I think I've figured out a halfway decent way to do a fairly quick wake effect in Max.
1.) Draw a plane where the wake will go. Slice the waterline. Grid off. Screenshot these.
2.) Import screenshot into PSP. Waterline layer, select waterline, fill white. Gaussian blur the outside ~12 pixels. Blur the whole image.
3.) Paint the wake shape in.
4.) Material with Opacity and Displaceent sharing the same map: Mask, with the drawn map as mask, and a turbulent noise map as the map. Set size to about 0.6 and the Upper threshold to about 0.3.