Warm water doubles wing size?

[u5agi]

For those of you who are diving doubles in warm water, what wing size do you recommend? Is the 45 lbs enough or do you recommend the 55 lbs?

I'll be relocating to SE Asia and will be diving primarily warm water from now onwards, so having a wing for diving dry/steel LPs will not be important.

Any advice appreciated!

 

[cool_hardware52]

For those of you who are diving doubles in warm water, what wing size do you recommend? Is the 45 lbs enough or do you recommend the 55 lbs?

I'll be relocating to SE Asia and will be diving primarily warm water from now onwards, so having a wing for diving dry/steel LPs will not be important.

Any advice appreciated!

My advise:


The minimum lift required for any Open Circuit Application is the greater of; the lift necessary to float your rig without you in it, or the maximum total loss of buoyancy of your exposure suit.

The first requirement is a good idea if you remove the gear, it would be nice not to have it disappear, check with full tanks.

The second requirement, i.e. enough lift to offset the loss of buoynacy of your suit can be determined by weighting just your suit (without you in it) until it sinks. This weight represent the maximum potential loss of buoyancy. For neoprene IIRC you need to go to about 165 fsw for total compression.

The above holds true if you can acheive neutral buoyancy at the surface with no air in your BC.

If you were to be carrying other heavy loads such as multiple stages, scooter, tools etc and could not acheive neutral buoyancy at the surface without inflating the BC then you need to add to the above value.

It might also be possible that in very tropical conditions, with minimal exposure suit and a pair of heavy steel doubles, that you might be negative with no air in the BC, but in these cases it is likely that the first rule will govern, i.e. enough lift to float the rig alone.

I think you wil find that surprisingly small wings will suffice.


cheers,



ch

 

[Curt Bowen]

For those of you who are diving doubles in warm water, what wing size do you recommend? Is the 45 lbs enough or do you recommend the 55 lbs?

I'll be relocating to SE Asia and will be diving primarily warm water from now onwards, so having a wing for diving dry/steel LPs will not be important.

Any advice appreciated!

This will depend on the size of doubles, stainless or ABS back plate, stages used etc...

 

[WaterDawg]

I dive double 80's in a 3 and 5 mil suit a 40lbs is more than enough even w/ a 40cf bottle

 

[u5agi]

Here's my setup - Luxfer ALU80 doubles (2x 1.4lbs full), Luxfer ALU40 stage (0.8lbs full), SS BP (6 lbs), primary light (2 lbs), 2 backups (3lbs), manifold & bands (5lbs?), 14 lbs of weight.

Comes up to 33.2 lbs... let's say 35 lbs. It looks like a 45 lbs wing will suffice?

 

[cool_hardware52]

Here's my setup - Luxfer ALU80 doubles (2x 1.4lbs full), Luxfer ALU40 stage (0.8lbs full), SS BP (6 lbs), primary light (2 lbs), 2 backups (3lbs), manifold & bands (5lbs?), 14 lbs of weight.

Comes up to 33.2 lbs... let's say 35 lbs. It looks like a 45 lbs wing will suffice?

U5agi,

I'm assuming that you are using a 14lb weight belt, not 14 lbs attached to your harness.

The total negative weight of your rig less your weight belt is the first consideration. By your list I'd say ~ 20lbs. If you ditch the rig at the surface and want it to stay there then a min of 20lbs is required.

What is unknown is the total positive buoyancy of your Exposure suit. If you are diving in a wetsuit using scuba, not a rebreather, about the only thing that will lose buoyancy is your suit. It will be maximum buoyant at the surface and will be reduced to zero at about 165 fsw.

It is this change in buoyancy that you need to "compensate" for. If you know what the max positive of your suit is then you can easily determine what the max buoyancy you can loose.

Don't be surprised to find that 20-30 lbs is more than enough.
The real challenge is to find a doubles wing with minimal lift.

It's even harder to understand why 80-90-100 lbs wings are even made.


Regards,



ch

 

[u5agi]

CH,

Definitely using a weight belt!

The 3mm exposure suit has about 10 lbs of buoyancy, so with a 6 lb BP, I only need another 4 lbs on the belt. The Luxfer ALU80s are -4.4 lbs empty each and the ALU40 is -2.2 lbs empty, requiring ~10 lbs on the belt to compensate. Total weight on belt = 14 lbs.

Maximum buoyancy lost below 165 ft with full tanks = 28 lbs. That's really not much at all...

Great discussion!

Thanks,
Joseph

 

[CRDiver]

Given what everyone has already stated, the Dive Rite TrekWing or OMS 45lb. non-banded bladder would be pretty close to ideal. Plus, keep in mind when shopping, lift ratings on virtually all bladders are overrated by 10% or more.

 

[cool_hardware52]

Given what everyone has already stated, the Dive Rite TrekWing or OMS 45lb. non-banded bladder would be pretty close to ideal. Plus, keep in mind when shopping, lift ratings on virtually all bladders are overrated by 10% or more.

If it's not too "commercial" of me I"d suggest our LCD50 as near ideal....follow the link below.

As stated by CR, Lift values may not be spot on. One factor is manufacturing tolerances, by the time something gets cut and sewn up the actual volumes may not be what was originally designed, 10% of a 45lbs wing is just 4.5 lbs or ~124 cu in. This volume can easily be lost if the shell varies even slightly.

What we have found is much bigger player is how the wing is constrained by the plate and Tanks. Depending on where the wing is secured on the plate, i.e. what set of grommet holes are used the top arc of the wing may be trapped by the plate.

In addition different doubles sets may also prevent certain portions of the wing from inflating.

If in doubt first weigh the wing empty. Then assemble the goods as you intend to use them, and fill the bladder with water, carefully removing all the air.

Dissassemble the rig and weigh the full wing. The difference in the empty and full weights of the wing = the available max lift. (If you use fresh water and dive in SW your measured values will be slightly less than actual)

 

[Curt Bowen]

CH,

Definitely using a weight belt!

The 3mm exposure suit has about 10 lbs of buoyancy, so with a 6 lb BP, I only need another 4 lbs on the belt. The Luxfer ALU80s are -4.4 lbs empty each and the ALU40 is -2.2 lbs empty, requiring ~10 lbs on the belt to compensate. Total weight on belt = 14 lbs.

Maximum buoyancy lost below 165 ft with full tanks = 28 lbs. That's really not much at all...

Great discussion!

Thanks,
Joseph

Think about using a tube weight in the middle of the doubles and forget the weight belt.