Hopefully, you are being sarcastic. That is a picture of doing something on the cheap, which is what the Chinese are good at. How about a sub that can even go down 60-70 feet without popping a leak? He’ll get it right on the 6th or 7th try, maybe - if he survives.
Where I live, by Long Island Sound, there are a number of submarine hobbyists who build their own one man subs that are far superior in construction to that. Norwalk and, I think, Mystic, maritime centers have a couple on display.
There was also an article a few years ago about some guy near New York City who got into all kinds of trouble when he tried to test his replica of the Bushnell sub from the revolutionary war. Harbor police thought he was a terrorist.
Yes I was being sarcastic. I spent years of my life as a nuc on SSNs and my wife worked on subs at the Navy Yard in Vallejo and worked on human powered subs for fun. People in this country used to build stuff like that for fun. Who cares if it works? It looks cool in the front yard. I always liked that boat on the roof in "Ghost Dog". You just don't see that sort of thing attempted here much anymore and if any tried it without approval the government would probably confiscate it.