We all dream of venturing into the unknown, though some of us would prefer to do it via the camera on the end of a robot, rather than diving head-first into whatever dangers the not-known has to offer. Not Olivier Feuillette though -- over the course of a few years, he transformed a kayak into a one-man, human-powered submarine.
The video here shows the magnificent creation in operation, but sadly doesn't explain details of its creation. However, the Huffington Post did spot the following comment to the clip, from someone claiming to be Feuillette, regarding how he breathes:
"Air comes from a cylinder, over flow comes out. For long dive co2 filter is used i am talking over 2/3 hours. The pressure is equalized so scuba rules are apply, same for depth."
One of the first submarines was a rowboat with leather wrapped around it, so it's not that far-fetched an invention. That doesn't mean you'd catch me inside it.