I'd like to add my own "thumbs up" to Ray's latest regatta video efforts.
The material on this DVD is a very nice mix of real and model subs, with some very good interviews of r/c sub modelers explaining their creations. The WWII mini subs segment that Tim mentioned is titled "Sneak Craft" and was created just after WWII in 1946 by the U.S. It contains some very nice footage and explanations of the various mini-sub methods used by the Italians, Germans, and British.
With this release being in DVD format, not only can you drop this into your DVD player at home, but you can also watch it on your PC/laptop....great for those of us who travel!