X-Envelope-to: SCUBA-L@BROWNVM.BITNET
X-VMS-To: IN%"SCUBA-L@BROWNVM.BITNET"
Newsgroups: bit.listserv.scuba-l
Date:         Tue, 13 Oct 1992 09:41:00 EDT
Comments:     Warning -- original Sender: tag was WVANDERCLOCK@BENTLEY
From:         WVANDERC@BENTLEY.BITNET
Subject:      Re: To compute or not to compute

*On the accounting of safety stop time for using tables, I wrote

>> But not so for PADI Dive Tables, if you follow their prescriptions.  In
>> fact, if you SURFACED for 9 minutes and re-entered water to dive, you're
>> still in the FIRST dive.  That's what prompted my comment

>> Also, Tables do not account the first 10 minutes of
>> your surface interval in repetitive dive-group computations, ...

*"(Nicholas J. Simicich)" <scifi]njs@UUNET.UU.NET> said,

> The instructions that came with my Wheel do not make any mention of
> this.  As far as I can tell, your next dive starts as soon as you
> surface.  Or perhaps I've just missed it?  Other people have looked.

*I had mentioned

>>  Just look at any PADI or NAUI Surface Interval Time/Credit Table.  The
>>  minimum time starts at 0:10 because of the DEFINITION of a DIVE.

*"your next dive starts as soon as you surface" does not apply even to
*COMPUTERS.  Nick, look up your COMPUTER manual(s), and see how it counts
*dives.   However, computers, unlike tables, DO continuously credit surface
*interval time, irrespective of the def. of the dive number.

*When I used the term "dive tables", I was referring to the generic,
*rectangular plaster cards called "tables", and implicitly excluded the
*Wheel.  I quoted in the same post the source of my comment about the
*10-minute surface interval (or not counting the first 9):

>> "If a surface interval is less than 10 minutes, treat the dives as a single
>> dive, adding the Bottom Times together and using the deepest depth attained
>> on either dive to determine the Group Designation."

*The quote was taken from MY latest PADI Diver Manual (1984, p.120) which was
*written before the Wheel (which some call "Wheel of Fortune" and some call
*"Bend-O-Matic"  :-) ) was invented.  I don't think the conventional
*definition of a dive or the use of those tables have changed since 1984.

*-- Bob.


It is VERY important that anyone reading this stuff understand that there is no
such thing as "generic dive tables" anymore.  PADI departed from tables based
on the US Navy tables several years ago, not just for the wheel, but for ALL of
their tables.  This means that the "conventional definition oa a dive or the
use of those tables" has changed substatially since 1984!  Regardless of how
you feel about PADI, they do certify more divers than anyone else so the impact
of this change in the tables has far reaching effects.

My point is that when you dive with someone, part of your dive planning needs
to be a decision about which tables to use since old PADI tables don't match
new PADI tables which don't match NAUI tables that differ from SSI tables (NAUI
also departed from the USN tables I believe) that probably differ from YMCA
tables.   Diving like everything else is always changing and although most
changes are optional, it pays to keep up with the changes so you at least know
why you don't want to change.

Bill VanderClock           PADI OWSI #200330
WVANDERC@BENTLEY           "Professor Deep"
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU