Exceeding NDL on an al80?

[mainedvr]

With your current SAC rate and staying within recreational depths can you have NDL become the limiting factor on your dive if you surface with 500psi in an al80 cylinder? Not a repetitive dive.

I can normally, including plenty of profiles run on the U.S. Navy tables.

I've heard it at least a dozen times that with 68cf of gas, there's no need to monitor NDL for the average diver if there are doing only one dive on a weekend.

Anyone that makes a statement like that would worry me to dive with, while it may be true monitoring is what IMHO a competent diver does nothing left to chance. But it is a good question.

 

[atdotde]

Thanks for setting me straight on this. I have my profiles stored in Subsurface. Is there a way to use those profiles to compute nitrogen exposure for air vs. EAN?

Sure. This is what the displayed ceilings and the heatmap are about. Change the gas for the dive in the equipment tab and those will update.

 

[clownfishsydney]

On every single dive I do (even on 32%) using an 80 or 100 cf tank I could easily end up in deco and still surface with 80 bar (over 1000 psi). Today I did a bottom time of 29 mins at an average of 26 metres (78 feet) and still came up with 100 bar or almost half a tank. I left the bottom with about 2 minutes to go before deco.

And to be honest, on most dives, I will go 20 to 30 minutes before I will even check my pressure gauge to see how much air I have left. Why? Because I can tell easily if my air use is even a little over my normal rate and of course I can hear if there is a leak. Most people I dive with operate on a similar basis.

 

[mi000ke]

Sure. This is what the displayed ceilings and the heatmap are about. Change the gas for the dive in the equipment tab and those will update.

Thanks!

 

[MXGratefulDiver]

I do both and have exceeded NDL many times... with full knowledge of it and sufficient reserve to complete required stops

Likewise, Dr. Bill ... but I normally dive tanks with sufficient gas to go into deco and honor the obligation.

... Bob (Grateful Diver)

 

[drbill]

Likewise, Dr. Bill ... but I normally dive tanks with sufficient gas to go into deco and honor the obligation.

... Bob (Grateful Diver)

Bob, isn't that what I said?

 

[boulderjohn]

Do you include contingency plans for a loss of gas through, say, a valve malfunction?

 

[MXGratefulDiver]

Bob, isn't that what I said?

... not in the reply I responded to ... perhaps earlier in the conversation ...

... Bob (Grateful Diver)

 

[MXGratefulDiver]

Do you include contingency plans for a loss of gas through, say, a valve malfunction?

In my case, yeah ... if I'm not diving with a buddy I'm packing an AL40 pony ... at deco depths it's good for about 30 minutes ...

... Bob (Grateful Diver)

 

[Jack Hammer]

I think most folks with a lot of dive experience, basically "comfortable in the water", can easily get into some level of mandatory deco at normal recreational depths with an al80. For resort, vacation, or most newer divers I think an al80 will keep them out of deco.