supercavitating submarine

a submarine expelling gas at the front of the submarine 

to make it supercavitating 

the supercavitation would reduce drag of the submarine 

and make it very fast 

if possible the submarine would be propelled by hydrojet 

that pulls in water from the front or sides of the submarine 

depending on supercavitation 

and pushes water out of the end of the submarine 

if it's a nuclear submarine, then the water could be superheated 

to make the submarine ridiculously fast 

the submarine would be armed with internal miniguns 

that shoots supercavitating bullets through openings in the submarine against incoming torpedoes 

each supercavitating bullet expelling gas in the front of the bullet 

to enable bullets to travel farther underwater 

and the submarine would be armed with torpedoes against enemy vessels 

drone versions of this game changing submarine would be lethal 

especially as dispersed swarms loitering underwater in the seas 

awaiting stimuli or orders to attack