Mailing List Archive

Mailing List: techdiver

Banner Advert

Message Display

To: techdiver@terra.net
From: iantdhq@ga*.ne* (iantd)
Subject: george again limits
Date: Mon, 2 Oct 1995 10:28:59
cc: iantdhq@ga*.ne*
George
Wow I just returned from Androus diving blue holes, you would have loved it 
sorry you were not able to get free to join us,. We found some new stuff and I 
hope you can go with me in April.

I was shocked to read you guys got ripped again, I would bet it is the same 
source who hit you before. I guess a part of cave diving today is to hire 
security guards while you are in the water. Maybe you should borry my rotties 
They think arms and legs taste good. Anyone who would steal from a project 
especially if I read it right , while you were in the water, should be 
cooked slowly in boiling water as they are a threat to the safety of 
the divers.

On gas, george I started doing mix dives some 30 years ago. We had a mix 
heliox program at UM RSMAS from 1971 to 1976 with research dives to300 feet. 
Billy Deans started doing mix dives in 1988 or early 89. IANTD developed its 
trimix program in november of 1991. The orginal instructors who all dived gas 
of course were Sheck, myself, Billy Deans, etc, With Badden, Stocks, Ramio, 
and Berman soon to follow and since then of course JJ and numerous others. 
We started this program with great concern and we have grown with it to the 
point of encourgaging all who intend to dive deep at least those going deeper 
than 180/57 meters(open water) 160 feet/54 meters to use trimix. We think it 
is the only safe and predictiable choice for dives below 200 feet /60 meters.

On limits in recreational no stop dives we do use NOAA limits and think they 
are quite safe for MOD we plan POD (planned operational dive more shallow) 
Even in basic EANx we state 1.6 max/limit for working dives 1.4 ata. Outside 
of the USA we use 1.5 ATA as a max. Someday within the USA we will also but it 
takes more than my decision to accomplish that.

In tech diving we use a CNS percent table that follows quite closely to Bill 
Hamiltons and Randy Bohrers OLI index. Tghis allows a 1 minute safe limit at 
1.82 ATA - 10 minutes at 1.7 ata,  20 minutes at 1.62 ATA and then picks up on 
the NOAA limits. We track % of toxicity with 100 % being the maximum safe 
exposure for a total dive duration based on average population. 

We encourage divers to avoid 1.6 ata for stops longer than a minute or two.  
We advocate EAN 80 at 30 feet/9 meters po2 of 1.53 ata. We have made runtime 
tables that use EAN 78 at 30-20 and 15 feet/9,6 and 3 meters (our new tables 
have dropped the 10 foot stop, this alows the 20 foot / 6 meter stop to clear 
faster as the diver only ascends to 15 feet 4.5 meters not 10feet / 3 m3eters 
and we also did it as most of us did not go to 10 feet in open water anyway 
due to sea conditions{ in caves yes I did go to ten feet} and from a math 
standpoint there is a possibility of model violation, thus we decided on a 
model that followed the  practice of many tek divers)    We also have 
aceklerated tables for stops at 20 and 15 on EAN 75 or above these alos use 20 
and 15 foot stops. For those who still insist on using oxygen at deco both 
these tables get them off the 1.6 ata quickly and up to 15 feet with a 1.45 
ata po2.

Tom
I hope this community is good enough to discover the "villian " who rips off 
dive gear.

Also, I hope your statement has some exceptions in it as I really do hope to 
dive up there.

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]