max depth with an 80 cuft. tank

[UCFKnightDiver]

Bent is (usually) fixable. Dead (usually) aint.

Personally I'd rather be neither... *shrugs*

 

[Superlyte27]

Unless you subscribe to the "drown and resuscitate" school of air sharing

LOL, too funny. I actually made the front page of the local newspaper one day for implementing that very practice.

I rescued a guy who didn't want rescued. He tried to down himself. I brought him to the surface. He punched me in the face and dragged me down with him. I waited until he was unconscious and brought him to the surface again where EMT's could resuscitate.

 

[MXGratefulDiver]

By the time I started diving below 100ft my SAC was already down to much better levels than are being quoted on this thread.

... that makes you much smarter than a lot of the folks I've seen at that depth around here ... including myself when I was a new diver.

Back then I could drain an AL80 in less than 20 minutes and never get below 60 fsw ...

... Bob (Grateful Diver)

 

[dktexas54]

Reread his post. He's talking about 105 for EACH diver not for the pair:
"assumptions: are heart rate is up, our consumption is up. Worst case lets say our total consumption for both divers now is triple or 105 psi sac rate x 2= 210 psi sac rate."

miketsp,
My hypothetical i admit for air consumption is probably too high. Please realize these are not my sac rates but I trying to project for very new divers, with little training, going places due to peer pressure etc and getting into a worst case situation. Intent of this thread is accomplishing my goal of getting people like yourself who are experienced to share their knowledge so others will learn. You cannot tell me unequivally that even a 210 psi sac rate at 120' might not happen. I really don't know. The point of my thread again is too make the less experienced divers reading this board ask questions. Cheers pal.

 

[MXGratefulDiver]

miketsp,
My hypothetical i admit for air consumption is probably too high. Please realize these are not my sac rates but I trying to project for very new divers, with little training, going places due to peer pressure etc and getting into a worst case situation. Intent of this thread is accomplishing my goal of getting people like yourself who are experienced to share their knowledge so others will learn. You cannot tell me unequivally that even a 210 psi sac rate at 120' might not happen. I really don't know. The point of my thread again is too make the less experienced divers reading this board ask questions. Cheers pal.

FWIW - I have measured some of my former AOW students with a "working" surface consumption rate as high as 2.8 CFM. It's not normal ... but it happens ...

... Bob (Grateful Diver)

 

[boulderjohn]

The calculations of rock bottom applied earlier are correct, but a lot of people have a different attitude about that in terms of OW diving in AL 80s. Here is the thinking:

1. I am doing NDL diving. Neither a safety stop nor the minimum deco concept are requirements for this but are instead additional safety measures. In the case of an emergency, I should be able to do a direct ascent to the surface at a safe speed and be OK without doing those stops.

2. The recommended 30 FPM ascent rate has been shown by recent research to be the sagest, but a 60 FPM ascent rate is still advocated by at least one agency, and that agencies extensive published research indicates that a diver within NDLs should be able to ascend directly to the surface at a 60 FPM rate safely.

Taking that thinking to its extreme, the logical consequence is that a diver needs only enough air to get to the surface with a buddy at a steady ascent rate of 60 FPM. That's not a lot of gas.

The complete rock bottom calculations done earlier are at the other extreme of safety.

I think most people are somewhere in between. When I am planning decompression dives where I know I must do those stops, you can bet I will do the rock bottom calculations described above. In a sunny reef dive within NDLs, I have to admit that I am a little more relaxed on those calculations. This is especially true when doing a real multilevel dive, where you might spend two minutes at 100 feet to check out the garden eels, ascend to 60 feet for a while, and then spend the remainder of the dive near the top of the reef.

 

[gcbryan]

Rock bottom does change with depth so two minutes at 100 fsw and then 60 fsw for a while would free up a lot of rock bottom reserves.