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To: "Kurt Kauth" <kkauth@wo*.at*.ne*>
cc: "Ted Phelps" <tphelps@ph*.co*>,
     "Peter Fjelsten" ,
     "Jim Cobb" , techdiver@aquanaut.com
Subject: Re: How to shoot a lift bag / trim problem
Date: Fri, 17 Mar 2000 15:04:06 -0500
From: "Alan D. Secor" <secor@bt*.ib*.co*>
I've been following this thread and you guys who advocate using the wings 
for buoyancy seem to be missing a simple point.  Let's say you trim 
yourself to be neutral at say 20 ft with just enough air in your suit to 
keep you warm.  Now, assuming you are in cold water, there will be a fair 
amount of room taken up by the undergarments and air inflation.  As you 
descend, the air in your suit will compress and theoretically to maintain 
the same volume of air in the suit you had at 20 ft, you will have to add 
more air to the suit.  Once you're back to the same air volume you had at 
20 ' you should also be neutral.  Therefore, you should never have to 
touch your wings once you first establish neutral buoyancy at a given 
depth since all you will be compensating for is loss of air volume in the 
suit.  You also shouldn't end up with a huge ballooning suit at depth 
since you are only maintaining the original air volume of the suit.

Where am I wrong with this argument??

Al

>Use the wings for buoyancy and the suit for warmth.  Most instructors teach
>that the drysuit is used for inflation.  The reason they teach this is
>because you have to have air/argon in the suit to keep warm.  They also know
>that they are teaching to the lowest common denominator strokes that can't
>handle two things at once under water like dumping the air from the wings
>and drysuit simultaneously. Therefore, in order to solve the warmth problem,
>they use a workaround in order to prevent a rapid ascent situation when the
>student loses control.  This is how I was taught, but very quickly learned
>what a bunch of crap it was and to use the BC for inflation (before I got
>smart and got wings).
>
>The other main reason is drag.  By inflating the wings, they rise up and out
>of the way and stay in the water slipstream as you swim along, minimizing
>drag.  If you use the suit for inflation you lose this advantage and
>increase your drag.
>
>Bottom line - you want enough air in the suit to keep you warm and prevent a
>drag and then use the wings for your buoyancy control.
>
>Kurt
>
>-----Original Message-----
>From: Ted Phelps [mailto:tphelps@ph*.co*]
>Sent: Wednesday, March 15, 2000 10:05 AM
>To: Peter Fjelsten; Jim Cobb
>Cc: techdiver@aquanaut.com
>Subject: RE: How to shoot a lift bag / trim problem
>
>
>I'd really appreciate some feedback here, because I get conflicting opinions
>both here and amongst the divers with whom I hang out.  Some say to use the
>drysuit for buoyancy, leaving the BC deflated, except on the surface, while
>others are saying nearly the opposite.  I've done two drysuit dives, having
>done all of my other dives in Hawaii.  I'm back home in California, and my
>drysuit is on order.  Can anyone give me some guidance?
>
>Ted
>
>-----Original Message-----
>From: Peter Fjelsten [mailto:fjelsten@ma*.do*.dk*]
>Sent: Wednesday, March 15, 2000 3:54 AM
>To: Jim Cobb
>Cc: techdiver@aquanaut.com
>Subject: Re: How to shoot a lift bag / trim problem
>
>Den 14-03-00 11:45 -0500 skrev Jim Cobb (At 14-03-00 11:45 -0500 Jim Cobb
>wrote)...
>>Sounds to me that you have too much air in your drysuit. You need to keep
>as
>>little air in your DS as possible and use your wings to control your
>>buoyancy. Then you are "hanging" from your doubles and and your rig won't
>>slip.
>
>I continually read this on TD.
>
>OK you warm water people - when you dive really cold water you wear more
>undergarments than in 20 C water. Therefore the suit holds more gas than in
>warm water. Also, you want to keep a fair amount of gas in the suit to stay
>warm. Therefore "as little as possible" to prevent squeeze definitely is
>less
>than to keep warm.
>
>Please keep this in mind.
>
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--
Alan D. Secor
e-mail: secor@bt*.ib*.co*


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