The American Supercav and the Russian VA-111 Shkval are both high-speed supercavitating torpedoes, 250 mph class (more recently, there are also the English MK70 SpearFish TL8 and the German Barracuda). They don't use blade propellers to move, but powerful powder rocket motors. A fewer part of the generated hot gas is also projected in a front outlet on their nozzle, and the water in contact is vaporized, surronding the entire body, creating very low drag, thus high speed capabilities.
Russia has sold about 40 Shkval-E to China in the 90's.
http://www.periscope.ucg.com/mdb-smpl/weapons/minetorp/torpedo/w0004768.shtml
But think this is old tech: Shkval is more than thirty years old... Its developement program began at Soviet Research Institute NII-24 in the 60's, and a LOT of work, completly different, has since been done. In particular with magnetohydrodynamic torpedoes, made in the 80's, that literally suck water amount of the body and all along of it, with strong electromagnetic forces.
The Russian MHD torpedo codename would be translated in English as "the Big One" or "the Fat One".
MHD torpedoes can travel at very high speed under water such as 1700 mph, because drag is not just reduced as supercavs, but completely eliminated. The drag is even negative, providing up to 70% of thrust thanks to MHD apsiration (around 30% provided by the rocket engine).
MHD propulsion requires large amount of electric power, and the very clever idea of these torpedoes lays in the way how the current is generated: they don't stock it in batteries, nor any capacitors. They create it in situ, extracting electric charges from the exhaust hot (very hot) gas, with an efficient MHD converter that relies on electrodes and magnetic coils. Due to the temperature, the whole system has a very short lifespan (10 seconds or so) but who cares since with such ultra speed you need 3 to 6 seconds to destroy submarine nuclear platforms ? The enemy just cannot react quickly enough.
Now, think that US Navy has since replaced copper coils by superconducting coils, and you can imagine where they are today. Think that the limit is the sound barrier under water and that this speed, unlike in air, is... 3315 mph.