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From: pfeiffer@uwvax.UUCP (Phil Pfeiffer)
Newsgroups: net.rec.scuba,net.consumers
Subject: Casio depth rating followup
Message-ID: <248@uwvax.UUCP>
Date: Sat, 27-Jul-85 17:45:48 EDT
Article-I.D.: uwvax.248
Posted: Sat Jul 27 17:45:48 1985
Date-Received: Mon, 29-Jul-85 06:42:54 EDT
Distribution: net
Organization: U of Wisconsin CS Dept
Lines: 60
Xref: watmath net.rec.scuba:156 net.consumers:2725

I received the following reply to my net article on Casio watches from 
Boston University:

>  I Scuba dive and I would NEVER EVER buy a watch not water resistant to 200M
>  That watch is your life.  I would be risking my life to buy a 50M watch
>  and expect to go to any depth.  You deserve to have a broken 50M watch.  I
>  don't know what the big deal is anyhow.  My Casio 200M was only $40 and
>  is now running for 2 years perfectly.  The watch has stayed running longest
>  out of the LCD's that I have owned.  Besides, what do you expect for
>  a watch that is <$50 these days.  When diving it is always better to be safe
>  then sorry.

The author posted the reply to me directly, but I thought it merited public
comment.

First:  I agree completely with the author's main point: false economies are
a bad diving policy.  You risk your health and life when you buy substandard
diving equipment in order to save money.   We do try to be safety-conscious
about what we buy; I apologize for not saying this in in my first posting !!

We goofed when it came to the Casio's.  We failed to read the fine print
in the owner's manual explaining that "water resistant to 50M/100M" didn't mean
"water resistant to 50M/100M" when it came to diving.  My gripe was that I 
thought the statement about the watch being water-resistant was misleading;
why else would you pay extra for such a watch if you didn't want to use it
underwater??   Since both watches worked well down to 50' (15M), we were
really surprised when the 50M watch gave up the ghost 48 hours after the dive
to 82' (24M).   I posted the first article as a warning.

However, I disagree with the author, if he's suggesting that dive watches need
to be rated to 200M to be safe.  According to the U.S. Navy, standard
compressed air scuba can only be used safely to 150' (45M).  The major U.S.
training agencies (e.g., PADI, NAUI, YMCA) treat this as a theoretical limit,
encouraging divers to stay well above 150' (and, parenthetically, urge
divers to take extra training if they wish to plan dives below 60' (18M)).  
Why, then, do I need a watch rated to 200M if I'm not a commercial or a
professional diver?

Postscript:

   Linda has a combination depth-gauge / automatic bottom timer on order now;
I'm going to stop diving with my Casio and buy a bottom timer instead.
If we wanted an even greater margin of safety, of course, we should think
about buying one of the new generation of decompression meters (e.g., the
Edge or the Deco-Brain  (cf. the articles on multi-level diving and the
reliability of the decompression tables in the last two issues of
_Underwater USA_).  These meters still cost $600 and up !!!, but I can see the
day coming when NOT diving with a decompression meter will be also viewed as a
false economy.

[BTW, anyone else on the net have any experience with the new generation
decompression meters?]

-- 

-- Phil Pfeiffer

"Call all hands to man the capstan/ See the cable running clear/
 Heave away, and with a will, boys/ For New England we will steer." 
	                                                        [Ed Trickett]