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thanks for the info, i really appreciate it. but i was wondering how do you
determine how much lift is required from your bcv?? you mentioned the
halycon outfit that has 36 lbs of lift. how do you choose how much lift
youll need when you buy your vest?? im looking at hopefully buying one vest
that will accomodate several different type of diving. but mostly rec diving
and maybe an occasional wreck dive. but it depends on how hooked i get into
this new sport for me. thanks, tim.
----- Original Message -----
From: "David Strike" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, February 20, 2001 12:52 AM
Subject: Re: FYI - Cozumel Conditions


> On Tuesday, February 20, 2001 5:05 PM, Tim wrote:
>
>
> > since im a newbie, ive got some more questions. what the difference
> between
> > the 1st and 2nd stage for a regulator??
>
> In simple terms the purpose of the regulator is to reduce the pressure of
> gas contained in a cylinder down to a level comfortable enough to keep
pace
> with the diver's breathing requirements.  It achieves this in two stages.
> The first stage reduces the pressure of the cylinder contents down to an
> intermediate pressure that remains at approximately 10 bars above ambient
> pressure.  This pressure is further reduced by the action of the
regulator's
> second stage, or demand valve, to provide easy and effortless breathing.
>
> Although all scuba regulators follow these basic principles the method
> varies according to the type of first stage used.
>
> Without delving too deeply into the mechanics, regulators fall into one of
> two broad categories, Balanced and Unbalanced, each of which has its own
> distinct characteristics and sub-types.
>
> In the Unbalanced Regulator, both cylinder pressure as well as ambient
> pressure acting on the first-stage mechanism will determine the gas flow
> available at the intermediate stage.  Now usually governed by a piston
> assembly and employing a relatively small orifice, an unbalanced regulator
> is limited in the amount of gas that it can deliver, particularly when the
> cylinder pressure falls.  In the shallower diving ranges (less than
> 30-metres), this is seldom a hindrance but can become more problematic at
> depth or in an air-sharing situation.
>
> Usually employing either a diaphragm or a piston, a balanced regulator has
a
> much larger orifice and relies on mechanical forces rather than cylinder
> pressure to deliver a high constant pressure of gas.   A characteristic
that
> makes it more suited to deeper diving and high exertion swimming.
>
> >also, how do you calculate for the
> > lift capacity for the bcv?? thanks, tim.
>
> Because we use a metric system, I find it easier to calculate.  As a rule
of
> thumb,1 litre of water = 1 kg of lift.  Topping the BCD bladder up with a
> measured amount of water makes it easy to calculate its potential lift
> capacity.   :-)
>
> Strike