Depth averaging tables.

[DA Aquamaster]

Yes, you can do this on any set of tables. But you do not get an answer that you should use, unless you are very far away from any limits. That is why the Wheel was invented.

This paper explains how to validly use the RDP with multilevel dives. The same ideas will apply to all tables, but there is no way to test them because there is no equivalent to the Wheel for those other tables. Sorry, I cannot attach the paper (too large), but you can get it on Rubicon with this link.

The PADI Wheel uses shorter no decompression limits for multi-level dives, which is the major difference between the Wheel and the PADI RDP.

However, after we started diving with the Wheel in the late 1980s some of us who liked to play with tables figured out that if you apply the same NDLs and rules to the table, you got the same results.

The caution is that you also have to follow the same set of rules as you would for the Wheel, in terms of only one segment deeper than 80 ft with subsequent segments at least 20 ft shallower, mandatory safety stops (which in effect then are decompression stops) and specific surface intervals for repetitive multi-level dives.

If you look at the unintentional deco segments of the table, you'll notice that a 3 minute or 5 minute decompression stops cover a fair degree of sins in terms of exceeding the NDL's, and in that regard those safety stops are essential to doing multi-level dives safely with the wheel, and it was something we regarded as essential when doing multi-level dives on the RDP as well.

Now, to be fair, we were also divers who learned on the old PADI table which used the old US Navy limits before the newer PADI RDP came along with shorter NDLs, so we were a little less leery about pushing the limits of the more conservative RDP - along with being young, inexperienced and perhaps less prudent than we should have been, so take it all with a grain of salt.

 

[tursiops]

along with being young, inexperienced and perhaps less prudent than we should have been, so take it all with a grain of salt.

LOL! I have no idea what you are talking about.

 

[rhwestfall]

We played a bunch with things in the late 80's (wheel included), but in this day and age, for possibly <$175 I can get some form of a PDC to run multi-level calculations (and I utilize a whole bunch more) for me, so why bother??????????????? Sometime, you have to stop trying to be a "caveman", and take advantage of things....

As they say: If someone hadn't re-invented the wheel, we would all still be traveling around on stone wheels.....

 

[BRT]

We played a bunch with things in the late 80's (wheel included), but in this day and age, for possibly <$175 I can get some form of a PDC to run multi-level calculations (and I utilize a whole bunch more) for me, so why bother??????????????? Sometime, you have to stop trying to be a "caveman", and take advantage of things....

As they say: If someone hadn't re-invented the wheel, we would all still be traveling around on stone wheels.....

Spend $350 and carry 2

 

[DiveNav]

.......Which Pressure Groups did you use, RDP? USN? Other?

RDP.
If there is a strong request we can add other tables too.

 

[halocline]

Personally I kind of like the wheel. It's a perfectly acceptable back up for the type of recreational diving I do. I like the fact that it never runs out of battery power, I can step on it, drop a tank on it, whatever, and it still works. Well, sort of works.....

 

[Searcaigh]

I remember learning the wheel for DM class. As far as I was concerned it was pretty much useless and I knew I would never use it so I can't remember too much about it. I learned enough at the time to pass the exam but that's about it. I don't know if they even require learning the wheel anymore for DM, since I was in it back in 2001-'02
As I remember you could plan three separate depths but then you had to know in advanced the site you were diving so you could plan a wheel dive to calculate how long at what depth. But thet if you were diving an unknown spot for the first time and had no idea what depths you going to be at?
It was also fairly difficult to use as I remember, one digit off and the whole thing was thrown off.

Utter tosh!

The PADI wheel is not difficult to learn and use, and as for diving unknown dive sites, how do you plan these dives anyway?

 

[halocline]

The PADI wheel is not difficult to learn and use, and as for diving unknown dive sites, how do you plan these dives anyway?

Maybe you ask someone who's more familiar with the site before hand, maybe not, but for sure you plan a depth/time schedule and stick with it. If you miss some features of the site because they're too deep for your plan, oh well.

Or, you recalculate your plan mid dive, but to me that's fairly advanced if you're actually trying to re-plan with the wheel. Most recreational divers simply let their computer do the 'thinking'.

 

[Eric Sedletzky]

Utter tosh!

The PADI wheel is not difficult to learn and use, and as for diving unknown dive sites, how do you plan these dives anyway?

Screw the wheel! This isn't 1978 (or whenever it was created - who cares)

We dive many sites that are off the charts, have probably never been dived, and we have absolutely no idea of the terrain. In Northern California (North Coast) there is a lot of dramatic structure with deep canyons, walls, drop offs, shelves, pinnacles, etc. with pinnacles breaking the surface and sheer drop offs right besides those pinnacles dropping to 120 to 150 feet. There are deep cracks, crevices, swim throughs, corridors, boulders the size of school busses piled on each other that can create a maze of little tunnelettes. It's the most dramatic structure I've even dived, and according to many people I've taken there with a lot more world wide experience than me say the same thing.
When we drop anchor we have no clue other than what the sonar might have told us as we were cruising the site or the spot we dropped anchor.
It's happened that as we were anchored gearing up the sonar would flash between 124 feet and 25 feet. We figured it was on the blink since we were close to shore (cliffs) and we figured there was no way we were in 124 feet of water. Then when we splashed we found out we were anchored right on the edge of a wall and the readings were caused by the boat swing back and forth.
With the wheel I'd have to find places to go to obey the pre designated plan, but in a situation like I described it's just not practical or in some cases impossible to do that without finding yourself out in the middle of the water column or diving right under the boat if you found the exact terrain to make your plan work, but then you wouldn't be getting the freedom to explore anything.
Computers give us the complete freedom to explore and take everything in (in multitude of depths) that we might encounter around every corner. Computers opened up this type of diving and made it safe.

 

[rhwestfall]

comparing post #1 to post #29, both from you...... You talk in circles......