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Alan, When you finish your dive you should be neutral at 10-20 ft (where you do your last / safety stop) with your ending gas supply (500psi?) in your tanks. That means that when you start you will be 7 # (aul 80) - 10# (stl 120) negative with singles to 14# - 20# negative with doubles due to the gas weight in your tank(s). Therefore you need to add this much buoyancy to your wings to offset this. This air in your wings will have to be increased as you get to depth and then decreased as you use your gas supply and later decreased as you ascend. Get in the water with your drysuit on and get neutral - then put on 20 more # of weight and see how much air you have to add to your suit to get neutral again - a lot. This is the problem. Use your wings for what they are for and your suit for what it is for - it can provide backup buoyancy in an emergency but don't use it for primary. Dave ----- Original Message ----- From: Alan D. Secor <secor@bt*.ib*.co*> To: Kurt Kauth <kkauth@wo*.at*.ne*> Cc: Ted Phelps <tphelps@ph*.co*>; Peter Fjelsten <fjelsten@ma*.do*.dk*>; Jim Cobb <cobber@ma*.ci*.co*>; <techdiver@aquanaut.com> Sent: Friday, March 17, 2000 3:04 PM Subject: Re: How to shoot a lift bag / trim problem > 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. > > > >-- > >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > > >-- > >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > > >-- > >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > > > -- > Alan D. Secor > e-mail: secor@bt*.ib*.co* > > > -- > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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