No Deco Diving: When Do You Head Up?

[don Francisco]

The question is poorly phrased.

There is a turn time, wherein one would be turning the dive and returning to a starting point, ie. an anchor line. And there is an end of dive time, wherein one would be beginning an ascent and/or ending the dive. Obviously in managing dives there would be a material difference between the planned turn and end times.

Also for those who, like myself, do mostly drift and/or multilevel diving on walls, the NDL considerations are very different than for those doing square profile wreck dives off moorings.

If you mean to find out how close to the NDL we're willing to dive, then you should ask that directly.

 

[DandyDon]

The question is poorly phrased.

If you mean to find out how close to the NDL we're willing to dive, then you should ask that directly.

I still don't understand the question as compared to the choices.

Does he want to know how close or how far beyond dive computer ndl one will go? If so, how does one answer.

Maybe he would like to PM a Mod to close the thread and try again...?

 

[Shcubasteve]

...Maybe he would like to PM a Mod to close the thread and try again...?

Poorly phrased it right! Sorry all... I will try again

How about:

How close to your NDL are you willing to get?

 

[DandyDon]

...close the thread and try again.

 

[eponym]

Thank you to all who responded.

Imagine my surprise after voting . . . No, I won't spoil it.

The thread was titled: No Deco Diving.

And as you probably inferred from Dave's first reply, in a literal sense there's no such thing. If you want to please everybody (well, it's good to have a dream), ask about "Recreational" or "No-Stop" diving.

How about: How close to your NDL are you willing to get?

Not bad. But if you want to limit it to computer users (as your opening post seemed to do), add that information to the question. And add choices such as "one minute over" or "five minutes over." I'm not sure it will change the outcome of the poll, though.

As someone not trained (no desire) in advanced EANx/deco procedures, I treat my NDL as a line never to be crossed. I know I'm not prepared for deco and will stay within NDL at all times.

I applaud that.

-Bryan

 

[String]

NDL is not some magic dividing line which magically separates different types of diving. If anything its dangerous thinking there is an artificial delimeter

 

[Reg Braithwaite]

Ok, I think I understand. One question is this:

Given some method for computing an NDL that you trust, meaning you believe that if you cross exceed that value you must do deco before returning to the surface, how close to that value are you prepared to go during a dive?

The further explain, if you believe your computer is 10% conservative, the when it shows you 20 minutes NDL for a dive, you believe you have approximately 22 minutes before going into deco no matter what the computer says.

In this case, the question is about your tolerance for risk and not your belief in the conservatism of your tools. And I answer, I theoretically dive right to the NDL because I believe I have the equipment and protocol for safely handling a small amount of deco should I exceed the NDL.

That's theory. In practice, since I switched to a conservative protocol for gas planning, I am now almost always limited by gas rather than by NDL because of the types of dives I do.

 

[Diver0001]

Regardless of microbubble level or computer type, how close to your NDL do you allow your computer to get? I'm comfortable with my decision based on conditions and am curious what others practice. Thanks in advance for voting.

There are a lot of factors involved here but let's assume:

1) you're swimming an "out and back" navigation pattern over the same dive area
2) you have enough air for the whole dive
3) there is no significant current or any reason to believe that the trip back will take longer than the trip out.

In that case you can compare two numbers:

- the NDL
- your bottom time.

If you turn the dive just when those two numbers are the same then you'll be able to finish the dive without exceeding the NDL.

*in this particular scenario!* -- which is arguably the simplest scenario for planning. Note: there are many many scenarios in which is simple logic breaks down.

R..

 

[gcbryan]

The real question seems to be how conservative are you with regards to your NDL? Your actions really depend on the dive profile. If it's a square profile then you might decide to start to go up when you are still 5 minutes from the NDL at that depth.

If you are doing a multi-level dive you might start getting shallower when you are 1 minutes from the NDL and this could still be regarded as conservative if you move on up to a much shallower depth (30 fsw or so) and stay there for a while before your slow ascent directly to the surface.

This question (how conservative are you regarding the NDL's) doesn't really make for a meaningful poll question.

 

[Blackwood]

A combination of what wedivebc and John_B said:

It depends on how much gas I have.