I've read in several reports about ships with propellers in steerable pods that were designed to "crash stop" by turning the pods 90 degrees inward or outward. I don't understand why that works.
Probably because the steerable pods are far less streamlined when turned sideways, and add a huge amount of drag in the water.
http://www.boatnerd.com/pictures/spe...005_0402AO.jpg