Mailing List Archive Mailing List Archive
John: You wrote: >I have recently had the opportunity to take some fairly old BCDs apart >(3 of them). These were all, I would guess, in the region of 20 years >old. One of them had a bladder failure where the plastic seal holding >the inflator hose had disintegrated. The other 2 bladders had all the >attachments held by screw fittings (i.e. one piece inside the bag, one >outside) and were serviceable. The actual plastic used for the >construction for all 3 bladders was sound. Here's what has appeared in list so far: Regarding BC failure points: Chuck Boone points out a possible cause of bladder damage: > Any spot where salt crystals can collect can suffer from accelerated >abrasion. Watch for this between the bladder/s and the outer covering of >wings. Jacket styles that do not have a bladder are only waterproofed with a >coating inside the nylon jacket that is easily worn away by such abrasion when >opposite walls rub against each other. Flush these out well and keep them >partly inflated for storage AND transport where feasible. This is the kind of >invisible ware that can catch you by surprise during a dive - easily avoidable >- easily overlooked. Mike Wells says: >I have personally had two older US Divers bladderless BCs (pre SeaQuest >manufacture) fail and have heard of others doing the same thing. The >inner airtight lining delaminated from the outer material causing leakage >through the nylon material. In neither case was this a major air loss, >but it was time to retire them. I wonder if Chuck's salt crystals played a role here... but Mike also says: > I would definitely agree >that the most common failure would be the inflator and/or hose. On the other hand Lee Gibson mentions that his buddy : >had a total BC failure. He was wearing double 104's and a wet suit. At the >"three way split" the seam of his bladder failed with a total loss of >buoyancy. However, complete failures such as described seem to be exceptional, as Jim Cobb has written: >I have personally never seen any BC fail. I have seen a couple of LP >inflator hoses fail, invariably right as the tank valve is opened. I have >heard of inflator valves sticking open, the couple I have heard were on >rental gear or they were frozen (ice diving). I heard one story of the >inflator hose popping off the BC.In other words they were maintenance >issues. He is corroborated by Glenn E Goettler who has only seen inflator problems: >...in my 3 years as equipment manager for a university dive club (RPI), the >biggest problems we had w/ the BCs was the power inflator. the o-rings >would start to degrade due to heavy use and chlorine, and would leak. we'd >also get a lot of sand and silt jammed into the buttons, causing more >fowling or sticking. surprisingly, we never had any problems with the >bladders, OP/dumps, and these were cheap, bladderless jacket type BCs.> And by yourself: >I have only personally had one problem with BCDs, again the inflator >hose (blocked filter). It was only because I didn't address the problem >as soon as I noticed the decrease in performance that this was an issue Although the experience of six persons doesn't provide statistical value, this data does allow us to draw a few hypothesis (not yet certainties, nor dogmas): 1- Inflator systems are the no. 1 source of trouble in buoyancy systems. 2- This is more often than not caused by lack of maintenance or invasion by foreign particles (sand, etc.), and can involve free-flow or a blockage. 3- Bladders or bags rarely burst leaving one without buoyancy, but it does happen. 4- If either of the two things happens in the wrong place, one better have some alternative system both for breathing and for buoyancy compensation. Blockage can be solved by oral inflation, free-flow inflation by disconnecting the hose and or closing the regulator's valve. A burst bladder can be replaced by an alternate system (dry suit or a second bladder). 5- Apart from bursting, some bladderless BCs delaminate. But this will probably result in a slow leak rather than a total immediate loss of buoyancy, unless damage is enormous and maintenance is nonexistent. This also seems to affect specific models which are no longer in production. 6- Damage from salt crystals (interior & exterior damage), or abrasive or cutting matter from overhead environments (exterior damage), can damage or weaken the BC. This interior salting could help speed the delamination process. Again rinsing by the user (user maintenance) will reduce the problem. Thanks to all for the info. If anyone wants to add more info, please feel free to join. Conrad >--------- >De: "Taylor, John" >Para: Tech Diver >Asunto: RE: OMS wings problems >Fecha: Viernes 20 de Marzo de 1998 9:32 > >Sender: owner-techdiver@aquanaut.com >Received: from bighorn.terra.net (bighorn.terra.net [199.103.128.2]) > by arl-img-6.compuserve.com (8.8.6/8.8.6/2.10) with ESMTP id DAA05650; > Fri, 20 Mar 1998 03:31:53 -0500 (EST) >Received: (mail@lo*) > by bighorn.terra.net (8.8.6/jr3.9) for > id DAA07647; Fri, 20 Mar 1998 03:18:45 -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 VAA29800; Thu, 19 Mar 1998 21:48:33 -0500 >Received: from bas01.csfb.com (bas01.csfb.com [198.240.130.164]) > by bighorn.terra.net (8.8.6/jr3.9) with ESMTP for <techdiver@aquanaut.com> > id VAA29792; Thu, 19 Mar 1998 21:48:32 -0500 >Received: (from mailuser@lo*) > by bas01.csfb.com (8.8.8/8.8.8/EXT) id VAA07922 > for <techdiver@aquanaut.com>; Thu, 19 Mar 1998 21:50:36 -0500 (EST) >Received: from unknown(169.39.5.57) by bas01 via smap (3.2) > id xma007905; Thu, 19 Mar 98 21:50:06 -0500 >Received: from lmssmtp1.corpny.csfb.com ([169.37.98.134]) > by csfb1.fir.fbc.com. (8.8.8/8.8.8) with ESMTP id VAA21935 > for <techdiver@aquanaut.com>; Thu, 19 Mar 1998 21:48:00 -0500 (EST) >Received: from stok00300.csfb.co.jp ([158.216.65.17]) by lmssmtp1.corpny.csfb.com >(8.8.2/8.8.2) with ESMTP id VAA07066 for <techdiver@aquanaut.com>; Thu, 19 Mar >1998 21:47:58 -0500 (EST) ; g john.taylor@cs*.co*.uk* >Received: by STOK00300 with Internet Mail Service (5.0.1458.49) > id <HCJQGHQ3>; Fri, 20 Mar 1998 11:47:56 +0900 >Message-ID: ><F54AF0FE9117D111AF5900805F0D987D1ECE01@sh*.cs*.co*.jp*> >From: "Taylor, John" <john.taylor@cs*.co*.uk*> >To: Tech Diver <techdiver@aquanaut.com> >Subject: RE: OMS wings problems >Date: Fri, 20 Mar 1998 11:48:27 +0900 >-Priority: 3 >MIME-Version: 1.0 >X-Mailer: Internet Mail Service (5.0.1458.49) >Content-Type: text/plain > >I have recently had the opportunity to take some fairly old BCDs apart >(3 of them). These were all, I would guess, in the region of 20 years >old. One of them had a bladder failure where the plastic seal holding >the inflator hose had disintegrated. The other 2 bladders had all the >attachments held by screw fittings (i.e. one piece inside the bag, one >outside) and were serviceable. The actual plastic used for the >construction for all 3 bladders was sound. Of course, I have no detailed >history of any of these units and can't tell whether they have had >thousands of dives on them, or have been stored for 15 years. > >I have only personally had one problem with BCDs, again the inflator >hose (blocked filter). It was only because I didn't address the problem >as soon as I noticed the decrease in performance that this was an issue >(I only put air in it at the surface, anyway, so was able to orally >inflate it when it failed completely). Heating the filter to red hot >with a gas flame, and then brushing out the ash solved the problem. > >JT > -- John Taylor, Marketing and Trading Systems, IT Development Credit Suisse Financial Products (Hong Kong) Ltd, 13F, Tower 3, Exchange Square, Central, Hong Kong Office: +852 2101 6927, Fax: +852 2101 7778, Mobile: +852 9031 6395, email: john.taylor@cs*.co*.uk* > -----Original Message----- > From: Jim Cobb [SMTP:cobber@ci*.co*] > Sent: Thursday, March 19, 1998 9:59 PM > To: Conrad Daubanton; Tech Diver > Subject: Re: OMS wings problems > > Conrad. > > I have personally never seen any BC fail. I have seen a couple of LP > inflator hoses fail, invariably right as the tank valve is opened. I > have > heard of inflator valves sticking open, the couple I have heard were > on > rental gear or they were frozen (ice diving). I heard one story of the > > inflator hose popping off the BC.In other words they were maintenance > issues. > > I might mention that I have seen BC's so worn and ratty, it is a > miracle > that they held air at all, but they did. > > Lets face it, a BC is not rocket science. When you look at your gear > overall I think that the weakest link you will see is the operator, > and > why make that situation worse by presenting multiple inflators/hoses > and > other issues into the mix? > > Jim > > Sender: Conrad Daubanton Date: 3/18/98 2:00 PM > > >Jim, Chuck: > > > >Does anyone know which part of a Wings/BC unit tends to fail more > often? > > > >Can anyone provide statistics? (Perhaps some shop owner that has > seen > >just about everything). > > > >Then we would know what kind of thing to prepare for. > > > >I've had no recent problems with the gear, but many years ago my > first > >BC (Horse-collar) had bladder problems, and having changed the > bladder, > >it developped overpressure/dump valve problems. Tired of repairing > it, > > I just bought another (stronger) horse-collar BC. This one also > >required a bladder change, but is now perfectly operational, though I > > >no longer use it now. With a Jacket type BC which I seldom use now, > >and with Wings which is what I use most, I've yet to have problems, > >they have never needed any repairs. > > > >Either gear is stronger now, or I give it less abuse than before. > > > >Conrad Daubanton > > > ------------------------------------------------------------------- > Learn About Trimix at http://www.cisatlantic.com/trimix/trimix.html > > > -- > 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'.
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]