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Yes, you are correct.  The IANTD tables are flawed and
wrong.  I once did the same exercise, and spent several
hours trying to figure out where my calculations were
wrong.  It turned out the problem was in the IANTD gas-matching
tables. 

-Will

On Tue, 16 Dec 1997, Imdamaged wrote:

> I recently found this tech diver list.  Man you guys are mean!!!!  All this
> talk is about diving ?  There MUST be a WOMEN involved somewhere to generate
> this type of animosity. ANYWAY..
> 
> My post is about Gas matching as presented in the IANTD Deep Air Text.  The
> book describes a method of calculating the required adjustment to the rule of
> thirds for a penetration dive for a pair of two divers.  The IANTD solution
> involves working through a series of tables to determine the "turn pressures"
> for the divers.  
> 
> I attempted to verify and regenerate the tables using a spreadsheet and found
> that the solution presented by IANTD in the Deep Air Text is not correct.  
> 
> The error in the solution is that sometimes the answer is correct and
> sometimes it is around 15% conservative depending on the relative tank volumes
> and RMV's of the individual divers.  The diver using the IANTD tables seems to
> have no way of determining when the solution is exact (i.e. no magin for
> error) and when it is conservative. 
> 
> I have written a simple spreadsheet solution to get the answer correct.  It
> would seem that a diver using this technique could add a known safety factor
> rather than an unknown or non-existant one as is supplied by IANTD.  
> 
> I have provided documentation of the problem to Tom Mount and IANTD quite a
> while ago and have received no response.
> 
> Does anyone really use the IANTD method?  Does anyone want to do it correctly
> with a spreadsheet?  Is this just petty BS that the experts know about
> already?
> 
> Jim Fyfe
> 
> 
> 
> Jim Fyfe
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