No Deco Diving: When Do You Head Up?

[Crowley]

Those of us who are in the know and dive lots and lots may choose to ignore computer or table NDLs knowing we willingly accept the increased risk of a trip to the chamber. Yes, most computers and tables are super conservative and this is for a damn good reason.

When diving recreationally I generally start heading up when my computer shows 1 minute prior to it's NDL. When I brief my customers or students I ask them to let me know 3 mins prior to the computer's NDL.

It's a personal choice, but I dive almost every single day and am not willing to put my job at risk by continually pushing limits that over 100 years of decompression research has generated for very good reasons. I know people who've gotten bent for no apparent reason without even approaching an NDL or in fact doing anything at all that might predispose them to DCS. It happens, therefore I approach my own diving with the same conservatism.

Safe diving,

C.

 

[bamamedic]

Hmmm....

When I was a fairly new diver, I would usually always reach my turn pressure before I reached NDL. As I grew more comfortable in the water, and my SAC rate improved, I would usually start heading up within 5 min of my NDL.

But it didn't take me long to discover that when I did those dives to within a min or two of NDL, then immediately head to the surface with a 3 minute safety stop at 15 feet, I'd be so exhausted at the end of a dive day that I would barely be able to drive home, then I'd go fall asleep on the sofa for about 10 hours.

I started fooling around with decompression diving (usually just 10 min or so of deco at 20 feet on EAN50) and was surprised to discover that I felt tons better after one of those dives, even though I was was deeper and stayed longer than an NDL dive.

So, I realized through personal experience, that the NDL is a black line drawn through a very gray area...now, I kind-of-sort-of do my own thing as far as NDL dives. If I'm going to be diving a lot that day, I incoporate a deep stop and an extended safety stop on my dives, or I'll switch to O2 during the safety stop. I've learned to treat all NDL dives as decompression dives, in a way.

 

[ucfdiver]

I dive minimum deco every dive (similar concept to safety stops). If I go over the "setpoint" (ratio of depth/time that's basically NDL) on a recreational dive, I'll add 1 minute to minimum deco for every 1 minute I stay beyond the setpoint. Keeping on a schedule like this allows flexible dive planning, and the minimum deco allows for longer repetitive dive times.

And then if there's dives like Friday night where I wanted to see something that required us to go 90min over NDL. If that's the case, I'll bring deco gas and do what it takes to do the dive.

I don't like letting deco dictate my dives, so I always plan for some flexibility.

 

[pittyyofool]

NDL is for noobs! only because they do not know how to work beyond them. The NDL table is kinda seen as a holy grail to a standard recreational diver. That is a good thing, it keeps people safe, could you imagine a bunch of brand new divers trying to do deco stops before they understood the physics of what takes place in the body. On every dive past 50ft I plan on doing at least 1 deco stop, and I know the times depending on the estimated depth. Deco takes planing, and should only be done by those that have prepared in advance for it.

 

[LiteHedded]

I dive minimum deco every dive (similar concept to safety stops). If I go over the "setpoint" (ratio of depth/time that's basically NDL) on a recreational dive, I'll add 1 minute to minimum deco for every 1 minute I stay beyond the setpoint. Keeping on a schedule like this allows flexible dive planning, and the minimum deco allows for longer repetitive dive times.

And then if there's dives like Friday night where I wanted to see something that required us to go 90min over NDL. If that's the case, I'll bring deco gas and do what it takes to do the dive.

I don't like letting deco dictate my dives, so I always plan for some flexibility.

showoff!

 

[ucfdiver]

showoff!

Says the one who went to eagles nest Saturday.....you were over the NDL after what, like 3 minutes into your dive

I had bananas and Gatorade waiting for me at deco. I think you're jealous.

 

[LiteHedded]

Says the one who went to eagles nest Saturday.....you were over the NDL after what, like 3 minutes into your dive

I had bananas and Gatorade waiting for me at deco. I think you're jealous.

not sure
what's the mdl at 238'?

 

[ucfdiver]

not sure
what's the mdl at 238'?

Not sure. I don't have AOW or my PADI deep specialty yet :depressed:

 

[pittyyofool]

According to my USN "air" diving tables the NDL for 240fsw is somewhere less than 5 min. At 5 min there is a 2 minute "air" deco at 10FSW.
PS. UCFDiver, good luck finding that type of depth on a padi table, and cliff bars are tasty underwater.

 

[LiteHedded]

According to my USN "air" diving tables the NDL for 240fsw is somewhere less than 5 min. At 5 min there is a 2 minute "air" deco at 10FSW.
PS. UCFDiver, good luck finding that type of depth on a padi table, and cliff bars are tasty underwater.

that wouldn't work for my mix