This is coolbert:
Here more on cavitation and super-cavitation.
"Shanghai to San Francisco in 100 minutes by Chinese supersonic submarine"
"Chinese eye 'supercavitation' technology as future of underwater travel"
"China has moved a step closer to creating a supersonic submarine that could travel from
Shanghai to San Francisco in less than two hours."
"New technology developed by a team of scientists at Harbin Institute of Technology's Complex
Flow and Heat Transfer Lab has made it easier for a submarine, or torpedo, to travel at extremely high speeds underwater."
. . . .
"However, during the cold war, the Soviet military developed a technology calledsupercavitation, which involves enveloping a submerged vessel inside an air bubble to avoid problems caused by water drag."
"A Soviet supercavitation torpedo called Shakval was able to reach a speed of 370km/h or more-much faster than any other conventional torpedoes."
That Shakval ONLY good at close range and is designed to deliver an atomic warhead. AND according to American submariners easy to avoid.
Pie in the sky stuff the feasibility and utility thereof very questionable. At least for now.