Cavitating torpedoes.... actually, seems to me that a strong enough pressure wave from an underwater explosion (depth charge) would collapse all or a part of the bubble. That's a hell of a G load to put on anything, I doubt the torpedo would survive a decavitation at speed unscatched.
And besides, with the tech common knowledge now, how long would it seriously take to develop a countermeasure? Even something as "off the wall" as a supercavitating sea-entering missile?
