[bluestar]

Hello, below is a typical NOAA ocean condition forecast. Can you help me decipher what it is saying? The only part I can be sure is the winds part:

SW WINDS 10 KT. WIND WAVES 2 FT OR LESS. NW SWELL 9 TO
12 FT AT 13 SECONDS AND S 3 FT AT 15 SECONDS.

Specifically, I'm wondering:

What is a "wind wave"?
What is a "swell"?
What are all those "seconds" about?
What data is more crucial to boating in the sea?

[AMG]

Are you serious..?

[AlfredZ]

Hi there,

Wind waves are waves generated by winds, swells are waves generated by surface gravitythe seconds are the wave period for swells which is the travel time of the wave group. You have to know all those information so you know what will be slapping your boat harder and from which direction so you can plot the best routes and choose the headings that will be best for your boat, safe and faster to reach your intended destination.

Cheers,
Alfred

[bluestar]

Originally Posted by AMG

Are you serious..?

Absolutely! If you can help that'll be great. Thanks in advance.

[Marmot]

Nobody is born knowing that stuff ...

Download and print this booklet:

http://www.vos.noaa.gov/ObsHB-508/Ob..._compliant.pdf

It has way more then you really need right now and is aimed at the mates on a deep sea ship who provide weather data but the explanations are very clear and easy to understand (they are written for deckies so they have to be simple) and if you take the time to wade through, all your questions will be answered very well.

[saltysenior]

AND S 3 FT AT 15 SECONDS.

never understood that part of the forecast...

[C4ENG]

Originally Posted by AMG

Are you serious..?

I did not exactly understand that either:
WIND WAVES 2 FT OR LESS. NW SWELL 9 TO 12 FT.
What would I expect to see exactly? 2 ft wind waves on top of 12 ft swells?
I think I just might read Marmots link to figure it out as well.

[vivariva]

Aren't the seconds the swell interval, thus increase in height will increase the interim period between the one wave and the next?

It is a mixture of waves generated by different weather at different locations I believe.

[Marmot]

Why not just RTFM?

[saltysenior]

the FM will not download

[Kevin]

It just worked for me.

[AlfredZ]

Originally Posted by saltysenior

the FM will not download

If right-click, save target on the link did not work for you, PM me your email and am more than glad to send it to you.

Cheers,

Alfred

[saltysenior]

finally got it ,but i'll never live long enough to read it all and too old to understand it........

so i'll just ask.....how can a 3 ft. S.[waves] be 15 seconds apart ??? I know if I was hanging on to the local bell buoy for dear life, I would be hit in the face faster than every 15 secs..

[triggerfish23]

Originally Posted by saltysenior

finally got it ,but i'll never live long enough to read it all and too old to understand it........

so i'll just ask.....how can a 3 ft. S.[waves] be 15 seconds apart ??? I know if I was hanging on to the local bell buoy for dear life, I would be hit in the face faster than every 15 secs..

This is the second set of swells. The wind waves don't have a timing listed, but both sets of swells do.

You're right, you'd probably rather not be hanging on to a buoy (probably no matter the conditions)http://www.yachtforums.com/forums/im...ons/icon10.gif

[AlfredZ]

Originally Posted by saltysenior

finally got it ,but i'll never live long enough to read it all and too old to understand it........

so i'll just ask.....how can a 3 ft. S.[waves] be 15 seconds apart ??? I know if I was hanging on to the local bell buoy for dear life, I would be hit in the face faster than every 15 secs..

Good thing you got the PDF.

The speed of a wave set in a swell is three times its period in seconds, so if the period is 15 seconds then the wave speed is 45 knots per hour, which is you might notice now is a big wave set, sets at such size of height, period and speed does not lose energy energy. By this information you can judge the nature of the swells and how frequent they will effect your boyant motion. Surfers take swell information of deep sea into regard because they can tell when the big surf will be coming to shore and what heights and lengths to expect.

Cheers,

Alfred