>Table 1 compares the Oceaneering 250-feet profile to two technical open-circuit mixed-gas dives using Global Underwater Explorers (GUE) standard gases for comparison purposes; one dive was conducted in a cave with three decompression gases, the other dive was in open water with two gases. Unlike Oceaneering, technical divers primarily use trimix (an oxygen, helium and nitrogen mix) as bottom gas for open-circuit diving due to the expense of helium, which can cost up to $1.70 to $2.75 per cubic foot, depending on location.
>Note that the Oceaneering profile mandates slightly more than 100 minutes of extra oxygen decompression in comparison to the tech dives. It also runs a higher PO2
during decompression (i.e., switching to nitrox 50/50 at 90 ft, PO2
=1.86 ATA), as the diver is wearing a helmet, not a mask, and will not drown in the event of a convulsion.
>© Alert Diver
— Q3 Summer 2018