"I've had to cope with poor visibility, which has at times been nil, I've had to work against the resistance and the pressure of the water.
"You don't know what's underfoot - sometimes its mud, silt, rocks or nothing.
"The airline also kept getting caught and I also had to deal with a build-up of carbon dioxide in the helmet. It's also very cold and very lonely."
In something of an understatement, this guy, quite possibly a lunatic, admitted: "It's definitely been far more difficult doing it underwater than it has been on land."