Reconsidering Deep Air?

[Akimbo]

And, it is old and outdated knowledge that your bubbles rise at 60 ft/s.

I should have been more specific. The smallest bubbles about the diameter of a pencil eraser are pretty close. My Scuba instructor was an obsessive mechanical engineer in real life. He actually measured it with a watch and downline. They told us the same thing in the Navy years later. I never bothered to measure it myself but my "time to the first stop" was always within seconds.

 

[Celt]

A saturation diving complex and a good crew. I locked out at just under 950'/290M nearly 50 years ago. We supported a team that locked out at 1,010'/308M about a month later. There have been thousands of man-hours in Sat at these depths without a loss of life.



I haven't seen HydrOx considered shallower than the 1,600'/500M range. I don't believe that Hydrox has been used since the Comex's demonstration lockouts at 2,300'/701M in 1992. Based on new sat systems being built, it looks like 400M is the consensus on where ROVs becomes more cost-effective than sat divers.

I meant what adjustment can the diver making the 800 foot dive in the video make.

 

[Degenerate]

Or turning the gas back a quarter turn. or mask-on-forehead means panic.

These two are major reasons I steer clear of boat dives with the local club, fiddle with my valves and we're gonna have an argument.

 

[Celt]

Because the 800ft dive is planned with the goal of minimizing risk wherever possible while still achieving the objective. The 187ft air dive isn't. You're conflating residual risk that can't be mitigated with unnecessary risk that is willingly accepted.

All dives are planned you just have to make a personal choice on how much risk you’re willing to accept.

 

[tursiops]

I should have been more specific. The smallest bubbles about the diameter of a pencil eraser are pretty close. My Scuba instructor was an obsessive mechanical engineer in real life. He actually measured it with a watch and downline. They told us the same thing in the Navy years later. I never bothered to measure it myself but my "time to the first stop" was always within seconds.

60 ft/min is 30 cm/s. According to this paper, that would require a bubble of about 2 cm diameter.

The graph only goes down to about 0.2 cm diameter, or 2mm, at abut 18 cm/s (35 ft/min). This agrees with some later work on small bubbles:

 

[100days-a-year]

As most US spearfishing is done in jurisdictions that preclude RBs, there will be a lot of diving done on air for years to come.

I would loved to have had an option to dive an RB commercially, He costs would have been astronomical and carrying enough for a 3 or 4 guys for 4 to 7 days would be impossible.

 

[rjack321]

All dives are planned you just have to make a personal choice on how much risk you’re willing to accept.

A commercial saturation dive in a heated habitat with associated medically managed decompression has nearly a 100% survival rate and a very low risk of adverse health effects in the short term. Over the last 100 years the commercial folks have already taken a long list of actions to reduce the risks to as near zero as can be achieved given the uncertainty in human physiology and the fact that sometimes equipment fails in unpredictable ways.

An 800ft recreational CCR or worse OC dive has a sky high mortality rate and extreme risk of death or injury. Risk reduction is basically non-existent and you might as well be a caisson worker in the 1880s. A 50% plus death and injury rate is just part of life back then.

But you knew that and just want to argue that deep air is a risk people should be free to take and ain't that bad.

 

[Celt]

A commercial saturation dive in a heated habitat with associated medically managed decompression has nearly a 100% survival rate and a very low risk of adverse health effects in the short term. Over the last 100 years the commercial folks have already taken a long list of actions to reduce the risks to as near zero as can be achieved given the uncertainty in human physiology and the fact that sometimes equipment fails in unpredictable ways.

An 800ft recreational CCR or worse OC dive has a sky high mortality rate and extreme risk of death or injury. Risk reduction is basically non-existent and you might as well be a caisson worker in the 1880s. A 50% plus death and injury rate is just part of life back then.

But you knew that and just want to argue that deep air is a risk people should be free to take and ain't that bad.

I think you’re mixing up my post with something else but what’s your point, my point is diving air to 187 feet is a minor risk for some people when compared to other risks they may have taken.

 

[Degenerate]

I think you’re mixing up my post with something else but what’s your point, my point is diving air to 187 feet is a minor risk for some people when compared to other risks they may have taken.

It might be a minor risk compared to other risks they have taken, but the risk is still much higher than it would be if the same dive was done with an appropriate gas mix with helium in it, there is a very easy way to reduce the risk and I don't see a reason to not take that precaution if possible.
I used to ride bikes around tracks with speeds upwards and sometimes extending 300km/h, the risks I took were great but I would never use them to justify doing risky dives by saying "oh this one thing I used to do was way more risky so this should be fine".
We know you dive deep air and advocate it as it is not a big deal but it absolutely can be, and will be, for the majority of divers.
If it works for you then that's fine, but telling others it's a good idea because you do it yourself without issues is pretty reckless IMO.

 

[100days-a-year]

Pretty obvious some people are critically impaired @.79 PPN , some @1.58 , some @2.37 , some @3.16 , some @ 3.45 or better .
My DW says arguing on the internet proves I'm a .79