Question Shoulder vs butt dump
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Scared Silly
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Because the industry standard is to have the inflation hose on the left. That said, many BCD do not have a shoulder dump because pulling on the hose can put undo strain on the connection.
Note, double bladder BCD have a right shoulder inflation.
The left front and/or right front is for venting gas when one is horizontal.
hmm-maybe my question wasn't clear
first, for a right rear shoulder dump, you pull on the dump cord - not a hose; for rec/sport diving, essentially "all" bcd inflation hoses come over the left shoulder, and, to my knowledge, the hose is never "pulled" when dumping air so I'm a bit confused by that response;
my question was aimed at why isn't a right rear shoulder dump more common, ie, why don't more manufacturers think that it is a good, safe, functional idea since that the vast majority of the time, a diver is either vertical or prone, air rises, making it more easily dumped from a rear shoulder dump if/when necessary;
as opposed to the more common left lower front dump which, if vertical/prone, is pointing in the wrong direction; i guess its functionality would depend on how the air is stored in the bladder relative to the internal dump port in the bladder;
thanks for your comments
first, for a right rear shoulder dump, you pull on the dump cord - not a hose; for rec/sport diving, essentially "all" bcd inflation hoses come over the left shoulder, and, to my knowledge, the hose is never "pulled" when dumping air so I'm a bit confused by that response;
my question was aimed at why isn't a right rear shoulder dump more common, ie, why don't more manufacturers think that it is a good, safe, functional idea since that the vast majority of the time, a diver is either vertical or prone, air rises, making it more easily dumped from a rear shoulder dump if/when necessary;
as opposed to the more common left lower front dump which, if vertical/prone, is pointing in the wrong direction; i guess its functionality would depend on how the air is stored in the bladder relative to the internal dump port in the bladder;
thanks for your comments
The more experienced you are as a diver, the more you will use the left rear dump and not even think about the need for a right shoulder dump.
If you are diving in horizontal trim (as you should be) and need to let out a little air, you just reach back and give a little tug. If the only thing you have is a shoulder dump, you have to tilt yourself into an upright posture, dump the air, then return to the proper horizontal posture. Most experienced divers primarily use a shoulder dump to begin the descent from the surface. From then on it is mostly the rear dump.
If you are swimming in a 45° (or greater) angle like most beginners, then the shoulder dump is what you will use. That is not, however, advised.
If you are diving in horizontal trim (as you should be) and need to let out a little air, you just reach back and give a little tug. If the only thing you have is a shoulder dump, you have to tilt yourself into an upright posture, dump the air, then return to the proper horizontal posture. Most experienced divers primarily use a shoulder dump to begin the descent from the surface. From then on it is mostly the rear dump.
If you are swimming in a 45° (or greater) angle like most beginners, then the shoulder dump is what you will use. That is not, however, advised.
Pavao
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But it is common, very common, in fact I’d think there are very few modern recreational BCDs which doesn’t have a right shoulder dump valve.
If you’re referring to modular wings, then yes, not common, I can’t even think of one which does have a right shoulder dump valve, and if you find one, probably a good idea to stay clear.
Besides the reasons already mentioned above, it wouldn’t be very practical to have one in a modular system, which would require running the pull cord over the shoulder and securing it to the harness somehow.
I’d say though, in my observations, most recreational divers are more likely to pull on the inflator hose rather than the right shoulder dump, which is pretty dumb if ask me, pulling the inflator and putting strain on the elbow assembly when you can achieve the same task using the dedicated vent on the right. Yet another example of poor training and gear design, which remains extremely popular in the industry.
I have a monofilament cable that is connected through the low-pressure (corrugated) hose to a pull dump on my left shoulder. Since perfect trim for me is with my head a smidgen up, using the left shoulder pull dump works just fine! However, I rarely add or release gas once at depth on open circuit, preferring to use my breathing to fine tune my depth. I usually set it at the beginning of the dive and don't touch until I inflate on the surface. This is simple since I rarely dive a wetsuit. On a rebreather, I constantly have to adjust my depth using my bladder. Sticking with the one hose to either add or subtract makes it simple. But everyone dives a bit differently, so do what works for you.
One thing to bear in mind is that any problem with a pull-cord dump on the shoulder will completely deflate your BCD on the surface. On two separate occasions, I’ve had dive buddies with right-shoulder dump valves have the pull toggles get entangled underwater, which held the dump valves open so that they couldn’t inflate their BCD on the surface. Made for quite a stressful end to the dive, especially the one time it happened at night, after surfacing close to a lee shore with unexpectedly high winds.
This is obviously entirely anecdotal, and I’m sure there are lots of different stories about BCD failure that don’t involve shoulder dumps. But as other people have said, it’s entirely unnecessary (just use your inflator to dump if you’re vertical), and introduces a very real point of failure.
This is obviously entirely anecdotal, and I’m sure there are lots of different stories about BCD failure that don’t involve shoulder dumps. But as other people have said, it’s entirely unnecessary (just use your inflator to dump if you’re vertical), and introduces a very real point of failure.
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