BCDs Vs. Current

[AbyssalPlains]

I'm a newcomer, and while I appreciate that an oversized wing will "taco" and you may have trouble exhausting its air, I could use some help understanding why it might be "too much lift." My novice brain thinks that you only inflate it enough for your needs, and you will not put any more air into a 65lb capacity wing than a 45lb or 30 lb capacity wing, or any sized jacket BCD.

What am I missing with respect to how much lift you will actually use?

You're not missing anything, you got the point exactly. The difference is like going grocery shopping with a nice little canvas bag that accommodates your goods nicely and using a tarp instead, shoving a loaf of bread and perhaps some apples inside. THe result? The "unused" tarp fabric is flapping all over the place, creating drag and becoming unwieldy.

By the way, what is up with these flaming chicks????

 

[RonFrank]

65lbs wing on a Single? I don't even know why they make such a wing.

I'm betting I've never filled my 30lbs wing with a single even half way, AND I wear weight. IOW's if I use a SS 120, I'd just drop weight, and still have plenty of lift. This is diving a SS backplate and STA (12 lbs) in a drysuit with another 10lbs of weight, so I have some weight to trade-out, and the 30lbs lift is still more than I really need.

When I do doubles, I use a buddies 40 lbs wing, and that is plenty.

Even if my buddies wing completely fails, most I dive with on the regular can swim it up. My helping by adding some air and holding on to them even in doubles is NOT going to require me to fill the BC.

Big wings have all the issues that others have described. There was a noticeable difference especially for trapped air situations when I sold my Ranger, and went to a Stiletto, and a BP/W with a 30lbs wing for singles. All wings can trap air, but big wings are MUCH more prone to do so, it's just in their nature!

If you can exchange this BC, I would. I'd go with a good solid singles wing, or Zeagle Stiletto travel size Back Inflate BC. If you want to go tech, than get a BP/W, but a nice travel Back Inflate is also a good alternative. I don't travel with my wing even if I do know a lot of divers who do.

EVERY tech diver I have ever known has a closet full of wings/BP's/STA's and various junk. Do not confuse streamlined or tech with a lack of redundant diving rigs, and rigs for various types of diving. If that is the route you go, that is likely where you will end up. So the whole buy once stuff is crap in the sense I NEVER see those type of divers with just ONE setup.

I like my Stiletto for travel. It packs well, has pockets, dives well, and really does not provide any less benefit for me vs. my BP. For cold water dry diving I like the BP/W much better as it distributes the weight better, and takes a lot off the belt.

 

[BKP]

65lb of lift is an obscene amount even diving a twinset with stages.
Rough ball park figures, a single should have about 30lb and twinset with stage 40lb.

I was right with you, until the "twinset with stage 40lb."

I agree with all your points, and with a standard al80 (even steel 100) single, the OP should be able to swim his rig up from almost any recreational depth, with a deflated wing.

I use a 30lb. with my steel 100s (singles), and can't remember ever having the wing more than 30-40% inflated, even at 120ft. fw, at 58 farenheit (in a 5mm). The *only* time I fully inflate is once I'm surfaced.

With steel doubles, and perhaps a deco bottle, however, which will get you largely negative from the get-go, and further compression of your neoprene (assuming diving wet), I'd want more than a 40lbs. at significant depth (which is the assumption for the doubles and deco).

I agree with you however... a 30lb Mach V, or even 26lb. Torus is more than enough for singles. (IMHO).

 

[Spork]

I dive steel doubles but not yet deco. I have an Agir 38lbs wing and it's more than enough. Even with a deco and a stage this wing will be able to generate enough lift. If the wing fails, it will not make a different if the lift is 30lbs or 65lbs, if it fails you will have no lift either way. In this case you redundancy, something we haven't discussed in this thread.

When travelling to warmer waters I use a small US divers Halcyon (I reccon it's about 18-20lbs lift) and before I got doubles and drysuit I used this here in cold sweden with a 7mm semidry and a single 10liter 300 bar steal tank that's quite heavy. 65lbs is in any case way too much and will cause more problems than it will ever be able to solve.

 

[String]

With steel doubles, and perhaps a deco bottle, however, which will get you largely negative from the get-go, and further compression of your neoprene (assuming diving wet), I'd want more than a 40lbs. at significant depth (which is the assumption for the doubles and deco).

No issue here with twin 12l tanks (steel) and 2 x 7l stages (steel) on a 40lb wing.

Having said that there isnt a chance id ever do a long deco dive wet due to cold (even in so called warm water).

 

[Walter]

humans are about as hydrodynamic as a brick anyway.

All the more reason not to make it any worse than necessary. There is a big difference in effort from one rig to another.

 

[Nick_W]

All the more reason not to make it any worse than necessary. There is a big difference in effort from one rig to another.

I'm not saying he needs 65 pounds of lift, there are plenty of valid reasons why he probably doesn't want that. Drag is not one of those reasons. I'll see if I can find the report I found last time that shows that the difference from one rig to the next is almost nothing.

 

[Blackwood]

Why would that diver be diving about 50lbs over weighted?

You weight yourself to overcome the suit buoyancy and gas lost during the dive. Typical size single tank you're going to use about 3kg (7lb) of gas assuming he was weighted correctly.

So where exactly is the other 55lbs going to be needed?

Unless you have a buddy who was diving about 30lb overweighted who lost their buoyancy AND managed to cable-tie themselves to a nearby rock i cant see the need.

Not everyone dives properly weighted, especially new divers who are more likely than others to run into problems.

We do a lot of things to account for extremely rare emergencies. One such emergency may be an overweighted drysuit diver going to 130 feet on a HP130 + hardmount pony who has a fast leak at his first stage (that he doesn't notice during descent because he's in someone else's bubble stream) which drains him so much that he can't slow his descent and he hits the bottom hard enough to knock him out. Likely? No. But then again neither is a catastrophic loss of gas at depth, and many of us account for that.

Now, I'm not saying 65# is required. I wouldn't dive 65# even in steel doubles with stages. What I am saying is that what many divers use may not be enough in the rare event of an underwater rescue that involves surfacing someone else.

 

[String]

Not everyone dives properly weighted, especially new divers who are more likely than others to run into problems.


Now, I'm not saying 65 is required. I don't dive 65# even in steel doubles with deco bottles. What I am saying is that what many divers use may not be enough.

Id venture that even in a 30lb or so you could account for that provided you are properly weighted yourself.

Yes many people dive overweighted but even then ive rarely seen 10lbs overweighted or if i do then dive with someone else.

30-35lb i still think should be more than enough and over 40 is ridiculous.

Diving heavy rigs without redundant buoyancy is a whole new issue as well (and no i dont believe a so called balanced rig is always possible).

 

[FIXXERVI6]

I've had so many people tell me that X doesn't affect drag and Y doesn't affect drag just because as humans we are not hydrodynamic as it is.

Gonna throw int the BS flag on this one.

The difference between a drysuit and wetsuit drag is EASILY felt

The difference between 8" tanks and 7" tanks can be felt (doubles)

The difference between your stage bottle hanging down a couple inches and up tight is majorly felt.

True 'nough we are not very slick creatures in the water, but we are not talking about wind drag, drag in the water is much much higher so every bit counts.

If you don't beleive me try it, especially swimming into hard current.

I've seen people dive single tanks on the zeagle tech, they loaded up with INSANE lead to keep the wing from tacoing around the tank AND made their own bondage wings by putting surgical tubing around the bladder in spots.

Wrong tool for the job in my opinion.