While never saying never about future scrientific breakthroughs, it is extremely unlikely for the following reasons: Water is an extreme drag factor. Just to push a regular ship through the ocean at only 20kts. (about 24mph) takes thousands of horsepower to simply overcome the drag resistance created by the water against the ship's hull. The speed of sound is not constant but is a variable. The denser a material is the faster the speed of sound is. At seal level in air, the speed of sound is 764mph while at 50,000 feet, the speed of sound is now around 700mph. In much denser water the speed of sound is now up around 798mph +. In distilled water at 77F it is 3,346mph Another variable is the medium sound is travels through also determines its speed but in general suffice it to say that the denser a material is the faster the speed of sound is through it. There's much more to this but the amount of energy needed to push something faster greatly increases and this is accelerated by the density of the medium the craft is going through. Assuming some power source could be created to push a sub to even near sonic speeds in water would mean that the pressure against the hull would be virtually off the scale. Simply it would be far easier to dematerialize the sub in one location and then rematerialize it at it's destination than to try to move it under power to the speed of sound while submerged; or if somehow the sub could be made transparent to the water medium it's in so that there is virtually no resistance from the water and that exists only in the realm of science fiction today and in the foreseeable future.

Technology would be easier to create to teleport the submarine from one place to another than to have it move through the water at supersonic speeds. Another method would be to have a submarine that could fly out of the water; becoming an aircraft capable of going at supersonice speeds, then re-entering the water to cruise both on the surface and submerged at normal sub speeds. There's been a weapon used by US & NATO submarines for the last couple of decades that does just that! It's called SUBROC; it's fired out of a convention torpedo tube; after going a certain distance a rocket motor ignites and the missile angles up to break the surface and then goes supersonic; acquires its target then makes a plunge back into the water at supersonic speeds; slowing down grealy after re-entry into the water; continues to seek it's target. Of course it's one thing for a weapon to be able to perform this feat and quite another for an actual submarine but it's one possible way for a sub to go supersonic.

One that's been decommissioned and is sitting in a museum, yes.

Yes, several. They all seem to have the same smell, which is also found under the lockers of a men's locker room.

Yes --- 2 that have been decommissioned.

Yes! In the Panama Canal zone! It was a military submarine my dad was able to let us tour as kids!

Yes, I've been on a Royal Navy submarine - but only for a visit.

Yes in Malta and hated every second of it. Put me in the air and I am happy, sail me on the sea I am happy but sat below sea level in a small vessel watching fish (which I don't like the look of) swim by, all the time praying that we surface quick and listening to that eerie sonar noise they make - an hour of sheer hell. I went with an ex who wanted to do this and so played loyal gf.

Yep, but not a yellow one. Commissioned and decommissioned. One active/one in a museum. Even the museum one still stank. 100 submariners go down on a mission. 50 couples come up.