hogg@utcsri.UUCP (John Hogg) (08/01/85)
First, my qualifications: almost no diving for the past four years. (It
cuts into the sailing season too much, and the water here is cold and
dark.)
Rich Schiraldi expressed a strong opinion that decompression meters were
not just useless, but dangerous. This was in response to Phil Pfeiffer's
speculation that someday " NOT diving without a decompression meter will
also be viewed as a false economy".
With the current state of the art, Rich is right in claiming that SOLE
reliance on a meter is dangerous. However, the first anecdote that he gave
was clearly an example of equipment failure, and I can hunt up equally
horrifying stories of regulators packing it in. The second may have been
equipment failure or merely bad design.
In either case, "someday" the bugs will be reduced to a level acceptable in
regulators, and tables will be obsolete. Let's face it: a sufficiently smart
device can produce a better answer by simply taking into effect more
information, if we can come up with a good model of the bends. The tables
ignore temperature, breathing rate, diver physiology and who knows what else.
This information can be automatically or manually entered into a micro-based
simulation of nitrogen saturation, and produce a far more accurate
decompression schedule than those we currently use.
This is especially true when we remember that the tables do not guarantee
safety; a certain percentage of divers WILL be hit if they use the tables
right to the limits. The U.S. Navy has fit divers and often recompression
facilities, and is willing to take chances. Sport divers therefore decompress
conservatively, because the model they're using is so bad. Improving the
model by using more data can only be to the good.
--
John Hogg
Computer Systems Research Institute, UofT
{allegra,cornell,decvax,ihnp4,linus,utzoo}!utcsri!hogg