Quite a few deep divers in the ocean that will do depths,and bottom times that require a couple stages,and 3 deco bottles. Sometimes we tend to think fresh water and caves when we answer questions,which I don't doubt you have good bouyancy and trim,and where I am not an ocean diver to the extent I used to be, but it may be good to preface the answer with conditons that are being dove. So where I don't doubt,"4 stages, 3 deco bottles, and 2 scooters without need for a great big wing. 55-60lb works perfect." probably works great in one environment,it could be less than optimal in another. Since BP/W is slowly becoming a lost art in favor of sidemount,this information is good,because "what comes around,goes around".
BP&W question for doubles divers
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Quite a few deep divers in the ocean that will do depths,and bottom times that require a couple stages,and 3 deco bottles. Sometimes we tend to think fresh water and caves when we answer questions,which I don't doubt you have good bouyancy and trim,and where I am not an ocean diver to the extent I used to be, but it may be good to preface the answer with conditons that are being dove. So where I don't doubt,"4 stages, 3 deco bottles, and 2 scooters without need for a great big wing. 55-60lb works perfect." probably works great in one environment,it could be less than optimal in another. Since BP/W is slowly becoming a lost art in favor of sidemount,this information is good,because "what comes around,goes around".
LiteHedded
Contributor
a 7 bottle dive in a wetsuit is just academic. you'd be hypothermic before your 20' gas switch
PfcAJ
Contributor
Kelly. Listen. The gear is NEUTRAL. There is nothing to "lift" with a big wing. On a dive where you need 3 deco gases, the stages are downright positive. Scooters should never be negative, especially in the ocean. The only items that might be negative are the shallow deco gases, and it's already been well established that they aren't heavy enough to require a big wing.
I think you're either a) trying argue for the sake of argument or b) are not versed in how to set up gear for an efficient deep dive. I'm leaning toward a, but some of the stuff you're saying doesn't make sense.
I think you're either a) trying argue for the sake of argument or b) are not versed in how to set up gear for an efficient deep dive. I'm leaning toward a, but some of the stuff you're saying doesn't make sense.
DaleC
Contributor
Clarify please.
If I have stages (say 80's), backgas doubles, and some deco bottles; won't I be negative the amount of gas I will expend during the dive? Sure I could calculate to be neutral or positive at the end but at the beginning I need to compensate for that weight. I could see the worst moment being a boat jump with a wing failure when one is heaviest.
I'm not saying one needs a big wing but there is some need at some point for lift.
If I have stages (say 80's), backgas doubles, and some deco bottles; won't I be negative the amount of gas I will expend during the dive? Sure I could calculate to be neutral or positive at the end but at the beginning I need to compensate for that weight. I could see the worst moment being a boat jump with a wing failure when one is heaviest.
I'm not saying one needs a big wing but there is some need at some point for lift.
I have to agree with PfcAJ, regardless of environment the gear is essentially neutral to a few lbs neg, the gas is the weight and if it's trimix + deco even then only a few neg. The wing essentially is there for the surface at the beginning of the dive and to compensate for the gas during the dive.
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PfcAJ
Contributor
On a dive where you need 3 deco gases, there is enough helium in the stages so that they float.
While I think you'd be hard pressed to find an ocean diver using 4 stages (bottom gas), but a reasonable dive would be 1 stage and 3 deco gases. That's a sub 240 dive, hence all the helium. A 35/25 bottle is
neutral, so the heaviest things you've got are the 50% and oxygen, each about 3 or 4 lbs negative. Backgas is light, too from all the helium.
The argument that having a bunch of stages requires a big wing just doesn't make sense when you look at the specifics. Of course, use steel bottles and fill everything with air and you've got a different situation, but I would never sign up for that in a million years.
Ive done one a fair share of multi stage dives with nitrox and it sucks. Nitrox is heavy and you must compensate with a full wing which really slows you down and impacts buoyancy control. When I do those dives now I lighten the load with helium. Much faster, much easier to manage in water, plus a narcosis advantage.
Dr. Lecter
Contributor
PfcAJ
Contributor
I mean, if you wanna be narced on a 250+ dive and strap on a massive wing to float the bricks you're diving with, go bananas.
Tell us us how you do it, Doc. When was the last time you did a big OC dive and carried a bunch of gear?
Tell us us how you do it, Doc. When was the last time you did a big OC dive and carried a bunch of gear?
LiteHedded
Contributor
having actually done a few 7+ bottle, two scooter dives sub 200+ feet I know a thing or two about how to pull it off.
sure if you want to invent imaginary nitrox versions of the dives you might need some more lift. but that dive presents more problems that what wing to bring with you. it's obviously not worth considering.
Dr. Lecter
Contributor
Before I went to CCR, a pretty standard 270' dive with 30+ minutes of BT was double steel 100s or 130s depending on BT, with 15/30 backgas, 21 or 32 travel/deep deco, 50 mid deco, and 80 or 100 shallow deco. Despite being wet, often not even in a wetsuit, these dives still didn't need more than a 40 (100s) or 55 (130s) lb wing.
For 2-3 hour CCR dives down to 300', using a scooter the whole time, I'm happy with a 7mm merino lined suit...lots of bailout, still no giant wing. Anything longer than 3 hours with a scooter and I start to seriously consider the drysuit.
Then again, I'm not hauling gas for a buddy and I don't need extra wing lift to assist a heavily-geared buddy with their own wing failure. YMMV.
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