Ok, real foam stays on the surface and floats around.  Aren't you after a "spray" or something? - I lack the word - but I've seen foam that floats around and wraps up in things.  I've seen it stick to my nets when I've fished, and cling to my gloves.

Could you use a surface replicator to put something with substance on the surface?  It would move with the waves, but not just limited to the crest of the waves - 

Nice video Patrick.

If you want just the wave crests, it would need to be elevation - mentioned earlier - maybe with AG on the elevation channel.  

Can't wait to the see what you come up with.

Never Give Up!