Dave,
Please excuse my condescending previous reply to this post. I didn't know
your background.
MMC

"Dave" wrote in message
...
On Wed, 26 Apr 2006 13:41:50 GMT, "MMC" said:

As I remember a Mk 5 diver would be conscious for something like 6
minutes
if he lost his air supply

My recollection is that it would be significantly more than that.
Remember,
we're talking about the time required to reduce the percentage of oxygen
in
the fixed amount of air contained in the suit and hat combined to below a
level that will sustain life. The rig was designed so the if the air hose
where cut completely you could send another diver down with a new hose and
hook it up to the hat. I'd be surprised if that could be done in under 6
minutes except in the most exceptional circumstances.