Tables and Diving time

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M

Manogr

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Hello all...

I know that this question will appeal as really newbie one but...:)

Let's assume that we are using only tables as used in the Padi OW..no computers...no wheels...

We read the NDL for a particular dive and we see that it is for example 10 minutes (no tables with me...hypothetical). We start our dive...and go to the particular depth in 8 minutes (there are many things to see on your way down :) we stay there for 10 minutes and then start moving up, we spend another 20 minutes in various other depths above the maximum one...then do 3 min safety stop and go up... the total diving time is 41 minutes...Here is the question... can we be sure that we are safe ? what we knew from our tables was about 10 minutes NDL..what about the rest of the time that maybe were in realy deep waters but above the max ?
I know that computers dont have problems like that but I really want to know the philosophy of the tables and how old divers (before comps) dit it..

Thanks you all...

Manogr
 
Well I can give you a textbook answer, which is NO. You are not safe per the tables. You would have exceeded your NDL by 11mins and you now must make stops as noted by the tables. (I am not looking at a table either) It was my understanding that with tables you must all ways do your equations with the max dept and time. I think the 10 mins includes your bottom time and accent. I wouldn't do that with out a computer.

As for the other questions, I have only 12 dives right now so I am still what you call a newbie. Please correct me if I am wrong.


 
OK -- assuming you are diving strictly by tables....

The total time spent descending and on the bottom before beginning ascent is known as your TOTAL BOTTOM TIME.

The dive tables and no-decompression limit times for various depths that you learn about in BOW classes are to be followed using TOTAL BOTTOM TIME. So, if your NDL for a particular depth is 10 minutes, you should include the time descending and at the max depth in figuring out how close you are to NDLs.

Obviously, this would be very conservative, since in your scenario, you spent a significant amount of time descending to your max depth...but if using tables in the strictest sense without adjusting for the descent time spent at shallower depths, this is how you should think about it.

Kudos to Stephen -- I forgot to mention the part about direct ascent/safety stop (30 feet per minute, of course)

 
thank you all for your answers.... I knew what you already said (i was a good student in my OW class :) ...

I am asking more in an academic way but let me use an example with tables in front of me...

Lets say I am starting a decent and arrive in 35 meters max depth...the NDL is 14 minutes. Lets say that I decent in 2 minutes and spend 10 minutes there at the bottom so I start my accent...my total bottom time was 12 minutes...instead of going straight to the surface I spend 15 more minutes in, lets say, 20 meters or less...As a result I am going up in 29 minutes...I will have a problem ???

The point of my question is that I found this amazingly conservative...just stay in the water of only 12 minutes!!

Thanks and waiting for more...

Manogr
 
Ok....thanks you all....

Everything is clear now after Stephen answer..

Actually this is what I did the times i dive only with tables...I knew the procedure but not the philosophy and I was missing the point of long ascents...

Thank you all !!
 
I would like to just say thanks for bringing up this topic as this is the kind of information that we all strive for .. of couse sometimes it is nice just to joke around.
 
Yes Stephen -- thanks for clarifying.......bad choice of words in that context....plus I've spent too much time recently talking to "techier" diving friends who cut their own tables using specialized software
 
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