08/09/2026
https://www.rnz.co.nz/news/crime-and-justice/1307924/coroner-calls-on-mbie-to-ban-tankless-diving-device-after-accidental-drowning
OMG, there's so much wrong with this. Please don't buy devices marketed to make your freediving easier. Just a small snorkel, separate from your mask, for surface breathing only please.
1. Never dive alone (can't believe his mates left him alone, even taking the boat away, especially if they understood anything about what he was doing). Please look out for your buddy whenever they are underwater.
2. This is not freediving. We do not breathe under water.
3. Scuba diving (or any breathing of air underwater) requires education. If you don't understanding the basic science of what you're doing, things can go wrong very quickly, and generally with huge consequences (death). And, regardless of whether the airflow is consistent or not, this is incredibly dangerous as too easy to alter your depth in the water.
Basic explanation:
The volume of air decreases as you dive deeper. At 10m underwater it is half the size it was on the surface. At 20m it is a third. This air is in your lungs, your middle air and your blood stream/tissues. If you breathe normally at 10m underwater you will therefore breathe twice as much air as you do on the surface to normalise these volumes. Too long here alters the balance of gases in your body which also has consequences. If you then swim quickly to the surface (as one does when they panic) the volume of air increases rapidly so it will be twice the size on the surface. This will generally release itself from your ears. And it is possible you could exhale to release from your lungs without it forcing itself into your body around your lungs, but it grows in your blood stream and gets stuck around joints in in your brain, stopping blood flow and potentially leading to death. This is why there are strict rules in scuba around coming up very slowly. This does not affect your average freediver as they only take with them the air they breathed on the surface so they can swim up as fast as they want and do not need to exhale (please don't).
The day before he died, Shengwei Cao pulled out his new tankless diving device - a Wolach 919 - and tested it in the bathtub.