Which wing

[Packhorse]

I have brought a second hand Transpac II BC with a dual bladder 45lb wing. While I belive this is suitable for doubles I think its a bit overkill for a 15L (123cf)faber single.

My old jacket BC has 15 Kgs (33lb) of lift, I used 7kgs (15lb) of lead. I dive with a 6.5 mm wetsuit in 13- 23 deg C water.

Now my understanding is you should have zero boyancy at the end of your dive, or slightly negitive to allow for a situation where you may use up ALL of your air. This should be achieved by adding or removing lead from your belt ( not a fan of intergrated weights) not by air in your BC.
So why should I have anything bigger than the smallest wing (18lb) since this will give me 18lb positive boyancy at the end of the dive and 18lb - weight of gas ( 6lbs ?)at the start?

2nd question. What exactly is a balanced reg? I know I can search but Im sure someone would just love to answer my question.

 

[RJP]

See the thread one or two below here for good info.

Long and short of it, the wing needs to provide lift to offset the weight of the plate and gear attached to it. So 18lbs of lift will NOT give you 18lbs of positive bouyancy if you have it attached to a 6lb plate and a tank that is 10lbs negative at the start of a dive.

The DiveRite Express site seems to recommend the Venture wing for use with the TransPac and single tanks, including 120cf tanks. From the website:

The Venture Wing is designed specifically for applications combining single cylinders with either the TransPac or TransPlate as well as a traditional backplate/harness configurations. The Venture wing's 30-pound capacity works with the largest of single aluminum or steel cylinders.

Ray

 

[Packhorse]

Sorry 2nd question shoulg be balances rig not reg.

 

[*Floater*]

Sorry 2nd question shoulg be balances rig not reg.

Diving a balanced rig is a good idea. It means being weighted so that with tanks almost empty you are still neutral close to the surface and can do your 3m (10 ft.) safety or deco stop without problem, and using tanks and other equipment which allow you to ditch excess weight if necessary and swim your rig to the surface at any point of the dive (namely when your tank or tanks are full and you are deep so that your wetsuit has compressed and lost most of it's buoyancy). For example, if you use a Heiser 190 (-62.3 lbs buoyant when full) then it's pretty much impossible to have a balanced rig because a normal person could not swim that up.

18 lbs wings are usually recommended for warm water diving to be used with an Al80 or similar tanks. From your describtion it seems that you would need more lift that that.

 

[Packhorse]

See the thread one or two below here for good info.

Long and short of it, the wing needs to provide lift to offset the weight of the plate and gear attached to it. So 18lbs of lift will NOT give you 18lbs of positive bouyancy if you have it attached to a 6lb plate and a tank that is 10lbs negative at the start of a dive.

The DiveRite Express site seems to recommend the Venture wing for use with the TransPac and single tanks, including 120cf tanks. From the website:

The Venture Wing is designed specifically for applications combining single cylinders with either the TransPac or TransPlate as well as a traditional backplate/harness configurations. The Venture wing's 30-pound capacity works with the largest of single aluminum or steel cylinders.

Ray

The transpac does not use a plate. But if I am neutraly bouyant with no air in the wing then wouldnt a 18lb wing give me 18lbs of positive bouyancy when fully inflated?
Is it to do with the lost bouyancy of my 6.5mm wetsuit at depth? My original BC had 10kg(22lb) of lift seemed to give me enough.

 

[Packhorse]

Diving a balanced rig is a good idea. It means being weighted so that with tanks almost empty you are still neutral close to the surface and can do your 3m (10 ft.) safety or deco stop without problem, and using tanks and other equipment which allow you to ditch excess weight if necessary and swim your rig to the surface at any point of the dive (namely when your tank or tanks are full and you are deep so that your wetsuit has compressed and lost most of it's buoyancy). For example, if you use a Heiser 190 (-62.3 lbs buoyant when full) then it's pretty much impossible to have a balanced rig because a normal person could not swim that up.

18 lbs wings are usually recommended for warm water diving to be used with an Al80 or similar tanks. From your describtion it seems that you would need more lift that that.

So it has nothing to do with you, your wetsuit and weightbelt being neutral and your BC, regs and tanks being neutal by them selves? eg a weight intergrated BC would not be a balance rig?

 

[fdog]

If you dive to, say, 80 fsw, you wetsuit will be squished flat and lose it's bouyancy. So your BC will need enough lift to offset your:

>cylinder when full, -16 lbs (if high pressure Faber 120), -5 lbs (if low pressure Faber 120)
>weight belt
>extra equipment, lights, etc.
>not much from the Transpac, unless you have a plate in it (not stock)

Given that you are diving with a 6.5mm, I'd estimate you are using a high-pressure Faber, since you are only using 15 lbs of lead. With this you'd need at least a 32 lb wing.

This would be a stretch to call a "balanced rig", mostly because ditching weight can still leave you 16 to 18 lbs heavy.

Maybe the double bladder wing is a good thing after all...you can have a bladder failure and still get home...


All the best, James

 

[*Floater*]

So it has nothing to do with you, your wetsuit and weightbelt being neutral and your BC, regs and tanks being neutal by them selves? eg a weight intergrated BC would not be a balance rig?

The different components don't have to be neutral by themselves for the rig to be balanced, but it wouldn't be a bad idea in case you need to take your rig off under water. Most people use integrated weights simply because that's more comfortable than using a weight belt, but you should still make sure you have enough ditchable weights to swim the rig up (but heavy lights and such can be counted as part of your ditchable weights).

 

[Packhorse]

If you dive to, say, 80 fsw, you wetsuit will be squished flat and lose it's bouyancy. So your BC will need enough lift to offset your:

>cylinder when full, -16 lbs (if high pressure Faber 120), -5 lbs (if low pressure Faber 120)
>weight belt
>extra equipment, lights, etc.
>not much from the Transpac, unless you have a plate in it (not stock)

Given that you are diving with a 6.5mm, I'd estimate you are using a high-pressure Faber, since you are only using 15 lbs of lead. With this you'd need at least a 32 lb wing.

This would be a stretch to call a "balanced rig", mostly because ditching weight can still leave you 16 to 18 lbs heavy.

Maybe the double bladder wing is a good thing after all...you can have a bladder failure and still get home...


All the best, James

Thanks for the replys. But I still do not quite get it. Surely your BC only needs to offset the buoyancy lost from your wetsuit at depth and the weight of your air at the start of your dive? (assuming you are neutral at the start of the dive with an empty BC). Now my 15L faber contains 3450 liters of air or 4.5kgs (10lbs). Mm. Ok now I get it, Im sure my wetsuit will lose more than 8lbs of boyancy at depth. I just dont see where the weight of your tank and gear come into it. Are these not offset by the amount of lead you use not your BC?

 

[*Floater*]

Thanks for the replys. But I still do not quite get it. Surely your BC only needs to offset the buoyancy lost from your wetsuit at depth and the weight of your air at the start of your dive? (assuming you are neutral at the start of the dive with an empty BC). Now my 15L faber contains 3450 liters of air or 4.5kgs (10lbs). Mm. Ok now I get it, Im sure my wetsuit will lose more than 8lbs of boyancy at depth. I just dont see where the weight of your tank and gear come into it. Are these not offset by the amount of lead you use not your BC?

That's essentially it, however, most people also like to have enough lift capacity so that their rig can float on the surface without them in it (in case they throw it in first or take it off in the water). So, for example, if someone is using a -6 lb plate, -10 lb tank (when full), -1 lb reg, -4 lb lights, then that's already -21 lbs of buoyancy and the wing would need to handle that if the person wants it to float the rig on the surface.