Frequency of advanced divers practicing CESAs ? [Poll]

[KenGordon]

Force of will isn’t about about muscle but being in control. Crude balance is down to kit but in the end the diver has to be shoving things about as appropriate and maintaining balance. If tied up like a turkey with no way to adjust anything then they are going to have a hard time.

There is flexibility about where exactly a weight belt goes and where the cylinder is relative to the BCD or wing.

The diver can also keep their arms forward or back and decide how much to bend or extend their legs. Depending on suits and so forth arms might be relatively negative or buoyant.

It is possible to deal with quite a lot of apparent off balance kit. Stuff like stage cylinders, heavy torch batteries and so forth. That isn’t done by placement of a couple of weights half way up a cylinder.

 

[MichaelMc]

I find force of will / active extending/retracting or finning important when I’m inherently unstable due to a rather negative tank on my back. I just like using hips to shoulders and lead to get my crude or static trim as good as possible. Then I need arms, legs and finning less; sometimes not needing even an ankle twitch, though my gear doesn’t change during the dive.

 

[TMHeimer]

Wow, complicated stuff. We getting off the subject? I see a 2nd vote joined me on CESA more than once monthly. Did one today from 20'. Am OK.

 

[yle]

'Trim by will', or trim by 'how' you tense your muscles, (not where you hold your body, but how you tense), I always find fascinating. I don't think gravity cares about either.

I think you misinterpreted Ken's use of "will". He didn't mean you can simply wish yourself into a certain position. I'm sure he was referring to the idea that experienced divers subconsciously make subtle changes to their body position to adjust their trim. These subtle changes shift a diver's center of mass and center of buoyancy slightly... and gravity does "care" about the position of our center of mass, while the water cares about our center of buoyancy. The combined affection determines a diver's equilibrium position... i.e. their "trim".

It seems that Ken's point was that moving around lead weights is useful for coarse adjustments to a diver's trim, while the fine adjustment has to come from subtle, subconscious muscle control.

I find force of will / active extending/retracting or finning important when I’m inherently unstable due to a rather negative tank on my back. I just like using hips to shoulders and lead to get my crude or static trim as good as possible.

I think you're basically saying here the same thing that Ken was arguing. Use weights to get "crude or static trim as good as possible", but fine tuning has to come from subtle muscle control.

 

[boulderjohn]

I thought a would relate a story from this weekend. It will have some bearing on this issue.

I was doing a technical dive in which I did something unusual. I had my doubles and a stage bottle for bottom gas, but I breathed down the doubles pretty far before going to the stage (just before ascent) because I wanted to get the doubles down in volume because of future plans. We finished the dive, and I unclipped the stage and deco bottles before something happened that made me want to go back down to about 20 feet for a while. I figured I still had enough left in the doubles to take care of things. Eventually I noticed that it got a little bit harder to breathe, and I knew that meant I was getting pretty low on air. After about 10 breaths, each a little more "draggy" than the one before, I signalled my intent to surface and made a leisurely ascent. I was never out of air.

While that was happening, I thought of the people who insist that OOA incidents always come instantly and without warning, so you might not have a full breath for your ascent.

 

[scubadada]

Hi @boulderjohn

What was your cylinder pressure during this ^ episode?

 

[northernone]

Eventually I noticed that it got a little bit harder to breathe, and I knew that meant I was getting pretty low on air. After about 10 breaths, each a little more "draggy" than the one before, I signalled my intent to surface and made a leisurely ascent. I was never out of air.

That's why I love unbalanced regs. I won't dive a reg I haven't breathed on an "empty" tank to know how it will behave.

Some give no warning. Others a handful of breaths. I like the ones the give warning.

(A warning is only good if the diver is paying attention. And diver who run out of gas rarely are the most vigilant sort)

 

[boulderjohn]

My regs were balanced--the same ones I take to the bottom of that lake (280 feet, although not on that dive). I did not look at my SPG when it started to breathe hard, because I knew it would be close to zero. I had gas all the way to the top, but it must have been close to fumes at that point.

 

[scubadada]

I've never breathed my cylinder down to essentially zero and do not know what it feels like. I have been tempted to do this more than once. Lowest cylinder pressure I've had is around 170 psi, no noticeable increase in work of breathing

 

[northernone]

I've never breathed my cylinder down to essentially zero and do not know what it feels like. I have been tempted to do this more than once. Lowest cylinder pressure I've had is around 170 psi, no noticeable increase in work of breathing

Seems like the SPG needle needs to be on 0 for a few breaths before I can start to feel it.