Determining wave hieght with a depth sounder

[Steve Laume]

I have just started reading Ten hours until dawn, by Michael Tougias. It is a rescue/survival story during the blizzard of 78 off the MASS coast. A great read so far. Kind of like the Perfect storm only closer to shore with more factual information about what acctualy happened. At one point they mentioned that the depth sounder was not working and they were trying to determine wave height at the same time. I may have been reading something into the sentence but it seemed like the two were linked. My hopefully worthy question: can wave height be accurately determined with a depth sounder? I know it would not work in choppy seas. I am thinking about large ocean waves or swells that would allow you to run broad side in the troths, to get to the bottom of things, so to speak. With a flat bottom you could measure the wave height by the difference in depth readings. Did I just wake up, this being common practice? Would it work or am I all wet? Great book anyway, Steve.

[Oswego John]

Hi Steve,

Your post is worthy from where I sit. Sorta makes me think.

I don't ask if this is THE way to determine wave heights. I'm wondering if this is ONE of the methods to determine them?

If so, how do you think that this is done? Would you measure the heights of the crest and the trough and then divide that difference in half to arrive at a mean average or wave height?

It seems that back in time, I read something about satellites somehow recording sea conditions. I don't know if wave heights were included in this process.

Just wondering,
O J

[Parfait's Provider]

Indeed, the forecasters use satellite measurement. See http://www.oceanweather.com/forecast/About/index.html

[Russell]

Most of the time when I am concerned about wave height the water is far too deep for the depth sounder to even tell me anything.

[M. R. Bober]

Try this URL. Most the of buoys report wave height.

Mitchell Bober
Sunny Annapolis (Within easy driving distance of the FAMOUS Groundhog Extravaganza), MD

http://www.ndbc.noaa.gov/

[Neil Gordon]

Interesting, but I have a question. Other than as the baseline from which you can increase the height each time you retell the story to your grandchildren, and so that you know how scared you should be, is there any practical purpose to knowing the height of waves you're already out in?

[Tod Mills]

measure wave height? My guess is that it is some sort of inertial device rather than a sonar, because it would provide a more continuous feedback than pulsing sonar, which would be difficult if not impossible to tie to wave crests/troughs. And some sort of adjustment would need to be incorporated to account for the changing waterline on the vessel (bouy, boat) when on a crest vs. in a trough.

[winthrop fisher]

hey ever one.
i never heard that before.
but we do have sail boats, right....
i have all was look at the mast to get the roughed height.
if you have done that many times, you get pretty good at it...
winthrop

[Neil Gordon]

... look at the mast to get the roughed height.

Winthrop is right.

Climb to the top of the mast. If you're still looking up at the waves, you're in major trouble.

[Joe Myerson]

I'm afraid I can't add anything to the wave-height discussion, but if you're looking to read a great nonfiction book about some heroic mariners (and the horrendous Blizzard of 1978), by all means read Michael Tougias' book. I couldn't put it down.

--Joe

[Russell]

Interesting, but I have a question. Other than as the baseline from which you can increase the height each time you retell the story to your grandchildren, and so that you know how scared you should be, is there any practical purpose to knowing the height of waves you're already out in?

I always record wave height in my log book, useful? maybe not. But if your on a passage and checking in with someone like Herb it helps him to know accurate sea states.

[winthrop fisher]

you are so funny

... look at the mast to get the roughed height.

Winthrop is right.

Climb to the top of the mast. If you're still looking up at the waves, you're in major trouble.