Well, it turns out I have my waves all wrong.
Good references for detailing ship's wake are at:
http://www.steelnavy.com/toppage3.htm (http://www.steelnavy.com/toppage3.htm)
I'll work on a new version and detail the steps. By the way, I used acrylic gel medium, as is recommended in several of the steelnavy articles.
Garet
Modern submarine wake:
http://www.flickr.com/photos/usnavynvns/4111853099/
Note that the modern streamlined submarine makes a wake very different from a surface ship.