Regular NON-WHEEL Dive Tables for Multi-Level Dives???

[noshow]

I have a question for everyone...

Has/does anyone use the PADI (or any other agency for that matter) for non-square mutilevel dives?

For example, I did a dive that as a square profile exceeds the PADI dive table no deco limits.

eg) 70 feet for 20 minutes... 40 feet for 25minutes... max depth: 70 feet; total dive time: 45minutes.

1. When done as a square profile on the PADI tables it exceeds the no deco limit.

2. when done with the same tables with a ZERO (o) surface interval between the 70 feet and the 40 feet, one ends up in the "P" pressure group. This can then be used to plan the next dive.

I realize that the two simple answers will be a) go use the wheel and then b) go purchase a computer. However, intiuitively this seems to work. Although it is probably still not as generous as the wheel and certainly not the computer, it still does not blow the square profiles of the tables. I use a simple bottom timer.

Any comments???? Any experience???????

 

[devilfish]

If you didn't surface between the two profiles what you basically did is a multilevel dive. That is all a computer or the wheel does with much finer increments.
Before the computers we used to do what we called "step ladder" dives. Refigured on a flat table time allowed at shallower depths resulting what is called nowadays multilevel dives.

 

[Uncle Pug]

Originally posted by noshow
Any comments???? Any experience???????

Do yourself and your family a favor...
Get GUE training before you start trying to do this stuff.

 

[noshow]

I'm working on it... hopefully in July!

 

[Zept]

Originally posted by noshow
For example, I did a dive that as a square profile exceeds the PADI dive table no deco limits.

eg) 70 feet for 20 minutes... 40 feet for 25minutes... max depth: 70 feet; total dive time: 45minutes.

Um... if you don't have a wheel and you don't have a computer, how did you plan this dive? How did you decide whether it would be safe?

Zept

 

[noshow]

I did the dive with 2 buddies who were both using computers and we had planned the dive beforehand...

 

[Uncle Pug]

Originally posted by noshow
I'm working on it... hopefully in July!

Super... where?

 

[noshow]

A dive shop in North Van is working on getting a GUE instructor up from Seattle , FifthD I think. They've been chatting.

I am crossing my fingers that it goes through. I already have my name on the list. I think I'm first...

 

[Piscean]

I asked my instructor this when I first learnt to dive and he told me you can't use the table to do this. I could never understand why not. I mean, if the tables say 0 to 5 min surface interval then they had better work for 0 min surface interval. So anyway, now I am doing the PADI Divemaster course and if you restrict yourself to 10 foot intervals (wheel can do five also) and then calculate everything on the tables and the wheel you get the same answers. The only thing is that on the tables, you don't have the multilevel dive limits which stop you doing dives which are not safe. For example, after a 100 foot dive, the next segment must be 70 or above. Also you can't go to the NDL on the tables, but have to reduce your time slightly. So in short, the tables do give the right answers mostly, but they are not safe because of the additional limit information which you do not have. If you want to do this, then buy a wheel or a computer. To be honest, I don't understand anyone who likes diving not having a computer or using the tables or wheel properly - if you are unlucky you could end your diving career for ever and then I am sure you will regret the $50 you saved on the wheel or the $250 you saved on a computer. But that is just my opinion, it is your life not mine. What is GUE? I assume this is actually some sort of profile planning software, so my preaching is in vain, but I don't mean to preach anyway, I'd just feel sorry for anyone who got bent to save $50.

Piscean

 

[JamesK]

The problem I see with this is the ascent. Even with a 30second surface interval, the tables take into account your ascent, your safety stop, and the amount of off-gassing you will do on both of these. If you do not take the additional 40-0 foot ascent, then you miss all of the off gassing you will effectively do for that dive, that your tables take into consideration when calculating your new pressure group.