Dual bladder BCD 60 or 94 lb lift which one ?

OK guys here goes I need your input

I am buying a new OMS Dual bladder BCD 60 or 94 lb lift

The question is why wouldn't you go with the 94 just in case you needed it. I've been told that it has no performance effect between the two systems they both perform the same way with the bungee's.

and yes sometimes I use a dry suite and some times I don't , I want the system to be redundant no mater what dive configuration I am gearing up for.

Currently I use 2 119 steal tanks.



BC118-K 94lb Double Bladder 36.5"w x 25"h 6.33 lbs 94 lb lift 1000 Denier Nylon with 5-6oz Pu backing 210 Denier Nylon w/3.8oz PU backing

BC115-K 60lb Double Bladder 29"w x 25"h 6.32 lbs 60 lb lift 1000 Denier Nylon with 5-6oz Pu backing 210 Denier Nylon w/3.8oz PU backing

I think you got really good advice in your other thread, but here goes.

If you don't need 90 lbs (and very very few people actually do) you shouldn't buy it because it has a higher potential for trapping air and "pancaking" around your tank. As such it's harder to vent when you need to and carries a slightly higher potential for causing a runaway ascent. Similarly, if you're one of those people who believe drag is a big deal while diving, the extra material will be higher drag in the water. The extra material will also have some sort of (likely positive) buoyancy that you will have to add weight to counteract. Even if it's just a few ounces, it adds up. On land the extra material will also weigh more so you'll actually have the added weight of the material and the extra lead to counteract its buoyancy that you have to carry to the dive.

As for dual bladder, yeah it would be nice in an overhead environment but I wouldn't bother for standard open water rec diving. YMMV. Again, it's extra crap but it is a semi-convenient source of redundancy.

Even 60 pounds is a relatively large wing. I only dive single AL80s but I'm using an old horse collar converted to a wing on a steel plate and it has between 15-18 pounds of lift based on my tests. It's more than enough for me, even in cold water. Even with doubles (AL80s) I would only need about 24 pounds of lift and probably 35 pounds if I switch to steel 100s. I'd recommend looking at this thread for a very good calculator for lift and discussions around such:
http://www.scubaboard.com/forums/bu...ems/158370-ultimate-wing-lift-calculator.html

Nice Thanks for the Tool

I use a 94# OMS dual bladder BWOD. It's a nice wing for OW deep diving; the most stable doubles wing I dive and I have Halcyon 40# Evolve & OMS 45# Larry Green wings too (for overhead)

Having said that, 94# is more lift than most divers will ever need. More than you need isn't better

fjpatrum:

...you shouldn't buy it because it has a higher potential for trapping air and "pancaking" around your tank. As such it's harder to vent when you need to ...if you're one of those people who believe drag is a big deal while diving, the extra material will be higher drag in the water. The extra material will also have some sort of (likely positive) buoyancy that you will have to add weight to counteract. Even if it's just a few ounces, it adds up. On land the extra material will also weigh more so you'll actually have the added weight of the material and the extra lead to counteract its buoyancy that you have to carry to the dive

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Honestly, most of this is crap

fjpatrum:

Even with doubles (AL80s) I would only need about 24 pounds of lift and probably 35 pounds if I switch to steel 100s.

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Who makes a 24# doubles wing? Or 35# for that matter?

michaelallen1978:

I've been told that it has no performance effect between the two systems they both perform the same way with the bungee's.

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Do you believe that you can add 50% capacity to anything (diving equipment or otherwise) with no other effects?

Have you, or other people in this thread offering their advice, dived either one?

Tortuga68:

Have you, or other people in this thread offering their advice, dived either one?

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Nope, nor am I offering advice; just asking questions about something that smells funny.

Incidentally, how do dual bladder wings work? Does a 90# wing consist of two 45# bladders, or are the primary and redundant bladder each capable of 90#?

good Q's

Tortuga68:

I use a 94# OMS dual bladder BWOD. It's a nice wing for OW deep diving; the most stable doubles wing I dive and I have Halcyon 40# Evolve & OMS 45# Larry Green wings too (for overhead)

Having said that, 94# is more lift than most divers will ever need. More than you need isn't better




Honestly, most of this is crap




Who makes a 24# doubles wing? Or 35# for that matter?

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I don't know of anyone who makes a 24# doubles wing. I think I might have seen a 35# wing that supposedly is capable (arguably) of doubles, but I'm not 100% sure about that. My point wasn't that I could find what would be a "best fit" for me but a 40# wing is a hell of a lot closer than 90#. I don't dive doubles and have no plans to in the future, it's just an example of what I would "need" if I did, versus the options the OP gave as his/her choices.

As for the stuff that is "just crap" I don't necessarily believe much of it will have any real affect at all. It isn't entirely negligible, though. It isn't something I would personally give one rat's ass about, but it's still something others might consider when deciding what's important in the wing they're going to buy. I don't believe wing drag is any kind of significant factor for people who are regular divers, but the material does have a weight and natural buoyancy that can probably be ignored but will have some non-zero effect. The taco/pancake effect is probably the most likely situation in that regard. I think, for me, the air trapping is the biggest concern, as someone who has absolutely no direct experience with large wings.

All of that is kinda 'whatever' in my book. The only major hangup is the auto-deflate 'feature' of the bungee.

If you tear a wing, hydrostatic pressure will force air up and out, but you can position yourself such that it has no path to do so. This is sometimes demonstrated in tech courses by the instructor removing a student's rear dump.

A wing with shock cord constraining its shape will in theory dump until the bungees are no longer loaded regardless of orientation.

I've never seen it happen, but I believe some on the board have, and that failure mode is source of the acronym Tortuga used to describe his OMS.

In selecting wings, I have to ask myself a question: on a dive where I need so much lift that the wing needs to be mechanically constrained, how much of it can I afford to lose in a failure? If I were doing something with so much exposure (depth and time) that I need to offset close to 70+ pounds of gas weight, is there a better solution (offloading cylinders to support members, closed circuit, etc.)?