The person is most likely correct much as a lighting bolt and its branches are fractal but I don't think a fractal program would be the best way to model either one. Which rendering program are you using? Chances are someone has already made a bump map for waves. The crest of the bow wave would still be best done with a model. The foam and overspray I would be temped to say use your favorite paint program. Having said that I should also note I am first a modeler and have just started exploring fractals.