Found a publicly available photo of a real 688 prop on the bottom of this page:
http://http://americanhistory.si.edu.../taming6.html#
On a separate note, how did you add the Walter turbine to the boat? I'd like to throw it on my Skipjack to get it to play a bit more like a real nuke boat.
And does anyone know a way to get better depth control with the fast boats? It's a pain oscillating up and down as the helmsman tries to hit the ordered depth and keeps overshooting.