The Homemade Submarine (1999) (opens in new tab)

He has a new sub; here’s some photos I found of the C-bug from before and after it was retired.

http://vulcaniasubmarine.com/KARL%20STANLEY.htm

His web site; seems to still be doing tours, but now down to 3000 feet!

http://www.stanleysubmarines.com/

I'd be so nervous about getting wrecked by a soliton being in something like that.

https://link.springer.com/article/10.1007/s13131-021-1893-0