Wave Height Prediction and Estimation

Levity

A breezy experience last week caused me to seek a method using wind velocity and fetch to predict wave heights. Is there such a formula? A reasonably accurate prediction could help with a go/no go decision.
What is the most accurate method of estimating wave height from the helm?
Seems that the movement of the boat makes fixing wave heights difficult.
Mike 'Levity'

Sea Wolf · Posted: Mon Jun 25, 2007 9:15 pm Post subject:

Mike-

There probably is a predicition formula, but the current would make a huge difference considering how it lays down the waves when it's going with them and stands them up when it opposes them.

I'll bet most folks over-estimate the heights of waves, often by a facor of 2X or more.

Joe.

Sea Wolf · Posted: Mon Jun 25, 2007 9:24 pm Post subject:

Mike-

I looked at the models on wave height prediction- A very complicated subject without easy answers or perfect models!

Check it out:

http://www.google.com/search?hl=en&q=wave+height+prediction+formula&btnG=Google+Search

However, I'll bet you I could design a weighted float with a measuring stick coming up out of it that could be used to gauge the height of passing waves.

Joe.

BrentB · Posted: Mon Jun 25, 2007 9:26 pm Post subject:

You can estimate by determing your height above the waterline.
I am 6'4" and say for example 8" above waterline in the boat at the dock. When in a trough and if you cant see over the crest then waves are over 7'. if you can see over them then less than 7.
m2cw

MOOSE · Posted: Mon Jun 25, 2007 9:27 pm Post subject:

Yes, there is a formula; some of my engineer friends use it to calculate significant wave heights on waterfront projects. It also incorporates duration, for the longer the wind blows at a a certain speed and across a given distance, the bigger the wave. Unfortunately, that's the extent of my knowledge.
Al

rogerbum · Posted: Mon Jun 25, 2007 11:47 pm Post subject:

For swell and wind predictions I use wetsands.com
Their site gives reasonably accurate predictions of swell height and has a 7 day prediction window. Of course, it's more accurate a few days out than it is 7 days out. However, I've found it to be very good. In particular, if you see that there are 3 really low swell days in a row predicted for a couple of days from now. You can almost bank on the middle of those 3 days to be great. Check out the URL and select the region in which you are interested.

JamesTXSD · Posted: Tue Jun 26, 2007 12:29 am Post subject:

Nice site, Roger... wave height, swell, period, and wind. Have you found it to be reasonably accurate for planning purposes a couple days out? I've added that to my favorites! Thumbs Up

I've used NOAA, but this looks better to show trend. Thanks!

Best wishes,
Jim B.

rogerbum · Posted: Tue Jun 26, 2007 7:57 am Post subject: