Posted by PTF on September 25, 2001 at 12:42:13:
In Reply to: Re: Dive Computers-Really Long posted by Jon D on September 25, 2001 at 11:21:41:
The following is from my archives and is from another
BBS. The board is a bit more technical and just as highly charged
as this one. Thus you will see mention of Helium. I also sanitized
some of the Marine DI language.
ptf
mid 2000 with updates of 29jun01
40690
Computer Diving
Divers have three primary methods by which to calculate dive and/or decompression time. These methods include the
use of tables, wrist mounted computers, and personal computer decompression programs. Substantial debate exists
over the use of wrist mounted decompression computers. These computers are worn by divers and calculate dive
time limitations and decompression obligations during the dive. Some educators have discussed abandoning the
learning of decompression tables, which is very similar to eliminating the teaching of basic math skills such as addition
and subtraction instead using a calculator.
The most obvious problem with diving computers is that divers could be left without essential diving information
should the diving computer fail. Many divers prefer to learn the proper use of decompression tables striving to learn
the actual process of decompression diving. Divers that choose to use computers should do so after becoming well
versed in the diving limits and then using the computer primarily as an educational tool. The following list includes
concerns about decompression computers.
1) Dive computers tend to induce significant levels of diver
dependance, eliminating the awareness so common and essential to
all diving but particularly obvious when divers begin decompression
diving.
2) Dive computers do not allow proper planning, as divers can't
properly "study" the impact of various mixture and decompression
choices.
3) Dive computers are of very limited educational benefit as they
do not induce questioning, or proper planning discussions as can be
found with tables and most particularly with PC based decompression
programs.
4.00) Dive computer programmers often play games with computational
process so that they can (take) insulate themselves from the risk of
taking largely square profile data and utilizing it on a multilevel
dive. These games tend to result in odd and often ridiculous levels
of conservation.
4.01) Many real time dive computers use algorithms that heavily pad
decompression time, sometimes resulting in odd and often ridiculous
levels of conservation.
5) Dive computers are expensive and in some cases leave divers with
limited resources carrying equipment that is of far less benefit
than other equipment that may have been purchased.
6) Dive computers significantly limit the likelihood that divers
will track their residual nitrogen groups, leaving them
less informed in the event of computer failure.
7) Dive computers do not allow for Helium diving in any formats
but the bulkiest and most questionable format. It is very likely
that new Helium based decompression computers will be inordinately
conservative and suffer from all the limitations of air and nitrox
diving computers.
8) Dive computers will often generate longer decompressions than
could be figured by an astute, well educated diver with experience.
9) Dive computers often create confusion by giving the user to much
useless information, sometimes even obscuring depth and time in
favor of blinking CNS and/or deco limitations.
10) Some dive computers become very difficult to utilize if a deco
stop has been violated. Some computers lock up completely while
others just beep or generate erroneous and distracting information.
(Divers using mixed gasses are likely to often violate computer
profiles.)
11) Dive computers do not allow for the educated diver to properly
modify their decompression to account for advancing knowledge such as
the use of deeper stops in a decompression profile.
12) Dive computers do not offer divers as much flexibility in the
generation of profiles with varying conservation. For example the
right mix would allow 100 min at 60 vs 60 at 60 but the diver might
prefer to do one or the other and indeed might like a compromise.
Computers confuse this issue by not providing divers with the proper
information.
13) Dive computers users often ignore table proficiency and therefore
do not learn tables properly. When confronted with a situation where
they can't dive the computer (failure, loss, travel etc) these divers
are at a serious handicap.
Jarrod Jablonski
just a quote from one of the members
"Yes, I am an agent of Satan, but my duties are largely ceremonial"
43237
From: "Thomas Tukker"
Subject: RE: Oxygen Toxicity - using 100% in open water
Date: Tue, 13 Jun 2000 19:15:16 -0400
Scott,
The biggest reason not to use a dive computer is because you do not need a
dive computer.
You do not need it to make an efficient deco dive
You do not need it to teach you deco
You do not need it to die on you
You do not need it to tell you that you violate it's programmed nonsense
You do not need it to beep
You do not need it to give you wrong information
You do not need it to make life "easy" for you
You do not need it to tell you what your SIT should be
You do not need it to tell you how much air time you have left
You do not need it to have a fxxxing H.U.D.
You do not need it to tell you depth
etc...
Now, can you give me one good reason why I need it?
THOMAS