dry suit buoyancy

[Thalassamania]

All of Harris' stuff is really good. Keep in mind that his views are filtered through his obsession and that is diving in really swift moving rivers.

 

[dsteding]

It sounds like I am in the minority in this group, but I control buoyancy almost exclusively with my dry suit. I have done it both ways and I think it depends on the diver, the suit and undergarments the diver is wearing, and how much weight they have. I have found, for me, I am more comfortable, use less weight and stay warmer when all the air goes in my suit.

Amy, do you know why PADI teaches it this way, when it seems that the majority of divers use their DS?

 

[Thalassamania]

I'm not sure that eveyone means the same thing when they say that they "control their buoyancy with their dry suit."

 

[Doc Intrepid]

Amy, do you know why PADI teaches it this way, when it seems that the majority of divers use their DS?

See Cancun Mark's post #11, a portion of which is quoted below (from the PADI website):

"4. Adjusting your buoyancy underwater.
a. Underwater, you add air or argon only to the suit. Do
not use your BCD.
1. This avoids a suit squeeze (severe pinching due to
compression as you descend).
2. You’re not having to control two systems —
adding or releasing gas as you change depth.

I can only speculate, but it seems that PADI think it is too complicated to manage the BCD and the DS inflation and deflation at the same time."

PADI's position, per their own published assertions, appears to be that (a new student or new drysuit diver) is not initially having to control two separate bouyancy systems - the BC/wing AND the drysuit - simultaneously while descending or ascending.

Agree or disagree, but this appears to be PADI's rationale for having the student focus only on adding gas to the drysuit and not to the BC/wing while submerged.

FWIW.

YMMV.

 

[Thalassamania]

Also keep in mind that PADI's mindframe is a single AL 80, with a reserve of 500 lbs. That's not much weight shift.

 

[Doc Intrepid]

thats a good point too.

the more weight you add (double tanks, stages, heavy video cameras, whatever) the more problematic 'equilibrium' becomes.

what works for one drysuit diver in an 80 may not work for another with a couple steels...

 

[Thalassamania]

thats a good point too.

the more weight you add (double tanks, stages, heavy video cameras, whatever) the more problematic 'equilibrium' becomes.

what works for one drysuit diver in an 80 may not work for another with a couple steels...

What works for ME in an 80 does not work for ME with a couple of steels, and I can shift about 15 lbs on my lungs.

 

[limeyx]

It sounds like I am in the minority in this group, but I control buoyancy almost exclusively with my dry suit. I have done it both ways and I think it depends on the diver, the suit and undergarments the diver is wearing, and how much weight they have. I have found, for me, I am more comfortable, use less weight and stay warmer when all the air goes in my suit.

I honestly dont know how you manage it -- I'd love to meet someone that used just the drysuit because as soon as I add even a little bit too much gas to the suit, I start to feel like the michelin man and flail around like a moron.

Also, not sure I can get 20+ pounds of lift out of my drysuit.

 

[scubascobey]

I've been thinking a lot about everyone's input and advice, plus I read the link from Dive Bear which was excellent.

I have another question: Does anyone know generally how much lift and drop in feet can be achieved using just lung inhale and exhale (not using any DS or BC)? I'm sure that it depends on the depth you're at. Let's assume you're at 30-40 feet deep.

Thanks for all the great replies.

 

[Thalassamania]

I've been thinking a lot about everyone's input and advice, plus I read the link from Dive Bear which was excellent.

I have another question: Does anyone know generally how much lift and drop in feet can be achieved using just lung inhale and exhale (not using any DS or BC)? I'm sure that it depends on the depth you're at. Let's assume you're at 30-40 feet deep.

Thanks for all the great replies.

Depth does not matter and it depends on the size of your lungs. I've taught small women who could only shift about six lbs and large men who could shift 16 lbs. The comfortable amount that you can go plus and minus on is about a quarter of that total, (I have 15 lbs of lung volume, so I can comfortably go "shy" of four lbs up or down from my mid point).