Filmmaker Rob Stewart dies off Alligator Reef

[kelemvor]

I'm curious why RB's don't just carry three bottles, He, O2 and N, separately. I'm sure there must be a good reason or folks would be doing it.

 

[CuzzA]

there was complacency with more than just the ease of mixing the gas...

Staring from the beginning, perhaps video of sawfish? He shouldn't have been where he was given what we know.

 

[Wookie]

I'm curious why RB's don't just carry three bottles, He, O2 and N, separately. I'm sure there must be a good reason or folks would be doing it.

I know some divers who dive helotrox 10/90 and O2, but your way would have them carry 6 cylinders

 

[LandonL]

I'm curious why RB's don't just carry three bottles, He, O2 and N, separately. I'm sure there must be a good reason or folks would be doing it.

No point really in adding a third tank to control the He percentage... A whole lot of complication for no additional advantage.

What would you think the advantage of this would be?

 

[kelemvor]

No point really in adding a third tank to control the He percentage...

A whole lot of complication for no additional advantage.

What would you think the advantage of this would be?

Just that it would be possible to get any mix you wanted without a particular fill.

Wookie, why 6? Are you counting bailout? I am not an RB diver so I'm not trying to argue, I'm just ignorant on the subject.

 

[Wookie]

Just that it would be possible to get any mix you wanted without a particular fill.

Wookie, why 6? Are you counting bailout? I am not an RB diver so I'm not trying to argue, I'm just ignorant on the subject.

Yes, bailout.

 

[LandonL]

Just that it would be possible to get any mix you wanted without a particular fill.

Hmmm, yes I guess, but remember in a CCR you are diving a fixed pO2, so the percentages shift as the oxygen percentage does anyway. Really you should get the proper fill to start out with.

I can imagine people would argue adding a third tank controlled by another solenoid (or not) would add further complication to the system, an additional point of failure, possible problems with Isobaric Counter Diffusion, problems with using an ADV, inability to use your dil tank with a BOV, the need for additional sensors for the He, etc.

I guess we are in the A&I thread though so we shouldn't derail the topic. Interesting topic actually though.

 

[Ayisha]

On a rebreather on the surface the counterlungs are a large fraction of your buoyancy. If you take the DSV out of your mouth without closing it or if you pass out you instantly lose about 7 litres of gas and lose buoyancy. A RB diver passing out on the surface is very vulnerable to this.

Drowning is almost certain.

Sotis passed out on the boat after the third deep dive with minimal surface intervals.

Could a chin strap have prevented that loss of buoyancy in case of unconsciousness? If so, why aren't chin straps widely used? Just wondering.

 

[LandonL]

Could a chin strap have prevented that loss of buoyancy in case of unconsciousness? If so, why aren't chin straps widely used? Just wondering.

The pressure from the breathing loop at the surface would push the air/gas out anyway, even if you had a chin strap. If you went unconscious you wouldn't be able to keep the seal around the mouthpiece to keep the gas inside the loop when your jaw relaxed.

 

[TotDoc]

Could a chin strap have prevented that loss of buoyancy in case of unconsciousness? If so, why aren't chin straps widely used? Just wondering.

Maybe - but only if an open loop falling from his mouth and flooding the unit was the cause of his plunge to the bottom - which I do think is a reasonable possibility. Then again, if he was diving a revo, don't those come with a gag strap now? I guess it's worth knowing if he already had one or not before we speculate on if it could/would help.