Question: How much lift

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M

mgersch@cox.net

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After a few months of reading posts on scuba board, I have been won over to the idea of a backplate and wings (especially since I am interesting in learning about cave diving)

My question is:
How much lift do I need?
I see wings with 45 lbs to over 100lbs of lift.

I know that you are never supposed to use your BC as a lift bag so why in the world would you need 100 lbs of lift??

{When I dive with a full 7mm 2 peice suit I need 24 lbs to sink (with a single aluminum 80). I assume I will need less weight when I have a stainless backplate and steel doubles.} - (I don't know if this information will be necessary for you but just in case you need it)

Confused,
-Mike
 
mgersch@cox.net:
After a few months of reading posts on scuba board, I have been won over to the idea of a backplate and wings (especially since I am interesting in learning about cave diving)

My question is:
How much lift do I need?
I see wings with 45 lbs to over 100lbs of lift.

I know that you are never supposed to use your BC as a lift bag so why in the world would you need 100 lbs of lift??

{When I dive with a full 7mm 2 peice suit I need 24 lbs to sink (with a single aluminum 80). I assume I will need less weight when I have a stainless backplate and stainless doubles.} - (I don't know if this information will be necessary for you but just in case you need it)

Confused,
-Mike
Click to expand...

I don't think you'll ever have stainless doubles...

A 30 to 36lb wing is quite common for single tanks, while 40 for light doubles and 55-60lb for heavy doubles works well. There are many variables that have covered in many posts here in the past.

And, no, you don't need a 100lb wing unless its attached to an airplane.

MD
 
There is a ton of info in the archives, but to try a give you a quick answer.....

If your going to stay diving singles, a wing with 25-40lbs will be more than adequate, even if you get to the big tanks like the 130's and such....

If your going to doubles, you'll want a wing in the 45-55 lb range. That will be more than enough lift for doubles and stages. If going to doubles, you'll want to pick another type of floatation device such as drysuit and/or liftbag. You should probably have both if your doing doubles anyways.

IMHO, avoid double bladders and bungies. I don't feel like getting in a war at the moment, so I'll leave it at that.

hope that helped

SS
 
mgersch@cox.net:
After a few months of reading posts on scuba board, I have been won over to the idea of a backplate and wings (especially since I am interesting in learning about cave diving)

My question is:
How much lift do I need?
I see wings with 45 lbs to over 100lbs of lift.

I know that you are never supposed to use your BC as a lift bag so why in the world would you need 100 lbs of lift??

{When I dive with a full 7mm 2 peice suit I need 24 lbs to sink (with a single aluminum 80). I assume I will need less weight when I have a stainless backplate and stainless doubles.} - (I don't know if this information will be necessary for you but just in case you need it)

Confused,
-Mike
Click to expand...



Mike,

I'm making the following assumptions:

Your diving wet, and you can acheive neutral buoyancy at the surface with no air in your wing.

Wing selection involves (at least) two seperate questions.

Shape and lift.

Shape is pretty application specific. A narrow wing that works well for single tanks will be trapped under doubles. A wider wing designed for doubles will "taco" or wrap a single tank.

Wings designed for both single tanks and double tanks do neither well..

Second question is necessary lift. Your wing needs to be able to float your rig at the surface without you in it. Kinda nice not to have your rig disappear if you ditch it at the surface. Just add up the "in water" weights of your rig, i.e SSBP ~ 6lbs + tank + regs....etc. You can get the full and empty buoyancy of various tanks from the tank manufacture's websites. For a single tank BP/W usually less than 20lbs, often much less.

The other thing your wing or "Buoyancy Compensator needs to do is compensate for the buoyancy your exposure suit looses.

You wetsuit provides maximum buoyancy at the surface, and zero at about 165fsw. Your wing needs to be able to offset this value. Even very large very thick wetsuits typically provide no more than 25-30lbs of buoyancy, usually much less.

Who needs a 100lbs wing? Good question!



Regards,




Tobin
 
well, to start of with, measure the inherent bouyacy of your BC ( ie how much weight you need to sink your bc when empty and w/o air), and then take 24lb minus approx 8lb for the BP and STA and maybe 2lb for your regulator set and that should be approx how much weight you will need for a start.
That is how I did with my Ranger. I need about 18lb to sink with a 3mm full, and since switch to a BP/wing and with a 2mm shorty, i do not need any weight at all. Have yet to try with the 3mm full yet.
Hope this helps
 
Hey, Mech,
Get the wax out of your ears you old goat !!!
He said "stainless backplate and steel doubles"

. . . just had to snipe at ya !!!
 
The Kracken:
Hey, Mech,
Get the wax out of your ears you old goat !!!
He said "stainless backplate and steel doubles"

. . . just had to snipe at ya !!!
Click to expand...

Hey! I ain't old!!
I must have been too busy adding undivers to my ignore list over that idiotic 100lb wing thread ;)

MD
 
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