From: Charlie_Gibbs@mindlink.bc.ca (Charlie Gibbs)
Subject: Re: how much weight do I need ?
Organization: MIND LINK! - British Columbia, Canada
Date: Thu, 5 Nov 1992 23:55:50 GMT

In article <1992Nov3.192756.355@vestek.com> marcus@vestek.com
(Mark Stephen) writes:

>     I just took a refresher course, and am getting back into diving. At the
>class, the instructor had us bring 10% of body weight plus 12 lbs of weight
>for the dive. For me that was 32lbs. I sunk like a rock. My question is, now
>that I am going to buy my own equip, how much weight should I buy. I have
been
>told by some people that I should be able to dive with 22 or 24 lbs. At
$2.00
>a pound, I'd rather not buy an excess 10lbs, but I'd also hate to end up at
>the ocean and not be able to sink.

     Someone (Abraham Lincoln?) was once asked how long a man's legs
should be.  "Long enough to reach the ground," he replied.  Your
situation is much the same.  Rules of thumb make a good initial
guideline, but a single number fits different people about as well
as an off-the-rack wet suit does.

     The amount of weight you need depends on a number of things.
Two people who weigh the same but are built differently will need
different amounts of lead around their waists.  Even if the same
person switches from an aluminum 80 to a Genesis tank he'll have
to adjust his weight belt.  And everyone needs more weight in salt
water than in fresh, which is why someone properly weighted for the
ocean will plummet to the bottom of a pool.

     The only real way to determine the proper amount of weight is
to experiment.  Start with a decent guess (e.g. that 10% + 12 lbs.)
and try it out.  If you're overweight you can take some off, but
have a few extra weights along in case you need more.  On the first
time out you'll have an instructor with you anyway, and he'll
probably bring some extra weights for just this purpose.  If you're
renting or borrowing a weight belt at this point, you can figure
out how much weight you need before buying your own.

     The general rule is that if you hold yourself vertical in the
water with your BC empty, you should float at eye level when your
lungs are filled, and slowly sink when you exhale.  That's a good
quick initial check.  What you're really after is the ability to
remain neutral at 15 feet with an empty tank.  The air in your
tank weighs about 6 pounds, so at the end of a dive you'll be more
buoyant than when you started.  In addition, a wet suit is more
buoyant at shallower depths than deeper down, so you'll become
more buoyant as you ascend.  You don't want to find that you've
blown a needed safety stop because you couldn't stay down.

     It's better to be slightly overweight than underweight.  Now
before anyone out there gets their flamethrowers warmed up, let
me emphasize the word SLIGHTLY.  You can always compensate for a
couple of excess pounds by putting a bit more air into your BC.
You cannot compensate for inadequate weight (unless you manage to
find a rock you can stuff into your BC).

     Many people are legitimately concerned about coral reefs being
damaged by divers landing on them.  But the answer lies in learning
proper buoyancy control, not in being underweight.  An uncontrolled
ascent can have much nastier consequences than landing on a rock,
however pretty.

>     Any comments greatly appreciated, Marcus

     At least that's my $.0214 worth (adjusted for GST :-)...

Charlie_Gibbs@mindlink.bc.ca
"I'm cursed with hair from HELL!"  -- Night Court

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