AVG depth on the fly?

[GrandpaScuba]

But that would only give me my air consumption, and not that of my divers. Or should every one of my divers be outfitted with an air-integrated computer too?

I don't follow how you plan on calculating the air consumption of a "group" of divers. At best you could come up with an average which doesn't help those consuming faster than the average. I think you're over thinking the problem. What you need to do is identify the diver who is sucking down the air the fastest and keep an eye on their consumption.

 

[oszillodrom]

If I have been diving with a group, I know that the diver with the largest consumption of air will be able to do a dive with an average depth of say, 12m for 60 min. That's the average depth I shoot for for the next dive, of course monitoring actual air consumption during the dive and adjusting accordingly. Usually that guess turns out to be pretty accurate. Average depth is a handy tool, as it directly relates to air consumption given a certain SAC/RMV.

 

[TSandM]

Any new divers reading this should be aware that tables are based on MAXIMUM depth, and using average depth with the RDP or other recreational dive tables (with very specific exceptions) is violating the model and therefore cannot be predicted to be safe. The models were not validated using average depth. There are those of us using a strategy involving average depth to manage our decompression status, but we are using other tables and accepting a lack of documented validation to do so.

bradells, as I said, I kind of build a profile in my head. My average recreational dive is about 60 minutes long. Shore dives involve starting in very shallow water, swimming deep, and returning, and are often rather check-marked in shape. I have a sense for how much time I spent in the deep segment of the dive, as a proportion of that 60 minutes -- it's usually about a third. The other two-thirds are spent in the shallow phase, because of the tail of the check mark. If I build the picture in my head, I can draw a line across it that looks like the average depth, and I have been surprised at how well that works. It fails if the profile is egregiously sawtoothed, but I almost never do that except in caves, and to be honest, I often let the computer tell me the average in a cave with a lot of ups and downs.

 

[MXGratefulDiver]

Any air-integrated computer will give you "Air Time Remaining". As a DM you should have pro-level equipment. Including an air integrated diving computer.

I guess my definition of pro-level equipment is a bit different than yours. Done over 3000 dives in Puget Sound, been teaching scuba here for almost 11 years. Never once found a reason to need an air integrated computer.

FWIW - I own two dive computers ... a Shearwater Petrel and a Liquivision X1. Neither is AI. Both give me everything I would ever want or need in a dive computer ...

... Bob (Grateful Diver)

 

[Mr Carcharodon]

Here's a write up more or less directly answering the original question: http://dir-diver.com/en/knowledge/average_depth.html

On reason to use average depth is to get everyone on a dive on one decompression plan. That is useful if there are different computers that give significantly different results. If you think it is heretical to ignore what your computer is telling you consider that most of the computer algorithms have no documented validation. Using the RDP with average depth is getting just part of the plan so you need to be careful. Still it can be instructive to look at the sum of average depth and NDL time and see if there are just a few numbers to remember.

 

[Diver0001]

Any air-integrated computer will give you "Air Time Remaining". As a DM you should have pro-level equipment. Including an air integrated diving computer.

I've been diving for 30 years. Made thousands of dives, a great many of which were "technical" in nature. I've tried AI computers in the past and I have no particular objection to them. However, I would object to characterizing them as "professional level" equipment. Some shops may want to spin this story to sell expensive gear to upcoming pros but frankly it's pure and unadulterated bull ****.

R..

 

[Remy B.]

No, it shows the average depth during the dive (Mares Puck Pro).

Ediit: I looked it up, the Puck Pro does, the Puck does not.

Correct the Punk Pro does, that is the one I have, the other advantage over the regular Punk is that in the Punk Pro you can set Nitrox, it is good no so expensive DC

 

[Bagster]

Any new divers reading this should be aware that tables are based on MAXIMUM depth, and using average depth with the RDP or other recreational dive tables (with very specific exceptions) is violating the model and therefore cannot be predicted to be safe. The models were not validated using average depth. There are those of us using a strategy involving average depth to manage our decompression status, but we are using other tables and accepting a lack of documented validation to do so...

Right, this is what I meant by my initial query. Thank you for clarifying.

 

[Edward3c]

Anyone have any links/anecdotes about how to go about figuring out your average depth on a dive on the fly?

BRad

Why. Plan the dive and dive the plan.

To many people just jump in and rely on their computer.

Last dive I did was planned to 30m for an hour in water: 15 min @ 25-30m, 20 min @ 15-20m the remainder above 10m. Went in with 230bar out with 110, single 12. Unfortunately we only did 54 min as my buddy was on 50bar, with a 15Lt cylinder.

 

[Diver0001]

To many people just jump in and rely on their computer.

It would seem illogical to me to ignore the information a computer provides you.

I hear a lot of people complaining about "riding" the computer and you even cited one of your own dives as an example of what not to do.... but frankly, incorporating the information a computer gives you and adjusting your dive on the fly based upon that information seems perfectly reasonable provided you are aware of what you are doing and why.

What's the difference between working out avg depth in your head every few minutes and incorporating that information on the fly into your dive plan (what at least one major technical agency teaches) and reading the average depth off of a computer screen and incorporating that information on the fly into your dive plan?

R..