Many would argue Constant No-Fins (CNF) is freediving in its purest form. The discipline is as straightforward as its name. The diver is to reach an announced target depth and make it back to the surface of the water all without using any fins or other forms of propulsion. The only tools available are your own arms and feet.

Kiwi William Trubridge isn’t just good at doing this, he’s set multiple world records in the discipline only to go back and one up himself time and time again; 18 times to be exact. Trubridge’s latest attempt set another world record when he went to Dean’s Blue Hole, Bahamas and dove completely unassisted to a depth of 102 meters (334 feet) in four minutes and two seconds.

“When I grabbed the tag at the bottom there was an initial kind of rush or surge of ‘yeah I’m here at the depth,'” he said after the dive. “And then that thought comes back to you: ‘no I’ve still got to swim 102m back to the surface.’ On the way up I started to feel a little bit of a fade about halfway; the sense of an urge to breathe and hypoxia, low oxygen coming on, and I started to wonder if I might need help from my safety divers. I just tried to kind of stay relaxed and focused and that sensation didn’t get any worse, which is good, and all of a sudden I was kind of close to the surface and realized hey, I was going to be able to make this.”