How do you determine wave size

[PTC]

I keep seeing posts mentioning 3-4 foot waves. I know how I'd measure them. I know I would not be out in a 4' wave (my idea of a 4'). So there must be another way of measuring, and I'm curious what it is.

Thanks!

[Toolman]

I believe that a wave is measured from sea level to the top of the crest. Some people measure from the bottom of the trough to the top of crest which gives an exaggerated wave height (probably close to 2x) actual size.

Tim

[Phil T.]

Yup, physicists measure waves from "level" to top of crest or bottom of trough. The weather service commonly measures from peak to trough, which is 2X the other measurement. Boaters not used to rough water, or desiring to boast about their boat, commonly double the weather service measurement.

[PTC]

>Boaters not used to rough water, or desiring to boast about
>their boat, commonly double the weather service measurement.

That is pretty much what I figured. Either it was that, or there was some other method of measuring; i.e. space between waves, distance from crest to crest, etc. I just can't see any walleye boat running comfortably at WOT over waves that were cresting 4' above water level.

[boat nut]

There are a variety of techniques used. NOAA measures from the trough to the peak. Here's a link with some descriptions:

http://surfing.about.com/library/weekly/aa042001.htm

[Jawjerker]

To measure wave height, I just use the graph on my locator. Not very tough, you can see how much the boat bounces up & down and measure it.

Good luck

[Badger 05]

I have done that also but I don't think that is accurate either as your boat rises to the top of the wave and than falls to the bottom of the trough. You could watch your graph and divide that in half to get an accurate number. I agree with the original poster that people exaggerate wave size. I saw 6 foot waves once while I was on a lake and a storm came up unexpectedly. The wind was blowing 50mph in the perfect direction to make the largest waves. We were barely able to move above throttle speed in a Pro-V and ended up zig zagging across the waves to a safe area because we were afraid the boat may capsize. I never want to see that again. I think the waves were about 10-12 foot from crest to bottom of the trough on the graph.

Fishing is: One jerk waiting for another jerk at the end of his line.

[rickn]

when thet clear the bow, they're too big!

[REW]

Rick is right on.
If you take 500 gallons of water over the bow or side of the boat and sink, the waves were too high.

If you are going carefully, and spear a wave and take 1000 gallons of water over the bow, and sink - they are too high.

If you are going too slowly, and take a following wave over the stern and take 2000 gallons of water over the stern and sink, they are too big.

If you are going too fast, and nose into the bottom of a trough and pitch pole, by flipping over upside down and sink, they are too big.

So -
If you can stay on top of the water and get safely home - it really doesn't matter how big the waves are.

If you stumble over a 6 inch wave and sink, they were too big.

Above all - know your limitations. Know the limitations of your boat.
Always put safety before fishing.
Always put safety before even the comfort of your passengers.
If in doubt - get off the water.

Above all - respect Mother nature - SHE ALWAYS - knows best!!

Be safe and have a wonderful boating season.

Take care
REW

[Gray Ghost]

Here's how I determine wave size: listen to what people are saying is the wave size, then cut it at least in half. People are chronic exaggerators on wave size. In most walleye boats, a true 2-3' wave will be enough to knock your teeth out unless you drive very very carefully. I generally won't go out in my 20' in over what I consider to be 3' waves, and even then I know it won't be very much fun.

GG

[Jayman]

I kind of agree with Grey Ghost. I think most people exaggerate way too much. I remember someone saying they were out in 6'ers and never even got wet. obviously a spiel about how great there boat was. I was once out in waves I would consider 6', from trough to crest in an 18' on GB, and to be quite honest, I never want to be in waves like that again.

Like stated before, saftey should be #1 priority.

[kliph]

I think when my boat is going up the face of a 6 foot wave, it`s a 6 foot wave.
You measure a wave top of crest to bottom of trough. It`s how far
the boat travels. It`s not a sine wave. It`s a water wave. :)

[Netminder]

I have posted this before but here it is again for those that missed it.

I found the navy definition of "Wave Height at the following site. https://www.advancement.cnet.navy.mil/products/web-pdf/tramans/bookchunks/14269_ch1.pdf
The following is their definition, which from my experience as a sound testing specialist is accurate. If you go to page 46 you will find the fig. 1-31 they refer to.

"In oceanography, wave height (fig. 1-31) is the vertical distance, usually measured in feet, from the crest of a wave (the highest portion of a wave) to the trough of the wave (the lowest portion of the wave). This differs from the "wave height" or "amplitude" normally used in physics, in which the distance is measured from the "at rest" or midline position to the crests and troughs. When waves are generated by the force of wind acting on the water, the wind speed determines the maximum height of the wave. For a given wind speed, many different wave lengths"



Netminder

"Learn from the mistakes of others, because you won't live long enough to make them all yourself"

[HumorMan]

Now, REW, there you go again ... being technical and practical. This time you even managed to do it all in the same post.

Jeez. You really take the fun out of doing stupid boating things.