Blindly trust computers?

[yle]

You are exceeding the NDL on the deeper level, before you go to the shallow level.

Yes. That's my point. First option does not exceed NDL, second option does. But both have the same total time and average depth.

 

[MaxBottomtime]

Depends what you're looking for.

I will admit that there are people who have incurred a deco obligation, satisfied it, and survived. In fact, I'm sure it's happened more than a few times.

But the original suggestion of using average depth was that planning a no-deco dive comes out the same. It's not.

There are a lot of divers that have not had deco training. The fact is that while all deco and no-deco dives go just fine when everything goes according to plan, we train for those rare times when something goes sideways.

If you're going to suggest that a diver that has had only OW training should be encouraged to plan dives that incur a deco obligation as long as their plan includes enough time at a shallow depth to clear that obligation... I'm going to respectfully disagree.

And yet your examples show a violation of the ndl each time. What others are trying to explain is that by averaging your depth during a dive, you will surface within a minute or two of what a computer is telling you. It's not rocket surgery.

 

[runsongas]

I see a lot of Suuntos on boats in Caribbean. In a group of 8 there'd typically be two of us with Leos and maybe another couple with not-Suuntos. On this board everybody dives in a shearwater backplate while bashing the scary conservative suunto watches... so of course they have all the sensor failures, too.

I think it's more accurate to say that nobody's sued mares/oceanic over something that sounds borderline frivolous.

even by your example, suunto has maybe half the market. but you don't see mares/oceanic/cressi owners having nearly the same frequency of depth sensor issues and those three brands combined are probably as numerous as suunto.

 

[BRT]

And yet your examples show a violation of the ndl each time. What others are trying to explain is that by averaging your depth during a dive, you will surface within a minute or two of what a computer is telling you. It's not rocket surgery.

Please give me a mental average of 3 minutes at 40', 4 minutes at 60', 4 minutes at 110', 6 minutes at 100', 12 minutes at 80', 3 minutes at 90', 5 minutes at 60', 3 minutes at 50', 3 minutes at 60', 5 minutes at 40' and 8 minutes at 30'. That is not nearly as complicated as we usually dive so I'm sure you can do that in your head as you look at the fish.

 

[PfcAJ]

Please give me a mental average of 3 minutes at 40', 4 minutes at 60', 4 minutes at 110', 6 minutes at 100', 12 minutes at 80', 3 minutes at 90', 5 minutes at 60', 3 minutes at 50', 3 minutes at 60', 5 minutes at 40' and 8 minutes at 30'. That is not nearly as complicated as we usually dive so I'm sure you can do that in your head as you look at the fish.

70’ ish.

 

[BRT]

70’ ish.

So I have exceeded NDL's?

 

[lowviz]

So I have exceeded NDL's?

Whose NDL? Do you have any feeling for how various algorithms vary?

Your profile is child's play. Guesstimating 15 at 100, 20 at 80, and around 6 at 50. The other depths are too shallow to matter.

In other words, 70'ish if you aren't breathing air.

 

[PfcAJ]

So I have exceeded NDL's?

I’d wager that a computer wouldn’t give you a mandatory stop on that dive.

 

[BRT]

Whose NDL? Do you have any feeling for how various algorithms vary?

Your profile is child's play. Guesstimating 15 at 100, 20 at 80, and around 6 at 50. The other depths are too shallow to matter.

In other words, 70'ish if you aren't breathing air.

Is it 70'ish if I am breathing air? I calculate it a 66' average. So 70 it is. 70' for 56 minutes. On air or anything else you want to breathe. On air it is a deco dive, unless you are diving a computer. On my computer it won't even nudge limits.

 

[lowviz]

So 70 it is. 70' for 56 minutes.

So you are crediting all the shallow times as 70'? How long can one stay at 30' before incurring an obligation?

I'd say the time at 70 (used to calculate your NDL) is more like 40-45 min. See above. That is a guesstimate. If my PDC differs by any substantial amount from that approximation then we have a problem somewhere.