It works for torpedos so they may be able to adapt it for larger scale but the amount of energy needed would be enormous. There is also the issue of transitioning from 1200 fps to regular speed. If not done carefully the sudden slow down would plaster the crew against the hull. I wonder if China is working on an inertial dampening system?
> There is also the issue of transitioning from 1200 fps to regular speed.
The speed of sound in water is not 1200 fps; it’s closer to 4879 fps.
The Russian supercavitating torpedoes are powered by liquid-fueled rocket motors. It’d be interesting to see how that mode of propulsion could be scaled-up to work in a manned submarine, considering the amount of fuel it would have to carry.