On the same day, I was reading a book in which there was a short annectdote about someone in the early stages of the nuclear testing program in which they drilled a borehole, dropped a small atomic bomb down it, and covered the hole with a 1/2 tom metal plate. Apparently, they have one frame of the plate on film, which causes them to beleive that the plate was not vaporized. But they don't have two frames, which causes them to beleive that the plate was moving fast enough to leave the field of view in one 1/160th of a second. They don't show the math, but this leads them to conclude that said plate was moving at several times escape velocity.
A third seemingly unrelated event in my distant past involved a coastal lobsterboat in Maine. Someone (else, again unnamed) drained his fuel tank into the bilge when beaching the boat. No, I don't know why. In any case, when he launched the the boat again, it wouldn't start. So he leaned into the cabin and wiggled the battery cable. At which point, the boat promptly blew up. Everyone lived, but the salient detail is that the boat split right along the keel, *down to the waterline, but not below*. The boat thus didn't sink, although it was totalled. Because water is incompressible.
So, finally I'm thinking about the amount of effort people seem to put into building really big cannons, for dropping bombs on their neighbors, or launching robust payloads into LEO, or blasting clouds of sand into the sky to munch satellites. And I can't help wondering why one can't just take a large schedule 160 steel pipe of appropriate diameter, sink one end of it into a convenient lake, pack it with the explosive of your choice and a projectile, set the sucker off, and collect the dead fish for dinner. Sure, you'd probably only be able to use each tube once, but they're a standard industrial product, available in 40' lengths out of a catalogue.
Related questions: Is a cornstarch/water mix stiffer than water at the pressures/and speeds we're talking about? How do you calculate how MUCH water you need around the launch tube? --Goedjn