Hi Kevin,

There are actually two issues here.

1) Will the wings float your "kit" on the surface;

and the MUCH more important issue

2) If your wings fail can you swim your kit to the
surface with full tanks.

When diving dry in a tri-laminate drysuit, the suit
and your undergarment provides the same amount of
buoyancy from the surface to any depth you dive (since
you add air to your suit to "take the pinch off" as
you descend and vent the same as you ascend).
Therefore, if you figure that you need 24# of weight
to be neutral at 10-15 ft with 300-500 psi in your
tank, you would need the same 24# of weight at 99 ft.
As a result you can use non-ditchable weight to
provide this negative buoyancy. Some of it will come
from your kit (tank, regulator etc) and the rest can
be added as a V-weight between the tanks in a set of
doubles or in the form of a SS backplate and/or
weighted single tank adapter as you mentioned.

Then, at the beginning of your dive you will be
negative only by the weight of the air in your
tank(s). For an aluminum 80 that would be about 6-7 #
for your PST 95 that would be 8-9 #. If you had a
catastrophic wing failure upon reaching the bottom in
100 ft of water with full tanks, could you swim the
8-9 # to the surface. I would think yes.

This is sometimes referred to as diving a balanced rig
- a kit in which you are neutral at 10-15 ft with
300-500 psi in the tanks and wings empty. 

BUT you are diving a wet suit. That provides another
challenge. Your wet suit that provides, say 24 # of
buoyancy at the surface will only provide 25%
(approximately) of that buoyancy at 100 ft. That means
that now you are 18 # negatively as a result of wet
suit compression and another 8-9 # negative due to the
weight of the air. Can you swim 27 # to the surface
without over-exertion and the ensuing problems?

That is why it is recommended that when diving a
wetsuit you use 1) aluminum tank(s), 2) aluminum
backplate and 3) keep your weight on your belt
(ditchable).

As for question number 1, rig up your kit, inflate the
wings and see if they will float it in a pool. Unless
you have added a lot of non-ditchable weight to the
PST 95, the 27 # wing should work fine.

Dave Dalton


--- Metcalfe Kevin  J COCA
<kmetcalfe@ns*.na*.mi*> wrote:
> I'm a recreational diver in Northern California.  I
> dive in a 7mm wet suit
> and use a PST 95 tank.  I recently acquired a SS
> back plate and am close to
> purchasing a Halcyon wing and a single tank adapter.
>  Will the 27 lb wing
> provide sufficient lift for my diving and equipment?
>  I demoed a Halcyon
> system in September with a 27 lb wing and used 14
> lbs of lead if that helps
> any.
> 
> To compound the previous question, the STA that I'm
> going to buy is the
> steel one that Scott Koplin makes.  I am considering
> getting the one that he
> melts the lead into and weighs about 6 lbs.  That
> leaves me wearing only 8
> lbs of ditchable weight.  
> 
> So I guess the first question is, Is 27 lbs enough
> lift for me with a normal
> STA?  Second, If yes to question one, then would the
> 6 lb STA push me over
> the edge.
> 
> And yes, I know that it would be better to dive dry,
> but one thing at a
> time.
> 
> Thank you,
> 
> 
> Kevin Metcalfe
> kmetcalfe@ns*.na*.mi*
> 925-246-5938
> DSN 350-5938
> 
> 
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> 
> 
> 


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