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Chuck: You point some interesting things here...my comments below where suitable... >---------- >De: CHK BOONE >Para: >Asunto: Re: OMS wings problems >Fecha: Viernes 20 de Marzo de 1998 18:00 > >Sender: owner-techdiver@aquanaut.com >Received: from bighorn.terra.net (bighorn.terra.net [199.103.128.2]) > by hil-img-2.compuserve.com (8.8.6/8.8.6/2.10) with ESMTP id MAA25015; > Fri, 20 Mar 1998 12:00:06 -0500 (EST) >Received: (mail@lo*) > by bighorn.terra.net (8.8.6/jr3.9) for > id LAA25038; Fri, 20 Mar 1998 11:31:04 -0500 >Precedence: bulk >Errors-To: owner-techdiver@aquanaut.com >Received: from bighorn.terra.net (root@lo*) > by bighorn.terra.net (8.8.6/jr3.9) with EXEC for techdiver > id LAA23709; Fri, 20 Mar 1998 11:06:58 -0500 >Received: from imo16.mx.aol.com ([198.81.17.38] (may be forged)) > by bighorn.terra.net (8.8.6/jr3.9) with ESMTP for <techdiver@aquanaut.com> > id LAA23697; Fri, 20 Mar 1998 11:06:52 -0500 >Received: from CHKBOONE@ao*.co* > by imo16.mx.aol.com (IMOv13.ems) id ASOEa11675 > for <techdiver@aquanaut.com>; Fri, 20 Mar 1998 11:05:26 -0500 (EST) >From: CHK BOONE <CHKBOONE@ao*.co*> >Message-ID: <d094f90.351293c9@ao*.co*> >Date: Fri, 20 Mar 1998 11:05:26 EST >To: techdiver@aquanaut.com >Mime-Version: 1.0 >Subject: Re: OMS wings problems >Content-type: text/plain; charset=US-ASCII >Content-transfer-encoding: 7bit >X-Mailer: AOL 3.0 for Windows 95 sub 62 > > >Jim, > > You write: > >>Using the DS as primary is done by lots of divers. I don't think its a >>bright idea, certainly not comfortable, but to each his/her own. Using >>your wings as primary is the ideal, if you have to use your DS, you deal >>with it. > > The reason I asked "why not" is because I thought the answer would >probably be that Dry Suit buoyancy control was in some way less efficient, >comfortable, safe, or practical for many divers but I wanted you to say it >since I have never dove a dry suit and can not speak from first hand >experience. > In winter I use a Viking Sport 80 dry suit that still provides good service, though the cuffs had to be changed, and with this suit I have three choices: 1 Use only the DS for buoyancy control 2 Use only the Wings for buoyancy control 3 Use both simultaneously for buoyancy control 3- Though some friends use a modification of 3, they fill the DS enough to avoid squeeze and then use the wings for buoyancy control, I'm not conviced as it implies having to control two air volumes. While I don't doubt that it can be done well with practice, I'd rather worry only about one air volume. I certainly wouldn't fill both for buoyancy control simultanously unless it was for an emergency (rescue or similar). 2- With a membrane suit such as mine this option is not feasable as the squeeze is most uncomfortable, and if the underwear is not thick enough, painful and harmful. 1- I leave the wings empty, and use the DS for buoyancy control. At first it felt odd, but now I feel comfortable with it, and I have a reliable set of wings for emergency buoyancy control. In summer, unless doing deep dives, I use a five milimetre hooded wetsuit , then I have no choice but to use the wings for buoyancy control, and I'm happy with them. If I feel the dive doesn't call for the DS, but is below 40 mts (135 feet), I may decide to take two bladders. In other words, my winter "secondary" is my summer "primary". Thus should my DS develop a leak, or should its inflator fail, I have a "secondary" that is really a "primary" buoyancy control system. The idea of "primary" and "secondary", often it brings about good - bad associations , as with good primary regulator, bad secondary regulator. Perhaps that is why I don't like the terminology, and the subliminal message it may give. Conceptually, both my regulators are "primary", and in all dives I breathe for approximately the same amount of time from each one. If I ever hand one to someone I KNOW it works, as I keep both at neck height when not in use, so they are less prone to gather sand, silt or gravel. So I must agree with you here: > Whatever back up systems we use in diving should be as good or better than >the primary in every respect because this is what actually determines our >limitations - not the primary system. Except that the wings cannot completely replace a DS, only for buoyancy control, but not for warmth! I'm afraid I haven't found the perfect system yet.... Regards Conrad >----------------------------------------------------------- >>In many critical backup systems there is a "get home" strategy and this >>includes parachutes, brakes, engines (like a twin engined airplane), >>pumps, to name a few off the top of my head. > >>The idea being that the primary system is extremely unlikely to fail, but >>just in case a secondary "get home" system is available. > > And, where getting back alive and well is a high priority, the limits of >safe penetration (up, down, or sideways) are dictated by the capabilities of >the diver using the "get home" system during a bad storm rather than by his >capabilities with the primary system on a nice day. I'm sure this is >violated as a matter of course with many divers at all levels such as when >they buy a cheap octopus. > I think it is unwise for a diver to think in terms of "getting home" as a >pilot in a crippled plane does when he gives up trying to fly and jumps out. >The diver must continue to fly somehow no matter what. We must "dive" our way >out of trouble without the luxury of shifting to an escape mode that frees us >of the burden of having to continue to perform under pressure. > > It seems to me that choosing to use a dry suit for back up buoyancy is to >limit yourself to what you can safely return from using dry suit buoyancy >control. So, for the diver to whom the bladder is the superior method of >buoyancy control, a second bladder would extend your safe range to what you >can do with a set of wings. I am assuming, of course, that there will be >some deterioration of your performance and endurance or in your status if you >have to resort to a system you don't like or prefer for some reason.> > > I can't really see a problem with a second hose safely tucked away but >accessible, though I would do away with the LP hose as I have noted. This >would not violate hogarthian thinking if it were needed to make the intended >penetration safer though it might cause problems with some specific >configurations that also adhere to hogarthian ways. > The WKPP rig is an excellent interpretation and application of hogarthian >philosophy but so is a well designed submarine if the dive requires that you >go to 3000 feet. The hogarthian philosophy is a stand alone tool >universally applicable to a wide range of situations from the new diver to the >sub pilot. It is not the WKPP or any other specific configuration as some >might come to think from the tone of the tech lists. > You know, if you guys could get over your fear of the dark you could dump >those big AUL light canisters you haul around and another inflator hose won't >be such a big problem. > > >------------------------------------------------------ >> Now if the bladders in wings were popping like zits on an adolescent's >> face, well maybe you have something with dual bladder wings. > > Yes, you would have dual junk ! "Dual bladders" is only a worthwhile >back up strategy if failures are rare and not caused by factors normally >common to both sides. >You've got to be able to trust a back up system to get you back out all the >way in less than ideal conditions and task loaded. Starting out with a >bladder with a known propensity to pop (even if the second is less likely to >fail) means that your poorly chosen two is not even one (two is one and one is >none). > > Whatever back up systems we use in diving should be as good or better than >the primary in every respect because this is what actually determines our >limitations - not the primary system. This system is made up of a combination >of the diver and the equipment he will be using so that everything about the >divers head and body effects the performance of the system as much as does the >equipment suitability. > No doubt the reduced clutter of using the dry suit as back up is preferable >but only to the limits from which you can return with it safely. > >> But even then I would argue that it makes more sense to design a reliable >> primary rather than having identical redundant systems to make up for >> some design deficiency wether real, or as in this case, imagined. > >What I am suggesting is two systems you have equal faith in and capabilities >with rather than one you like and one that is a compromise for some reason. >Otherwise limit your range to what you can handle easily on the compromise >under stress. > > >Chuck Boone -- 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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