Info Helium is expensive and deep air is not my thing. -Let's talk about "Big" dives.

[Dave Whitlow]

Thanks, @Dave Whitlow. Hmmm. It seems that those on the boat didn't believe that your RMV rate would allow the ~7,400 (= 2 * 16 * 232) liters, or ~260 cu ft, of gas you were carrying in your isoation-manifolded doubles to be of sufficient quantity (including emergency reserves) for you for this planned 65 meter, or ~210 fsw, dive.

They were a dive boat operator and live-aboard offering gas fills, with dive management left entirely to the divers. Their disappointment was the volume of gas I was buying wasn't as much as it could have been. However, at the end of the trip £500 (in 2010) was still a significant gas bill for 6 days diving. I suspect today the cost might be slightly higher....

Diving CCR that volume of gas would last a few years....