Buoyancy Inverted

[stakanak]

I have found that even when I have achieved mean buoyancy, when I go inverted (which I really enjoy), I descend. I have paid attention to not moving my fins, keeping my breathing rate steady, etc. Whats the issue?
Good Diving

 

[Diver0001]

I'm not sure what you're saying. Are you saying tha you have a problem with turtling over while you descend?

R..

 

[Blue982]

I think he's having a problem descending when he turtles over. Just like regular buoyancy control but when you're head down feet up instead of horizontal.

If it's just a little bit, it could have to do with the fact that the buoyancy cell of your BC is lower and thus smaller than when you're horizontal (or vertical, whatever your default position is). That would make you slightly negative, especially if you're shallow.

Depending on your buoyancy skills, you may also be unconsciously kicking ever so slightly when horizontal to maintain position. If you continue to do this inverted, you might be kicking down a bit. If you don't you'll still be a little negative. Have a dive buddy check you out when inverted and see if you're kicking at all.

I've noticed this too. I usually just use my lungs, and don't stay upside-down for long. I exhaled once and hit my head, not my best moment.

 

[Diver Tim]

I'm guessing he means vertical, but inverted... That is to say: head down, fins up.

 

[TSandM]

I have noticed the exact same thing. I don't know if it has to do with a change in lung volume with posture, or if the buoyancy cell is lower when you invert and is therefore slightly compressed. It's not a big effect, but it's consistent and noticeable.

 

[LeadTurn_SD]

I have noticed the exact same thing. I don't know if it has to do with a change in lung volume with posture, or if the buoyancy cell is lower when you invert and is therefore slightly compressed. It's not a big effect, but it's consistent and noticeable.

1+

I do notice a slight buoyancy change when I go pure vertical, either head-up or head-down.

I'd guessed that is was the reduction in the total surface area presented (relative to gravity)... but I really don't know if this is correct.

I sure a Naval Architect will chime is soon and explain it

Best wishes.

 

[Blackwood]

I wonder if the OP is maybe kicking a little bit (possibly without knowing it) to maintain vertical position in the water.

 

[dwhthediver]

I have noticed the exact same thing. I don't know if it has to do with a change in lung volume with posture, or if the buoyancy cell is lower when you invert and is therefore slightly compressed. It's not a big effect, but it's consistent and noticeable.

+1
I could not agree more

 

[redacted]

If you are neutral in a normal swimming position, you should still be neutral and any other position; at least within a range that should be easily managed by controlling your breathing. You might try working on breathing control a bit more.

 

[Rhone Man]

My best guess would be a combination of things suggested here: bouyancy cell being slightly lower (and of course lungs slightly lower too), and less resistance to downward movement presented by the inverted profile.

This thread reminds of the good 'ole "swim down and then swim up" days before BCs were popular. Except that they weren't that good really.