Underwater Express - High Speed Troop-Carrying Torpedo
The Underwater Express, a kind of troop-carrying torpedo, is under development by our friends at DARPA. We've all tried swimming as fast as we can underwater - but would you believe 115 miles per hour?
To reach such amazing speeds, the vehicle would need to make use of supercavitation. A bubble of gas is generated around an object, reducing drag and making high speed underwater possible.
The concept has been around for several years, but it surfaced again at DARPATech 2007, held in Anaheim, CA, a few weeks ago.
I can't really call it an sf prediction, but there is an interesting precursor (implementation?) of this idea in the Konami Computer Entertainment game Metal Gear Solid. In the game, a retired soldier infiltrates a nuclear weapons disposal facility to neutralize a terrorist threat.
Check out the one-man SDV (swimmer delivery vehicle), which is a kind of individual Underwater Express.
(Metal Gear Solid SDV [swimmer delivery vehicle])
One can only hope that the Underwater Express will have this cool red-lit interior.