Really deep rebreathers

[Chuck_Northrup]

I've read a preliminary report which suggests that the cause of death was hypercapnia. The Mark 15.5 has back mounted lungs which when over-filled would make exhalation (and therefore good gas exchange) difficult. This is thought to be what happend to Dave Shaw.

Complications resulting from CO2 retention and increased narcosis at this extreme depth/workload combination brought a tragic end to this difficult operation.