Padi Dive Wheel ?

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Watergame

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I want to know if the Padi dive wheel from the early '80's is still the same wheel/chart as the new ones. I had a dive master tell me they were re-called by Padi he thought. I'm not so sure. Have the dive tables changed much in the last 20 years? Thanks
 
Watergame once bubbled...
I want to know if the Padi dive wheel from the early '80's is still the same wheel/chart as the new ones. I had a dive master tell me they were re-called by Padi he thought. I'm not so sure. Have the dive tables changed much in the last 20 years? Thanks
PADI released a new RDP in the late '80s, so the wheel would also have been updated to reflect that.

As far as dive tables changing... PUBLISHED tables haven't changed much, but theories have been updated and tested and do show various changes... addition of deep stops, etc...
 
. . .and there are a LOT more groups. I still have my old table and the repetitive groups run from A to N, and on the new table they run all the way to Z-- an increase of from 14 to 26 groups, so there's a lot more fineness to the new table. Old non-decomp limit at 60' was 60 minutes, now it's 55, to give you an idea of how much more conservative they are. The old table doesn't have recommended safety stops, there are lots of them on the new table.

My old table is copyright 1983 and the new one is brand new, but it has multiple copyright dates on it, so I don't know when the changes were made.

Anyway, I can't find my wheel, but I'd check to see if you have the latest. Some folks might say the old tables worked fine and keep using them, but I'm more of the "better safe than sorry" school, and I'll use the most conservative thing out there.

JPC
 
When I certified in the early 80's we used the old navy based PADI tables and the Wheel was just being developed. (It previewed at trade shows in 1984 or 85 I think) As I remember the Wheel was marketed on the premis of being much more conservative than US Navy/PADI tables but more than made up for this extra conservatisim and allowed increased bottom time by giving you credit for shallow parts of the dive rather than requiring you to asssume a square profile at max depth.

The "new" PADI RDP had the same NDL limits as those used for non multilevel dives on the Wheel. (the multi-level NDL's on the Wheel are slightly less) So, I doubt there are two versions of the Wheel floating around as the new doppler limits used in the new RDP were incorporated in the Wheel from the start, but you could check with PADI to be sure.
 
I've been wondering for ages why the PADI dive tables are not openly found on the net for people to refer to, and print out. Would it not be a way of promoting safe diving?

If the answer is because it is to "SELL" the tables, that is an extremely bad answer. I reckon they should be readily available, and those who are serious about getting a proper one, pay for it.

After all, how hard is it for someone to borrow one, and scan it if they really wanted to?

My vote is safety over the dollar$.
 
JohnCollins once bubbled...
. . .and there are a LOT more groups. I still have my old table and the repetitive groups run from A to N, and on the new table they run all the way to Z-- an increase of from 14 to 26 groups, so there's a lot more fineness to the new table.

The US Navy tables that the PADI table was modeled after had groups A-Z but they just weren't groups you would get into in non deco diving, so they just don't show on the PADI table for the sake of brevity.

The "new" PADI table uses a 6 hour out and the underlying assumption that you completly off gas in 6 hours - a very dubious assumption. The Navy/old PADI table assumed a 12 hour out, so in effect you have more "fineness" in the new PADI tables and groups but only because the table is operating in a much more restricted range in terms of offgassing. The last thing I would call it is safer particlarly on multiple dives over multiple days. The "new" RDP is also one of the most liberal of the current crop of dive tables around.
 
The "new" RDP is also one of the most liberal of the current crop of dive tables around.
I don't agree. Compared with a lot of tables the ("new") RDP is clearly more conservative (e.g. MN90, BSAC 88, US Navy, Bühlmann ZH16). Also, the RDP is generally considered a conservative table all-around. The fact that there are some even more conservative tables/deco programs around is incidental. This is BTW an excellent topic for the Dr Deco section of this board, for many reasons ... :wink:
 
DA Aquamaster once bubbled...
The "new" PADI table uses a 6 hour out and the underlying assumption that you completly off gas in 6 hours - a very dubious assumption. The Navy/old PADI table assumed a 12 hour out, so in effect you have more "fineness" in the new PADI tables and groups but only because the table is operating in a much more restricted range in terms of offgassing. The last thing I would call it is safer particlarly on multiple dives over multiple days. The "new" RDP is also one of the most liberal of the current crop of dive tables around.
The apparent "liberalness" of the PADI RDP is because it recognizes that the 60 minute halftime compartment is the slowest controlling compartment in normal recreational diving.

The PADI RDP tracks only the 60 minute compartment. 6 hour SI will reduce that compartment to only 1.6% loading above normal sea level loading. For all reasonable people, that is fully offgassed. This is particularly true since you will only reach Y or Z pressure groups (92% or 95% of DSAT 60 minute M value I believe, where 24.8fsw absolute is 0%) by shallow dives that exceed 120 minutes in length.

All dives deeper than 40' hit NDL based on faster compartments, but then the N2 decay during SI is calculated using a 60 minute HT, resulting in extra conservatism.

I have not reverse engineered the Navy tables since they don't seem to be consistent. They do however seem to be primarily based on the 120 minute compartment, which is not the limiting compartment for normal rec diving.

Slower compartments only become the limiting compartments for very, very long shallow dives. Those dives are controlled on the PADI RDP by the fine print on the back, with restrictions on repetitive dives if you enter W, X, Y, or Z pressure groups. Those restrictions keep your average depth (including SI) no more than 23' and thereby keep from loading up the slowest compartments beyond limits.

The M values upon what the DSAT/PADI table are based are more conservative than the Navy (Workman 1965) in each and every compartment. The DSAT values are similar to the ZHL16 values -- a little more liberal for 5 or 10 minutes (5, 8, 12.5 for ZHL16) compartments; more conservative for most.
 
bakpakka once bubbled...
I've been wondering for ages why the PADI dive tables are not openly found on the net for people to refer to, and print out. Would it not be a way of promoting safe diving?

If the answer is because it is to "SELL" the tables, that is an extremely bad answer. I reckon they should be readily available, and those who are serious about getting a proper one, pay for it.

After all, how hard is it for someone to borrow one, and scan it if they really wanted to?

My vote is safety over the dollar$.

So, you develop a product that saves lives, lets just call it a widget. It works really well and is very popular. When this happens you are forced to give it away for free, and on top of that, any research and development you do on the product is to be provided free of charge, regardless of the costs. Would you happily agree with this, or would you tell the people who spout that tired old leftist moniker of “blah blah blah before money” or worst yet, “before PROFITS” (Ohhh profits what an evil concept) Would you tell them to get stuffed!

I think you would probably tell them to get stuffed, and so you should!
 
Guess we've paid for our PADI accreditation, gotta fork out more for safety I guess. I reckon an RDP is such an important "widget" that it should be made available to all who have already paid their dues in order to become a diver.

It's rather like patenting the cure to AIDS. All mankind should donate to the development of such a cure. But hey, of course a company with financial focus should take it up, patent it and charge exorbitant fees, shouldn't they. Now, that's rather self-centred, eh?

Well of course my two cents about the RDP ain't gonna make it available for free, but copyrighting it? Perhaps selling the genuine stuff is fine, but prohibiting others to copy it for safety / life saving?
 

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