NavList:

I'm trying to track down some information on the detection of currents in the open ocean.    

I have three sources that discuss the following phenomenon - seasoned navigators are able to tell the set of the current by looking at the shape of waves - they tend to steepen up in the direction of the motion of the current.   So far, I have three sources 1.) A short mention of this in Joshua Slocum's Sailing Alone Around the World, 2.) First hand interview with a Micronesian sailor in The Last Navigator, and 3.) Discussion and interviews by David Lewis in We the Navigators.

The issue that I'm having some difficulty in understanding how wave shapes could be affected by current in the open ocean.   If everything is in a moving frame of reference together, I wouldn't expect any effect on the shape of waves.   The only explanation I could come up with is that there's a stationary layer not too far under that is creating a kind of drag effect which would cause the waves to steepen up.     

So - anyone have any information on this phenomenon, or sources that make conjectures about it?   Any other anecdotal experiences with this?

Thanks!

John Huth