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At 08:28 AM 12/5/99 -0700, Shimell, David (shimell) wrote: >>So if Jack (the nipper) or his buddies ever need to drop >>the belt during self rescue or helping out someone else, I >>feel happier that it can be done quickly, easily and in a >>single movement. > >The best way IMHO is under the crotch strap, but I understand your points >about a newbie being more easily stressed and making the wrong decisions, >specifically forgetting to drop the weight belt. We see many sad cases of >drowning with newbies who panic and are found on the bottom with weight belt >still attached. > >My view is that if they forget to drop a weight belt when using a >conventional BC, then whether it is under or over the crotch strap makes no >difference at all. If we are considering an inexperienced diver who >accidentally loses a weight belt, there is the possibility that in panic they >will hold their breath on the ascent. This act is likely to produce severe >lung damage, whereas any bend would have most likely been curable. With respect, I think you're allowing for the wrong problem. They're not so inexperienced that a breathhold ascent and embolism is likely. However, loss of primary bouyancy can happen to anyone - hoses pull out, inflators fail. Then, the jetissonable wightbelt is the ONLY bouyancy device. It should not be compromised. And a lot of problems happen on or near the surface. In my mind, I'm running through the struggle I'd have to clear a weightbelt that I've dropped which is then caught inside my crotch strap and holding me under. It's hanging between my legs with half the weights on each side. I have to lift the whole weightbelt up and pull it up and away clear of the crotch strap, hoping the weights don't catch on the webbing, or I'm in deeper shit. Or I have to undo the waist strap of my harness and slide the crotch strap off it - against the weight of the hanging weight-belt, hoping the loop doesn't catch on the buckle on the way off. Only then can I let the weightbelt fall away. And the ONLY reason I dropped the belt in the first place was because I desperately wanted to take a fucking breath! (excuse the language, I got a bit wound up thinking about it). Thus, in >the case of a newbie, the ramifications of accidentally dropping a weight >belt is not of a bend but of lung damage which can occur at the depths to >which a newbie would be diving i.e. it can happen in a swimming pool. As >the diver progresses in experience and depth, lung damage should be less >likely but a bend more likely. An experienced diver should be able to cope >with removing the crotch strap to drop the weight belt but can do nothing >much to deal with a weight belt which has already been dropped by accident. >So avoiding the problem in the first place is the best action, i.e. retain >the weight belt under the crotch strap. I think the idea of using a weightbelt is to be able to drop it, not to have it trapped on oneself. IF accidentally dropping the weight belt was the REAL problem, why not just do away with the quick release. > >>When they start to dive deeper or get into longer exposures, >>still no-deco stuff, but where a quick trip to the surface >>might have consequences, I'll introduce the alternate air >>source. I'm thinking about a 3 litre pony slung from the >>front - sort of early stage-training. What d'you think? > >I read this paragraph several ways, so please excuse me if I am inferring >incorrectly. > >Inference 1: if you are saying that to deal with the case of a dropped >weight belt, you are going to provide an alternative air source, this does >not make sense. Deal with the cause, not the symptom. I'm sure you don't >really mean this. Nope. I don't mean that. The accidentally dropped weightbelt problem should be prevented by using a good stainless steel buckle, allowing an adequate tail of webbing to run through it, and closing it firmly. Not by using the crotchstrap to tie the belt to the diver. > >Inference 2: if you are saying that if some problem occurs, you will provide >an alternate air source to allow the diver to sort the problem, then this is >common sense and what we all do. However, I can't see how this has any >bearing on how a weight belt is carried. In fact, having a alternate air >source furthers the argument of carrying the weight belt under the crotch >strap. It takes longer to drop the weight belt when under the crotch strap. >The alternate air source provides additional time over that available from >the primary air source. These guys are capable of free ascents from 15 - 20, maybe 25 metres. But 30 metres? 35 metres? I would like to think they understand the importance of tight team diving. But they're kids and kids get distracted. Ascent could still be a necessity. There's nothing hard and fast here. But when these guys start doing deeper dives, 30-40 metres, where a free ascent to the surface starts to assume more risk, or when they're doing dives close to Dr Buhlmann's NDLs, then I think I'll encourage them to clip a small sling cylinder off on the front as a back up air source. Of course on the left side. > >Moving on to your possibly-not-so-related issue of carrying a pony, I >presume you mean having it stage mounted on the left. I prefer to think of >ponies as small stage bottles. This is for two reasons: > >1. If you carry one, you rig it the same way as a stage. >2. The gas capacity of the stage must be appropriate to the dive being >undertaken. > >Note that I have not entered the debate on single plus stage vs. Doubles. I >occasionally dive with a 3 litre stage but carry oxygen in it for deco and I >dive doubles. I don't own a 3 litre cylinder so don't dive this arrangement >very often besides, my deco is requires more gas than is available in a 3 >litre stage. However, I don't see how a stage is relevant to your point? It's not. I went and introduced a new topic. How are the mine dives going? rgrds billyw -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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