[Mal Bridgeman]

Originally Posted by Janos

Using your logic I could argue that all diving should be done in October to February as "every fatality that occured in 2007 happened between March and September"

That's not my logic, though. As you yourself have pointed out there is no denominator data. I would suggest one does not need to mathematically / statistically prove some things to know they are not a good idea.

Originally Posted by Janos

Looking back through the incident reports is a great way to learn from isolated, individual mistakes. The thing I take from the incident you mentioned is to always check your valves are on before you get into the water. But this applies equally to twinsets as side-slung ponies as back-mounted ponies.

My conclusion is different ... you need to train into people, that maintaining a constant knowledge of the gas they have remaining is vital, you make things simple for the new diver by only giving them one source to monitor and you are relentess about OOG procedures so if they screw up then it's an inconvenience.

Mal