Tobin, the only misinformation I've seen in this thread has come from you. You contradict yourself in the same post and you try to twist what I've said into what you wanted me to say. Sorry but it doesn't work.
cool_hardware52:
Ah so we agree that a BP&W is the preferred means of mounting doubles. Good, common ground.
Another attempt at twisting my words. We agree it's the most common. We agree it's the method you prefer.
cool_hardware52:
Are you now suggesting that this large majority of backplate wearing doubles divers have been duped? That they would be better off using jacket BC's with their 2 x 130's?
I'm suggesting many folks have no idea there is an option. I'm now suggesting you are playing fast and loose with the truth by implying the large majority of backplate wearing doubles divers dive with twin 130s. We both know that while there are some, most are using smaller tanks.
cool_hardware52:
So the standard against which all things diving is to be measured is whether or not Walter himself has seen it happen? If Walter has not experienced something it does not exist. Ok, got it. Guess all those "Hog" harnesses with crotch straps are just being used by the legions of DDD's, "Duped Doubles Divers"
Substitute "Tobin" for "Walter" in the above quote and we'll have your standard. As for me, I know others don't necessarily agree with my opinions and accept that. I know other folks like rear dumps, so I mention them instead of being close minded and suggesting if I don't use it, it's junk. Furthermore, I have no vested interest in selling any type of gear. Do you have that same lack of interest when you suggest a BP/wing?
cool_hardware52:
If multiple dumps are not necessary why do you rate BC's that have them higher than those that do not? They add little or nothing of value, but do increase the cost and potential failure points.
Tell me please Tobin, is there a BC on the market with only a single dump? You advocate multiple dumps here:
cool_hardware52:
Good technique will allow venting with only two, the Oral inflate, and the rear OPV or Rear Dump.
For myself, I only need one, I like having that second dump, but I don't need it. I realize some folks, like you, also like having that rear dump, so I mention it as well.
cool_hardware52:
That's exactly what I said in my first post.
No, you didn't. In your first post, you said:
cool_hardware52:
Almost all wings have the fill hose at or very near the "top" of the wing. The fill hose is a means to vent the wing. Festooning a bc with multiple dump valves is the classic example of adding gear to compensate for poor technique. It adds cost, failure points and conditions the diver to reach every where when they need to vent gas.
All BC's need at least one OPV (over pressure valve, aka rear dump) and a fill hose / power inflator. More than that is decoration, IMO.
You did not say:
Walter:
Actually, good technique will allow venting with only one.
cool_hardware52:
What exactly is nice about a "feature" that is unnecessary, and adds potential failure points?
Depends on exactly which feature. For example, a BC is unnecessary and adds potential failure points. What's nice about using a BC? Yes, a dump valve can fail. Yes, they have failed. I've seen them fail. Are you so over weighted you can't swim your rig up? You shouldn't be. If the dive plan call for a rig that is that heavy, you should also plan for a backup lift system such as a dry suit or lift bag.
cool_hardware52:
If a shoulder mounted OPV fails how do you trap gas in the BC?
I wouldn't. I would abort the dive by swimming to safety stop depth, staying there for 5 minutes and then exit the water.
cool_hardware52:
Quite true, and not at issue here.
Do you know you agreed that while the rear dump is a over pressure relief valve, an over pressure relieve valve is not necessarily a rear dump?
cool_hardware52:
Previously you made the claim that the OPV was not known as a "Rear Dump"
Yes, I did and you just agreed with me on that point.
cool_hardware52:
The fact remains that the term "rear dump" enjoys wide, popular usage when referring to wings.
That's not at issue and it is not confined to BP/wings, but used with other BCs as well.
cool_hardware52:
(Wings BTW, are a type of BC)
Yes, I'm quite aware of it and have often corrected folks when they've said otherwise. What's your point?
cool_hardware52:
This link clearly refers to the OPV as a "dumpvalve" and it is clearly located at the bottom, or "rear" of the wing.
Yes, but that's not in dispute, only your assertion that all over pressure relief valves are rear dumps.
cool_hardware52:
I won't presume to speak for Peter, but I'd guess that he never considered mounting a OPV on the right shoulder of a wing.
Very good, now please stop trying to speak for me. It doesn't matter if he's ever considered it or not. Others have mounted them on the right shoulder and other locations as well.
cool_hardware52:
Trust me, if I could avoid interacting with Walter I would. I count to ten before I respond to any of Walter's posts.
After counting to ten, reread what I've posted, you seem to miss what I've said quite often. After you've written your reply, you should read it over. You might not contradict yourself as often.
cool_hardware52:
I will not however let what I consider to be mis information being offered to an admitted newbie.
Then stop doing it.
cool_hardware52:
What I object to is personal opinion being presented as fact.
I have not done so. I gave facts about BCs, then explained why I believe certain features are good or bad. If you can't understand that all posts about value are purely opinion, that's your problem. For example:
Walter:
No padding - Padding requires additional weight, yet compresses at depth so it no longer cushions. Additionally, air in a BC lifts the BCs weight off your back rendering padding redundant. Padding also increases drag, making dives in current more difficult and increasing your air consumption.
You agreed when you posted your opinion:
cool_hardware52:
very true. Padding, and padded cummerbunds add needless buoyancy
We agree on this point, but it's simply our opinions. Were you posting your opinion as fact? Is that OK for you, but a sin for others? Or were you expecting folks to be able to see that your statement was obviously your opinion? You should be aware that other divers disagree with us. Most divers do not see padding as needless buoyancy. That padding adds buoyancy is a fact. That padding compresses at depth is fact. That air in the BC lifts the BCs weight off your back is a fact. That the additional buoyancy is needless is opinion. That padding is something to avoid in a BC is opinion.
cool_hardware52:
I have never said that it was impossible to use doubles with anything but a BP&W.
It's hard to say, you seemed to say it was impossible, but contradicted yourself in the next sentence of post #8. See below:
Walter:
You can only use doubles with a BP/wing (you can wear doubles with any BC as long as the BC has enough lift).
cool_hardware52:
You disagree that it can be done, implying it's impossible.
cool_hardware52:
While it may be possible to use doubles with some jackets it is very seldom done.
Now you contradict yourself by saying it is possible and then change the subject by saying it is very seldom done, something that was not at issue.
cool_hardware52:
Walter claims that the wide spread use of BP&W's is a direct result of some myth.
I never said that. First, the use of BP/wings is not all that widespread when compared to other BCs in use. Next, I never claimed that use of BP/wings is due to myth. I merely stated that it is a myth that it is impossible to dive doubles without a BP/wing. When I said, "Such a survey won't reveal just a majority, but a vast majority, due to a large degree to the myth that a BP/wing is the only possible way to dive doubles." I did overstate the case a bit. You have my sincere apology. I was wrong to state it in that manner. We'll never know how much the myth has affected BC choice in diving twins.
cool_hardware52:
Try not to loose sight of the purpose of this thread.
You seem to have lost sight of that in post #8 when you got me in your sights.
cool_hardware52:
How long do you wish to beat this dead horse? I have already agreed with Walter that not every OPV is in fact a "rear dump" in this exchange.
You did, but then you started beating that horse again when you contradicted yourself on that point.
cool_hardware52:
That still does not invalidate my reference to an OPV as a rear dump.
Actually, it does. A rear dump is an over pressure relief valve, but an over pressure relief valve is not necessarily a rear dump. I know you already agreed, but then you disagreed, then you agreed, now you're disagreeing again. Do you even know what you think on this topic?
cool_hardware52:
These terms are used interchangeably with regard to wings.
If referring to a specific BC that only has two dumps, one being the inflator hose and the other being the rear dump, that would be correct, but only in that specific situation.
cool_hardware52:
Believe or not some people don't know what "OPV" means, but they do know what dump valve is.
I believe it.
cool_hardware52:
Remember I talk to divers much like the OP in this thread every day. It's what I do for a living.
That is a frightening thought.