Wave height

[rslotpole]

I’m sailing a 40 foot sailboat through waves of 6 feet every 9 seconds for 4 hours. How rough will the trip be? I’ve used 1 sec per foot of wave but not sure this will hold up in 6 feet

[Montanan]

The wave height of a surface wave is the difference between the elevations of a crest and a neighboring trough.

So six feet indicates three feet upward and then three feet downward.

Waves have lengths and also have velocity / periodicity, e.g., 9 seconds.

You could be riding a moderate elevator up to 1,600 times during your 4 hour trip if not moving through the water [not making way], that is to say, the waves traveling under you, e.g. moored. Depending on your direction of travel you will interact with the waves with different relative periodicity.

As to if that is perceived to be rough well that depends on your direction of travel relative to the waves [into, with, or crosswise] and how your vessel performs under such wave conditions.

[rslotpole]

Thanks. Waves are from 110 and we will travel north

[LakeSuperior]

If you are headed into 6 ft waves in Lake Superior you will be going zero in a 40 ft sailboat.

The 6 ft wave measurement in a weather forecast is the average of the highest 1/3 of the waves (measured from peak to trough.) This is the significant wave height. Consequently, there are waves higher than 6 feet in that sea state.

Most important is the periodicity of the wave train. If they are space far apart in distance (time) i.e. fully developed then 6 ft waves are not so bad. These are typically found on ocean size bodies of water.

On Lake Superior 6 ft wave are rarely fully developed and so are close together making the sides (profile) extremely steep. They have become known as "square waves" and they are not much fun to be out in.

[rslotpole]

We will be traveling from Boston to Manchester. Expect to motor sail

[barnakiel]

Depends on the boat. A long deep narrow will go fine if you ally enough force. But wet.


A light flat will be very wet, very slow and very noisy. No sleep.


b.