Watching that video, Control’s voice is very clear, but both the diver and the sailor sound like they’re on helium. I’m guessing that’s not an artifact of the recording, whomever’s on Control needs to be able to decipher helium-voice. Is that correct?
I don’t know… seems to me that death by gradual asphyxiation because the oxygen level has become too low would be something akin to dying relatively peacefully from carbon monoxide poisoning, but dying by sucking in lungfuls of water (drowning) would be something akin to… pure hell.
ETA: Looks like this was addressed above.
Sometimes divers do breathe trimix, a blend of gas that includes helium, though not usually at the depths of this incident. This can result in the diver’s voice being shifted up to a higher pitch. Electrical transcoders can help adjust the diver’s voice so it is more intelligible to surface support.
That is incredible video. If the link fails, just search for Jascom 4.
Shudder. How incredible. The instructor topside hardly misses a beat does he?
Given that he was 30 meters down, the ambient pressure was 4 atmospheres (as opposed to 1 atmosphere when floating at the surface), so for a given volume of space, he had 4x as much oxygen available as he would have at the surface. So at the outset, every cubic meter of airspace would have 4x20% = 0.8 standard-cubic-meters of oxygen available.
Metabolic equivalent oxygen consumption is 3.5 ml/min/kg, so for a 100-kg man (he looked heavy in the video), that’s 350 ml/min, or 0.504 standard-cubic-meters of oxygen per day for a 2.5-day total of 1.26 standard-cubic-meters of oxygen. If we assume he starts running into trouble when the oxygen density reaches the equivalent of 20,000 feet up on a mountainside (0.092 actual cubic meters of oxygen per cubic meter of air), then to survive 2.5 days at that depth, he’d need just 1.77 cubic meters of space. Looking at the video, it appears he had at least that.
I’m at a loss to explain how he didn’t kill himself with CO2 buildup, other than that it must have been dissolving into the water fast enough to keep the airborne concentration at a safe level.
Jascon 4.
It’s the theme from “The Great Escape.”
Or click here.