Wing Lift For Double Hp100

[Schwob]

but it takes a lot of gas and your buoyancy swings happen quickly.

Just trying to understand what you mean in the context of ywo AL 40 deco bottles, when you say "and your buoyancy swings happen quickly."

 

[RyanT]

@Schwob, a couple of AL 40 bottles (or AL 80s) get neutral or a little floaty pretty fast. A big steel deco bottle will remain negative and you have to offset the negative buoyancy with additionalgas in your wing. A 60lb wing will obviously float a lot of negative weight underwater. But, in order to offset the weight, you have to put a lot of gas in the wing. The more gas you have in your wing, the more it expands from 30' to the surface. With a large volume of gas in your wing, it expands rapidly and very quickly increases how buoyant you are. If you aren't paying careful attention and don't vent quickly enough, you can lose control of your buoyancy. This entails blowing a safety stop and/or rocketing to the surface.

 

[JustKeepSwimming]

Can a 60 lb wing lift hp100 doubles with an hp100 deco bottle (3 hp100s)?

With 0-25 dives, you should be more concerned with working on trim and buoyancy than slinging tanks.

 

[Schwob]

@Schwob, a couple of AL 40 bottles (or AL 80s) get neutral or a little floaty pretty fast. A big steel deco bottle will remain negative and you have to offset the negative buoyancy with additionalgas in your wing. A 60lb wing will obviously float a lot of negative weight underwater. But, in order to offset the weight, you have to put a lot of gas in the wing. The more gas you have in your wing, the more it expands from 30' to the surface. With a large volume of gas in your wing, it expands rapidly and very quickly increases how buoyant you are. If you aren't paying careful attention and don't vent quickly enough, you can lose control of your buoyancy. This entails blowing a safety stop and/or rocketing to the surface.

Yeah, thanks, I am with you on all that (a lot of air in the wing due to being set up to need the lift causing faster swings). I just didn't get how the two AL 40s contribute to that... (as opposed to larger deco tanks with more gas = more weight change to weigh for = bigger wing volume swing as with 2 AL40s - or)?

 

[CAPTAIN SINBAD]

More bottom time. I don't believe in alu cylinders as to toxicity of imperceptible oxidation over the long term. I believe steel oxidation is more noticeable and not as harmful for the lungs.

Well others have already addressed your toxicity concern. I am more concerned that if your dive count is accurate then what exactly are you attempting to do for which you are needing three HP-steels? If you were certified for decompression diving then a lot of concerns you have should already have been addressed. If you are not certified for decompression diving then what would three HP tanks serve while you are within NDL limits?

 

[JustKeepSwimming]

+1 Captain SinBad

 

[RyanT]

@Schwob, oh I see your question. When full, a couple of AL 40s will each be a couple of pounds negative, so at the start of the dive they add some weight. A single HP 100 when full is even heavier than two AL 40s. At the end of the dive, AL 40s (or AL 80s for that matter) start to get a little floaty, whereas the HP 100 will remain negative. So on ascent/deco, you don't need to add much gas to compensate for the AL bottles. You will have to keep more gas in your wing to offset a heavy steel deco bottle.

 

[decompression]

Can a 60 lb wing lift hp100 doubles with an hp100 deco bottle (3 hp100s)?

Steel deco bottles should be avoided.......IMO.