Joel

Thanks for the information, most of which I was aware of.

When I mentioned standard tables, I was referring to the idea of choosing a
set of bottom gas mixes for specific depth ranges and then developing your
own standard tables for these mixes and deco gases the individual uses.
Thus, cut the tables once and they can be re-used.  The main problem with
generic tables of the nature you mention is that you'll end up doing far too
much deco than is necessary.

David Shimell
Project Manager, Sequent Computer Systems Ltd., Sandton, South Africa.
Email: shimell@se*.co* <mailto:shimell@se*.co*> 

-----Original Message-----
From:	Joel Silverstein [SMTP:joelsilverstein@wo*.at*.ne*]
Sent:	Wednesday, September 30, 1998 4:44 PM
To:	David Shimell (shimell); s_lindblom@co*.co*;
techdiver@aquanaut.com
Subject:	RE: Trimix question - Real Tables 

David, 

There are standard tables for standard mixes ---Hamilton Research Ltd has
had standard trimix tables avaialble for years 

they are the Key West Consortium Tables -17/50/33 

Variable Oxygen Variable Helium tables for Trimix from 120 fsw - 250 fsw 

The single set of tables allow for the use of 16-21% oxygen  17-50% helium
content

Required decompression gas is EAN36 and Pure Oxygen. 


There is a variation of these tables for shallower water diving and single
gas decompression 

Key West Consortium 18/35/47   

For depths of 130fsw - 230fsw 

This single set of tables allow for the use of 18-21% oxygen 30-40% helium

Required decompression gas is EAN 55-65     oxygen is optional

These tables are exceltional, are used by many many divers, and are quite
expensive, however they have an extremely reliable track record and
eliminate the need for making up new tables every time you want to do a
dive -- they also allow for mix variables which makes them wodnerful to use
on expeditions. --- No batteries needed. 




At 03:07 PM 9/29/1998 +0100, David Shimell (shimell) wrote:
>All
>
>>If one were going to use trimix in the deep rec/lite tec range,  as many
>>have been advocating here, for moderate exposures, ,  say, 100-160', 20-40
>>minute bottom, and wanted to have a fairly standard mix to use rather than
>>doing a different mix for every dive, what would one use?
>
>As a slight digression, it is worth developing standard mixes and tables
for
>ranges of depths and times.  I dive mixes for every 10 m, i.e. I use 50,
60,
>70, 80 metre mixes together with the corresponding tables... My run times
>are also in 5 minute increments (easy to remember)  - usually 3 options
with
>the middle run time being the planned run time.  This RT is usually set at
>around 90 minutes due to the water temperature in the UK.
>
>My tables for my 80m mix (16/44) go in 5 metre increments i.e. 80, 75, 70,
>65, 60, 55, 50.  Thus if we mix for an 80 metre dive and weather precludes
>diving this wreck, and we have to do a 63m wreck, then I would simply dive
>my 65 m tables for this gas.
>
>For multiple day diving, I see a penalty of around 4 minutes maximum.  I
use
>the same tables but add in a minute here and there (one minute 3 m deeper
>than my first mandatory stop, 1 minute in the middle somewhere and 2
minutes
>on my last stop at 6 m.  This is in addition to 10 m/minute ascents and
deep
>stops added.
>
>My tables are laminated and therefore re-usable.
>
>David Shimell
>Project Manager, Sequent Computer Systems Ltd., Sandton, South Africa.
>Email: shimell@se*.co* <mailto:shimell@se*.co*> 
>
>--
>Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
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>
Joel D. Silverstein
Scuba Training + Travel Co.
http://www.NitroxDiver.com
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