30 or 40 lb. lift on Halcyon Eclipse?

[Vayu]

How about a 35#

-V

 

[cool_hardware52]

Thanks for the input. It's tough to make a decision when you get numerous, differing opinions. Tough to figure out what's best.

This is from a link that was posted earlier from the bay area underwater explorers.

http://www.baue.org/faq/wing_size.html

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"For example, if you have a single steel tank, steel back plate, canister light, argon system, and 14lb of integrated weight then 36lb lift is probably not enough to keep the rig from sinking if you doff it at the surface.

Single aluminum 80, two-piece 6.5mm wet suit:

The breathing gas weighs 6lb or less, and the wet suit could lose up to 24lb of lift due to compression if you go deep enough. So a 30lb wing should be adequate. Note that the 30lb should be sufficient to float the rig at the surface, unless there is significant weight worn integrated with the BP/harness.

Single low pressure steel 95, trilaminate drysuit:

"The breathing gas weighs 7lb or less, we would like at least 10lbs for surface flotation (more for rough conditions), and drysuit divers often carry a little extra weight for warmth. Then we must consider that a steel 95 is at least -2lb negative (some makes are more negative), a steel backplate is -6lb and the canister light is usually at least -2lb. A 27lb wing might be sufficient for this configuration and some divers have successfully used a 27lb with this configuration. However more divers opt for having a little more margin and choose the 36lb wing, which should be more than sufficient for most applications. If significant amounts of integrated weights and/or non-ditchable weights are used a 45lb wing may be more appropriate."

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In both the above cases, I'm looking at a decent amount of integrated weight, maybe 12lbs with an AL80 and less in the case of steel. In both cases of integrated weight it suggests going with a higher lift capacity.

Here's the thing...maybe someone can shed some light on something I may be missing. Right now, with a 7 mil wetsuit, I'm using around 24 lbs. with an AL80 tank. (Even less with a steel tank). Let's stick with the AL80 for this example...At the beginning of a dive, the AL80 is roughly 4 lbs negative, so i'm looking at around 28 pounds that my current BC needs to handle if I need to take it off and float it for some reason (Seaquest Balance BC, weight integrated). It has around 36 lbs. lift I believe. More than adequate.

However, Let's say I continue to use an AL80 with the BP/W and my wetsuit. I'm still looking at needing ROUGHLY the same weight, just in a different combination, correct? So, with the 5lb backplate, 6lb STA, I still need roughly 13lbs more or less..handled with the Halcyon ACB system . (I'm not going to use a weightbelt. (Don't want to, and don't have to). I thought, according to what I have read, that you want to get as much weight off you waist as you can and move it towards your back. The ACB is ditchable if need be. With a steel tank, I can just reduce the amount of weight in the pouches even more.

So, with a full AL80, i'm still looking at roughly 28 pounds that the BP/W needs to handle if I have to take it off and float it. That doesn't give much wiggle room for the 30lb wing, due to the fact that I might have a primary canister light, and backup lights. So, is my math wrong here? Am I missing something? Also, if I go to a DS, which I plan on doing shortly, won't I need to tack on more weight anyways to compensate for the thick undergarment weight?....So wouldn't the 40lb wing be a better choice. Hopefully someone can explain what I'm missing here. Thanks

If you want to know how buoyant your wetsuit is, take it off, roll it up and throw it in the pool, add lead 'till it's neutral. Here again you will have learned what the max possible buoyancy you can loose from wetsuit compression. You need to go to ~165 to have your wetsuit compressed to zero.

Another thing to remember. Your current BC is most likely 3-5 lbs positive when empty. Don't believe me? Empty the bladder, throw it in the pool and watch it float. Add lead 'till it's neutral. A BP&W will not be positive.

Wetsuits compress and so do DS undergarments, quite a bit in the first ~30 ft of depth. If you are diving with a single tank, and a 5mil or thicker wetsuit, you do not need to be overweighted at the surface at the beginning of the dive by the weight of the gas you will be breathing. How can you hold your shallow stop at the end of the dive when you are 5-6 lbs lighter? Easy, at 15 or even 10 ft your wetsuit is compressed.


You say you currently carry 24 lbs with an AL80. Lets assume your BC is 5 lbs positive
24 - 5 = 19
Lets assume you are overweighted by ~4 lbs (weight of gas)

19-4 = 15 lbs.

Backplate = ~6 lbs
Weighted STA or Weight plates = ~6 lbs.
12 lbs.

15 - 12 = 3 lbs in weight belt, even if you aren't currently overweighted by the weight of the gas you's still need only ~7 lbs in a weight belt.

A 6 or 8 lbs weight belt is almost unnoticed, and is far less expensive than weight pockets. If you ultimately switch to a steel tank the belt goes away.

For single tank diving, in a 5 mil or greater wetsuit I like to set people up to be neutral at the surface (eyelevel) at the start of the dive (full tank) with no gas in their wing.

It's much easier and more accurate to check buoyancy at the surface then at the mythical 500 psi and 15 ft depth. At the surface, edge of the pool, swimstep, platform etc. you can have a bag 'o' lead handy, you can more easily force yourself to STOP SWIMMING. This provides far more reliable results than trying to hold 15 ft depth, while you continue to breathe your tank. There never seems to be a bag of lead at 15 ft either.

You will want to confirm your weighting of course by making a shallow stop with near empty tank under controlled conditions.

My goal is to have the absolute minimum weight on my person. Makes all aspects easier, easier to make the entry, easier to maintain buoyancy control.

Good luck,


Tobin

 

[DiegoDiver]

If you want to know how buoyant your wetsuit is, take it off, roll it up and throw it in the pool, add lead 'till it's neutral. Here again you will have learned what the max possible buoyancy you can loose from wetsuit compression. You need to go to ~165 to have your wetsuit compressed to zero.

Another thing to remember. Your current BC is most likely 3-5 lbs positive when empty. Don't believe me? Empty the bladder, throw it in the pool and watch it float. Add lead 'till it's neutral. A BP&W will not be positive.

Wetsuits compress and so do DS undergarments, quite a bit in the first ~30 ft of depth. If you are diving with a single tank, and a 5mil or thicker wetsuit, you do not need to be overweighted at the surface at the beginning of the dive by the weight of the gas you will be breathing. How can you hold your shallow stop at the end of the dive when you are 5-6 lbs lighter? Easy, at 15 or even 10 ft your wetsuit is compressed.


You say you currently carry 24 lbs with an AL80. Lets assume your BC is 5 lbs positive
24 - 5 = 19
Lets assume you are overweighted by ~4 lbs (weight of gas)

19-4 = 15 lbs.

Backplate = ~6 lbs
Weighted STA or Weight plates = ~6 lbs.
12 lbs.

15 - 12 = 3 lbs in weight belt, even if you aren't currently overweighted by the weight of the gas you's still need only ~7 lbs in a weight belt.

A 6 or 8 lbs weight belt is almost unnoticed, and is far less expensive than weight pockets. If you ultimately switch to a steel tank the belt goes away.

For single tank diving, in a 5 mil or greater wetsuit I like to set people up to be neutral at the surface (eyelevel) at the start of the dive (full tank) with no gas in their wing.

It's much easier and more accurate to check buoyancy at the surface then at the mythical 500 psi and 15 ft depth. At the surface, edge of the pool, swimstep, platform etc. you can have a bag 'o' lead handy, you can more easily force yourself to STOP SWIMMING. This provides far more reliable results than trying to hold 15 ft depth, while you continue to breathe your tank. There never seems to be a bag of lead at 15 ft either.

You will want to confirm your weighting of course by making a shallow stop with near empty tank under controlled conditions.

My goal is to have the absolute minimum weight on my person. Makes all aspects easier, easier to make the entry, easier to maintain buoyancy control.

Good luck,


Tobin

Very good points. Thanks.

I was always told to calcualte buoyancy at the surface with a near empty tank. I never thought about the wetsuit compression compensating for the difference at the safety stop depth.

Also, I never factored in the positive buoyancy of my BC. Plus, I own a PST E8-130 tank, so......According to what you wrote, I can pretty much....with fine tuning....eliminate the need for the extra weight in the ACB system.

It looks like this tank has around 9lbs of gas. -10 full, -1 empty. Will the wetsuit have that much in compression to compensate at 15ft, or will a need a just a couple of extra pounds?

It looks like all I will need is the Backplate and weighted STA. When I go to a drysuit, and do need a couple of extra pounds, I can always add them later.

Forgetting about my buoyancy calculation for now, the only concern I have which wasn't addressed however, is the capability of the Wing being able to handle the weight of my rig, floating at the surface (not including me) at the beginning fo the dive if I need to take it off. It has to be able to handle the weight.

E8-130 -- -10 Full
Backplate -6
Weighted STA - 6
Regs, lights, etc. 5 lbs maybe....
Other possibilities???

I'm looking at close to 28lbs that the rig needs to handle give or take. I understand that the 30lb wing might be right in terms of buoyancy for me now, but what about its capability of handling the rig without me in it? Isn't that a little too close to call?

Thanks, I'm getting there.

 

[cool_hardware52]

Very good points. Thanks.

I was always told to calcualte buoyancy at the surface with a near empty tank. I never thought about the wetsuit compression compensating for the difference at the safety stop depth.

Also, I never factored in the positive buoyancy of my BC. Plus, I own a PST E8-130 tank, so......According to what you wrote, I can pretty much....with fine tuning....eliminate the need for the extra weight in the ACB system.

It looks like this tank has around 9lbs of gas. -10 full, -1 empty. Will the wetsuit have that much in compression to compensate at 15ft, or will a need a just a couple of extra pounds?

It looks like all I will need is the Backplate and weighted STA. When I go to a drysuit, and do need a couple of extra pounds, I can always add them later.

Forgetting about my buoyancy calculation for now, the only concern I have which wasn't addressed however, is the capability of the Wing being able to handle the weight of my rig, floating at the surface (not including me) at the beginning fo the dive if I need to take it off. It has to be able to handle the weight.

E8-130 -- -10 Full
Backplate -6
Weighted STA - 6
Regs, lights, etc. 5 lbs maybe....
Other possibilities???

I'm looking at close to 28lbs that the rig needs to handle give or take. I understand that the 30lb wing might be right in terms of buoyancy for me now, but what about its capability of handling the rig without me in it? Isn't that a little too close to call?

Thanks, I'm getting there.

If you are currently using 24 lbs with a BC that's likely positive, why do you think you will need 28 lbs with a non buoyant BC?


An Al 80 will swing about 5lbs from 3000 to 500 psi , and your E8-130 will swing about 9 lbs from 3442-500 psi. 9 lbs might be a bit more than your wetsuit will compress at 10 ft. Depends on the wetsuit.

Tobin

 

[KOMPRESSOR]

Forgetting about my buoyancy calculation for now, the only concern I have which wasn't addressed however, is the capability of the Wing being able to handle the weight of my rig, floating at the surface (not including me) at the beginning fo the dive if I need to take it off. It has to be able to handle the weight.

This is a question most "DIR" people I know seem to answer with something other than an answer to the question... With the fixed weights you'll most likely have on your rig when you dive well adjusted with a trilam ds, the 30# rig is likely to sink if the tank is full. -Like if you have to abort a dive and for some reason need to get out of the rig.

Since I dive with a thick neoprene ds myself I always carry the "last" 6-8 lbs of my ballast in a waistbelt, under the web. So the lift problem you're worried about doesn't really concern me and my diving. But for real, I'm no longer that certain this problem will be a real one, even if I was very upset with this minimalism on bouyancy in the beginning of my wing/bp career!

 

[Mike Newman]

I go with the majority of replies - and suggest getting a 40lb wing would be the right way to go. It's especially relevant in 'cold water' environments. The drag difference between 30 and 40 is negligible and the margin of safety in the 40 will do no harm.

 

[DiegoDiver]

If you are currently using 24 lbs with a BC that's likely positive, why do you think you will need 28 lbs with a non buoyant BC?


An Al 80 will swing about 5lbs from 3000 to 500 psi , and your E8-130 will swing about 9 lbs from 3442-500 psi. 9 lbs might be a bit more than your wetsuit will compress at 10 ft. Depends on the wetsuit.

Tobin

??????

I never said anything about needing 28lbs....maybe you misread what I wrote.....that is what the weight WILL BE on the rig at the beginning of the dive If I need to take it off. Again, 10 pounds tank (full), 12 pounds between STA and Backplate, a few pounds here and there for what the canister light, regs, backup lights etc, weigh on their own, bringing me up to close to 28 lbsl, give or take a few.

To be honest, I never really concerned myself with needing to float my current BC...I just recently figured out that that was an important concern to deal with.

Thanks again for the wetsuit compression answer, I guessed it wouldn't compress that much.

 

[cool_hardware52]

??????

I never said anything about needing 28lbs....maybe you misread what I wrote.....that is what the weight WILL BE on the rig at the beginning of the dive If I need to take it off. Again, 10 pounds tank (full), 12 pounds between STA and Backplate, a few pounds here and there for what the canister light, regs, backup lights etc, weigh on their own, bringing me up to close to 28 lbsl, give or take a few.

To be honest, I never really concerned myself with needing to float my current BC...I just recently figured out that that was an important concern to deal with.

Thanks again for the wetsuit compression answer, I guessed it wouldn't compress that much.

You stated you currently use ~24 lbs with a jacket BC.

Then you list 27-28 lbs of gear, including a 6 lbs STA. If you don't need 27-28 lbs why use a 6 lbs STA? Leave it off and you are back to 21-22 lbs. which may be pretty close.

Tobin

 

[DiegoDiver]

You stated you currently use ~24 lbs with a jacket BC.

Then you list 27-28 lbs of gear, including a 6 lbs STA. If you don't need 27-28 lbs why use a 6 lbs STA? Leave it off and your back to 21-22 lbs. which may be pretty close.

Tobin

This discussion is getting confusing...

I'm burnt out now...I guess I will just take the time and experiment in the water until I get it to where I want to be. Thanks for the time.

 

[lamont]

If you're going with weight that is all attatched to your BP/W (ACB, SS STA, weighted STA, etc) and no weightbelt, in cold water, then you probably need the 40# to float it at the beginning of the dive. 30# will likely be cutting it pretty close, and if you step up to thicker undies and more weight in the future then you'll definitely need the 40#er. The math will vary with individual differences and the amount of weight that you need to get your drysuit down, but it'll probably be around 15-20# to keep your drysuit down plus 10# for the gas on your back.