Halcyon 40# Evolve for 60# Evolve

[antattack]

Hey folks,

I'm about to start training on doubles. I have a Halcyon Evolve 40, but as a cold water dry suit diver 40# of lift is just about right for my single tank rig. The math says I need a bigger wing for doubles.

I'd like to trade for a Halcyon Evolve 60# wing, and I'm open to using another brand 55#- 60# of lift is what I'll require. We can true up a deal with money if need be.

Here's what I've got, let's make a deal:

Never wet Halcyon evolve 40# doubles wing
2 (XS SCUBA) Worthington lp85 with faber DIN valves Current hydro and vis, O2 clean.
Never wet Halcyon weight system
Never wet Halcyon storage pack system
Never wet Halcyon small SS backplate
Halcyon harness for backplate

Why do I have all this gear that's never been wet? I was in a buying frenzy when Wallins dive center closed, and when Aqua Safaris stopped carrying Halcyon gear.

PM Me

Regards,
Gary (Antattack)

 

[eelnoraa]

a bit off topic, but what makes you think 40lb is not enough for double lp85? a lot of people I know dive double HP100+stage with Evolve 40. You need enough lift, but after that it is NOT the more the better. 60lb wing will only make your diving harder

 

[divad]

I'm about to start training on doubles. I have a Halcyon Evolve 40, but as a cold water dry suit diver 40# of lift is just about right for my single tank rig. The math says I need a bigger wing for doubles.

What's the math?

 

[antattack]

Here's the math:


____________


With my Zeagle Ranger and a shell dry suit in salt water, with a single tank, I was diving:


Non Variable Buoyancy


Weight Belt -16
Integrated Weights -8
______
Total non variable weight: -24#


Variable Buoyancy
Empty Full Delta Total Full Total Empty
Genesis HP 80 -3.3 -9.3 6 -33.3 -27.3 <--- This resulted in a "Balanced Rig"

Sherwood AL 80 +3.4 -1.4 4.8 -25.4 -21.6 <--- Add 8# tank weights to get "Balanced"


Recently I changed a couple things. I moved to Steel HP 100s and Steel LP 85s. I also changed to the Halcyon Eclipse 40 Back Plate and wing. I also have an old HP Steel 80 that I might want to use because it's so tiny.


Non Variable Buoyancy


Back Plate and STA Weight: -8#
Weight Belt: -16
Trim Weights : - 4
_______
Total Weight - 28#


Variable Buoyancy
Empty Full Delta Total Full Total Empty
Genesis HP 80 -3.3 -9.3 6 37.3 31.3
Worthington LP85 -.7 -7.1 6.4 35.1 28.7
Worthington HP100 -2.5 -10 7.5 38 30.5


During rescue drills, I was using the HP 100 and it was full, when handed off to a buddy, my gear was just floating at the surface. Of course, I was nice and buoyant in my dry suit. There was only 2# of extra lift to keep my gear afloat. I didn't notice when I was wearing the gear because I was quite buoyant in my dry suit. So there is great value in actually TESTING if your gear works in a rescue situation.


If my old kit was "Balanced", then I'm over weighted by 3-4# in my new BCD.


What happens if I ditch 4#?


Variable Buoyancy
Empty Full Delta Total Full Total Empty
Genesis HP 80 -3.3 -9.3 6 33.3 27.3 <---Balanced
Worthington LP85 -.7 -7.1 6.4 31.1 24.7 <---??
Worthington HP100 -2.5 -10 7.5 34 26.5<---Balanced



Well there you go. I've tested this with the HP100 at 400# of air at 10 FSW, and I can hover. I may need to add 4# for the lp85, but I think I'll get rid of the two LP85s anyway. Anyone want to trade two LP85s for one HP100? (DIN only need apply.)


Provided I don't add a bunch of negatively weighted gear to my rig, I'll have a 15% lift reserve for my gear. Considering I have about another 20# of lift in my dry suit or another 10# of lift in a wet suit at the surface, and the fact that I'm a bit buoyant in my birthday suit, this seems like a safe, balanced rig.


Things get more interesting as I look at my doubles rig, which has a Halcyon Evolve 40# wing.


Non Variable Buoyancy


AL Back Plate: -2#
Weight Belt: -16
Manifold/ redundant reg - 2
Band and hardware - 1
_______
Total Weight - 21#


Variable Buoyancy
Empty Full Delta Total Full Total Empty



Worthington HP100s -5 -20 15 -41 -26


The rig is too heavy. Since the wing has never been in the water, I have to make a decision- can I dive this thing with less weight? Let's see.




Non Variable Buoyancy


AL Back Plate: -2#
Weight Belt: -6
Manifold/ redundant reg - 2
Band and hardware - 1
_______
Total Weight - 11#


Variable Buoyancy
Empty Full Delta Total Full Total Empty



Worthington HP100s -5 -20 15 -31 -16



Nope, it doesn't work. Why? Because at the end of the dive, I'll be popping to the surface like a cork. I need ~27# negative at the end of the dive to be able to hover at 15'fsw without working. That's just what happens in a dry suit in 47 F water.


Which means that in cold water, using a dry suit, I'll need a bigger wing. The next size up is the mighty 60# wing. That should give me a generous safety margin- even if I have to drag that big donut through the water.


Now I have to face the most daunting decision in my diving career- Dual bladders wing or single? All the DIR folks will sneer at me if I have a dual bladder back plate, but it seems so fancy with all those hoses and valves... So I'm thinking of using the next larger Halcyon. I like the donut shape and have not tried the horseshoe style wing.

OK, take me to school

 

[eelnoraa]

Things get more interesting as I look at my doubles rig, which has a Halcyon Evolve 40# wing.


Non Variable Buoyancy


AL Back Plate: -2#
Weight Belt: -16
Manifold/ redundant reg - 2
Band and hardware - 1
_______
Total Weight - 21#


Variable Buoyancy
Empty Full Delta Total Full Total Empty



Worthington HP100s -5 -20 15 -41 -26


The rig is too heavy. Since the wing has never been in the water, I have to make a decision- can I dive this thing with less weight? Let's see.

So at the beginning of the dive with full doube HP100, your rig weight 25lb (41lb -16lb), because your weight belt does NOT belong to the rig, it is on you. If you have to ditch your rig, 40lb of lift should float your rig just fine.

What you forget to count here is the postive buoyancy of yourself (+ drysuit). If you are properly weighted, you are only over weighted by the weight of your gas at the beginning of the dive, that is 15lb (quoted above). So 40lb of lift is still good here.

Last case, you have a total flooded drysuit. Again, quoted above, your total negative balast is 26lb, that means your drysuit is +26lb. If it flood at the begininng of the dive lost all the 26lb, you are -41lb. 40lb lift isn't quite cut here, but that is when you ditch your weight belt. If you do so, you are only -25lb, so the evolve 40 is still good here.

---------- Post Merged at 08:28 PM ---------- Previous Post was at 08:20 PM ----------

I would recommend you to keep your Evolve 40 here, but better yet, talk to the instructor that you are training doubles with.

 

[antattack]

Well thought out Eelnoraa. And, in fact that it's a comfortable and practical way to dive- I'm fine with the result that you just articulated. Perhaps I'll double check again with my Tech instructor, but the PADI manual indicates that I have to be able to float all my gear during a rescue drill on my BCD, With double 100s full, I won't be able to do that.

I'll double check, but it all comes down to what my instructor will let me train with.

Incidentally I had a wrist seal tear at 100 FSW last year- While I was wet and a little cold, the suit still held air quite nicely in a prone position. So I'm pretty comfortable knowing that I can swim the rig up in the worse case. It all comes down to what the instructor demands.

---------- Post Merged at 08:32 PM ---------- Previous Post was at 08:32 PM ----------

I'll close the thread while I confer with my instructor. TY