Fancy That. Turns out, Don Ho was Right All Along. IT is in the Bubbles.

[seaman hornsby]

"Tiny Bubbles", Giant bubbles, all sounds weird to me. Well, You read it and figure it out.

https://www.yahoo.com/news/supercavitation-could-let-submarines-move-161445459.html

[Ralph --- SSBN 598]

There are plenty of articles on this subject.
The one about Iran having a functional super cavitating torpedo is interesting.

Here's an article from 2009

If this sort of thing interests you, here is a link to a long list.

I do not ever see a full size sub having the ability to generate enough gas to sustain a long distance travel.
Small subs or drone subs...maybe.
Russia has had super cavitating torpedoes since the 1970s.
I do not think they have been deployed.
I could be wrong.

It is an interesting idea and I am sure there are people working on it to make it useful or just collect government grant money.

[scott t]

Just strap a hot reactor on the bow to flash the water to steam and bubbles.

[Ralph --- SSBN 598]

See there is a simple solution to this problem.
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Then satellites can follow all the bubble trails in all the oceans.
Who needs sonar!