well above my sight line,
which is roughly 16' off the water.

That crossing sucked.

--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME!
http://genesis3.blogspot.com Musings Of A Sentient Mind

jeffies, knock it off. if you don't understand the meaning of the term "wave
height" get your wife to explain it to you. stop argueing with two guys who
clearly do know what the term means.

From: Jeff Morris
Date: 12/19/2004 2:36 PM Eastern Standard Time
Message-id:

WaIIy wrote:
On Sun, 19 Dec 2004 17:56:54 GMT, "Roger Long"
wrote:


I've been kind of interested in some of the posts about Lake Erie
conditions
to see references to 12 foot waves. I know the waves are shorter and
steeper
there due to the lighter water and shallow depths. Twelve footers would
considered pretty big however, even on the ocean.

I've been pretty involved in past years with marine safety and accident
investigation projects and this gave me a chance to look into wave height
reports. There is a pretty consistent tendency for even experienced seaman
to over estimate wave heights by about 100 percent.


I lived on Lake Erie (near Cleveland) for 6 years and near the lake for
50 years and have never see or reliably heard of 12 footers.

The highest I have been in are 7- 8 footers and wouldn't like to do that
again.

...

But, if there are a lot of 7-8 waves in a confused pattern, wouldn't
that mean that on occasion there would be a 10 footer from constructive
interference? IIRC, Van Dorn has a chapter in predicting the frequency
of wave heights. If the "significant wave height" is 8 feet, then there
will be some 10-12 footers.

Thanks for admitting up front you have no understanding what we're
talking about. This saves a lot of time. Now shut up before you
embarrass yourself again.


JAXAshby wrote:
jeffies, knock it off. if you don't understand the meaning of the term "wave
height" get your wife to explain it to you. stop argueing with two guys who
clearly do know what the term means.


From: Jeff Morris
Date: 12/19/2004 2:36 PM Eastern Standard Time
Message-id:

WaIIy wrote:

On Sun, 19 Dec 2004 17:56:54 GMT, "Roger Long"
wrote:



I've been kind of interested in some of the posts about Lake Erie

conditions

to see references to 12 foot waves. I know the waves are shorter and

steeper

there due to the lighter water and shallow depths. Twelve footers would
considered pretty big however, even on the ocean.

I've been pretty involved in past years with marine safety and accident
investigation projects and this gave me a chance to look into wave height
reports. There is a pretty consistent tendency for even experienced seaman
to over estimate wave heights by about 100 percent.


I lived on Lake Erie (near Cleveland) for 6 years and near the lake for
50 years and have never see or reliably heard of 12 footers.

The highest I have been in are 7- 8 footers and wouldn't like to do that
again.


...

But, if there are a lot of 7-8 waves in a confused pattern, wouldn't
that mean that on occasion there would be a 10 footer from constructive
interference? IIRC, Van Dorn has a chapter in predicting the frequency
of wave heights. If the "significant wave height" is 8 feet, then there
will be some 10-12 footers.

jeffies, do check with your wife. tell you what you believe the term means,
and let her help you out. if she is patient, maybe you can come back here
better informed. if she is sick and tired of your antics she may tell you to
sit in the corner for a while.

btw, jeffies, you have already told the two newcomers you don't have a clew
what you are talking about re wave height but that you are more than insistent
that you do. way to go, dog pile. way to go.


From: Jeff Morris
Date: 12/19/2004 3:48 PM Eastern Standard Time
Message-id:

Thanks for admitting up front you have no understanding what we're
talking about. This saves a lot of time. Now shut up before you
embarrass yourself again.


JAXAshby wrote:
jeffies, knock it off. if you don't understand the meaning of the term
"wave
height" get your wife to explain it to you. stop argueing with two guys
who
clearly do know what the term means.


From: Jeff Morris
Date: 12/19/2004 2:36 PM Eastern Standard Time
Message-id:

WaIIy wrote:

On Sun, 19 Dec 2004 17:56:54 GMT, "Roger Long"
wrote:



I've been kind of interested in some of the posts about Lake Erie

conditions

to see references to 12 foot waves. I know the waves are shorter and

steeper

there due to the lighter water and shallow depths. Twelve footers would
considered pretty big however, even on the ocean.

I've been pretty involved in past years with marine safety and accident
investigation projects and this gave me a chance to look into wave height

reports. There is a pretty consistent tendency for even experienced
seaman
to over estimate wave heights by about 100 percent.


I lived on Lake Erie (near Cleveland) for 6 years and near the lake for
50 years and have never see or reliably heard of 12 footers.

The highest I have been in are 7- 8 footers and wouldn't like to do that
again.


...

But, if there are a lot of 7-8 waves in a confused pattern, wouldn't
that mean that on occasion there would be a 10 footer from constructive
interference? IIRC, Van Dorn has a chapter in predicting the frequency
of wave heights. If the "significant wave height" is 8 feet, then there
will be some 10-12 footers.

Twelve footers would considered pretty big however, even on the ocean.

ROFL!

What's this fetish you have with my wife you have, jaxie? More of your
jealousy showing? Do we need a restraining order?


JAXAshby wrote:
jeffies, do check with your wife. tell you what you believe the term means,
and let her help you out. if she is patient, maybe you can come back here
better informed. if she is sick and tired of your antics she may tell you to
sit in the corner for a while.

btw, jeffies, you have already told the two newcomers you don't have a clew
what you are talking about re wave height but that you are more than insistent
that you do. way to go, dog pile. way to go.



From: Jeff Morris
Date: 12/19/2004 3:48 PM Eastern Standard Time
Message-id:

Thanks for admitting up front you have no understanding what we're
talking about. This saves a lot of time. Now shut up before you
embarrass yourself again.


JAXAshby wrote:

jeffies, knock it off. if you don't understand the meaning of the term

"wave

height" get your wife to explain it to you. stop argueing with two guys

who

clearly do know what the term means.



From: Jeff Morris
Date: 12/19/2004 2:36 PM Eastern Standard Time
Message-id:

WaIIy wrote:


On Sun, 19 Dec 2004 17:56:54 GMT, "Roger Long"
wrote:




I've been kind of interested in some of the posts about Lake Erie

conditions


to see references to 12 foot waves. I know the waves are shorter and

steeper


there due to the lighter water and shallow depths. Twelve footers would
considered pretty big however, even on the ocean.

I've been pretty involved in past years with marine safety and accident
investigation projects and this gave me a chance to look into wave height

reports. There is a pretty consistent tendency for even experienced

seaman

to over estimate wave heights by about 100 percent.


I lived on Lake Erie (near Cleveland) for 6 years and near the lake for
50 years and have never see or reliably heard of 12 footers.

The highest I have been in are 7- 8 footers and wouldn't like to do that
again.


...

But, if there are a lot of 7-8 waves in a confused pattern, wouldn't
that mean that on occasion there would be a 10 footer from constructive
interference? IIRC, Van Dorn has a chapter in predicting the frequency
of wave heights. If the "significant wave height" is 8 feet, then there
will be some 10-12 footers.