This really should go in an oceanography section, but there doesn't seem to be one ?
I would like confirmation that what I think is a sailors' myth is indeed a myth, not reality.
I'd also like confirmation of an explanation of how the myth came to be, if I am correct.
The "myth" is that wind over water, against a current, will cause shorter wavelength waves. The way it is usually described is that the seas become steeper and rougher.
Since there is no difference between a 3 kt current against a 10 kt wind and a 0 kt current against a 13 kt wind, the steeper seas can not be caused by the current against the wind. My assumption is that the "observed" phenomena is not just caused by the 3 kt relative increase in wind over what would be observed if the current wasn't moving.
My suspicion is that the steeper seas are caused by waves which are formed outside the current but which enter into the current, moving against it. The relative wave speed outside the current and inside the current would go from higher to lower which would indeed cause the wave amplitude to increase as the wave slows down, just as it does when feeling bottom when it approaches a shore.
Confirmation or corrections would be appreciated.