Buoyancy

[BRT]

This is a great demonstration on why to use the least amount of weight possible. The less air you have in your BC to maintain neutral buoyancy, the less there is to compress as you dive deeper. I rarely use any exposure protection and I rarely have any air in my BC. Ergo, my depth rarely impacts my buoyancy. I can descend to 130fsw and back up to the surface using only my breathing.

So you just allow yourself to be heavy at the start and compensate with your lungs or swim up?

 

[wetb4igetinthewater]

So you just allow yourself to be heavy at the start and compensate with your lungs or swim up?

Following Pete's comments, I spent a pool session to get myself able to sink to the bottom of the pool and rise back to the surface using only my lungs.

Can't do that in the open water like Pete with all my exposure protection. But it is something I would like to play with in warmer locations.

 

[BRT]

Of course you can do that with just your lungs, but I much prefer to offset tank air with my BCD.

 

[JackD342]

So, regarding divers who "swim" in a vertical (or semi-vertical) position in the water and rely on finning to maintain their position in the water column, I fully agree with all of the points that have been made regarding air consumption, stirring up the bottom, damaging reefs, etc.

But I want to add one more (possibly most important) thought on the topic...
I believe that the diver that needs to be kicking/finning/sculling to keep from sinking, (or routinely uses that method as their default mode) is very likely to be a danger to themselves when diving on a wall with the bottom out of reach and/or out of sight. One moment of distraction or relaxation and they are on their way down, possibly without realizing of it for quite some time depending on other visual references available.

I absolutely teach my students that if you feel you will sink if you stop kicking, then you are NOT yet in control of your neutral buoyancy.

 

[wetb4igetinthewater]

But I want to add one more (possibly most important) thought on the topic...
I believe that the diver that needs to be kicking/finning/sculling to keep from sinking, (or routinely uses that method as their default mode) is very likely to be a danger to themselves when diving on a wall with the bottom out of reach and/or out of sight. One moment of distraction or relaxation and they are on their way down, possibly without realizing of it for quite some time depending on other visual references available.

That's an extremely important point. I can visualize that happening and the terror of the diver when they realize how far down they may have gone.

 

[The Chairman]

So you just allow yourself to be heavy at the start and compensate with your lungs or swim up?

No. Way no. Using my breathing, I stay neutral during the whole dive. Neutral. There's always a little air left in your BC to remove if I need to. Usually, adjust my breathing is sufficient.

I see the BCD as a gross adjustment and my breath as the fine tune for my dive. I descend in this manner if I'm wearing a bladder: (sorry, but this is uber detailed)

• On the surface, with a full, or partially full BCD, I float vertically in the water
• Lift my inflator/deflator high out of the water with my left hand
• I depress the deflator
• I keep the deflator depressed until I feel the water just cover my head (awash)
  • One smooth deflation
    • No pumping of the deflator button
  • Releasing is a matter of timing, so adjust as necessary on subsequent dives
• Do a super exhale
• Get into the scuba position (horizontal)
• Adjust my descent rate using my profile and angle of attack
  • Horizontal with limbs extended for the slowest descent
  • Head way down with arms and legs streamlined for the fastest descent
  • I may flutter kick to get there faster
• Inhale when needed
  • This will stop your descent
  • Exhalation resumes your descent
• A sharp inhale a few feet from the bottom stops my descent immediately and completely
  • If you're about to hit the bottom, arrest your descent with a single finger on something hard and dead
  • You won't need this once you get the hang of it all
• Establish neutral buoyancy
  • Establish a hover
    • No kicking
  • Add or remove tiny amounts of air and breathe once or twice to recheck
  • Repeat until I'm comfortable
  • I take my time and won't rush this process!!!
• From here on out, I adjust my depth using my breathing
• To ascend horizontally, I take a super breath, being sure to keep that glottis open
  • I want to feel/hear/see bubbles coming from my reg as I ascend due to Boyles' Law.
• At my safety stop I exhale to stop and then let out any air that might be in my BCD, usually a quart or so and get vertical.
  • This allows me to recheck my buoyancy on every dive
  • I casually spin looking for boat traffic, other divers, fish and fun...
    
  • Sometimes, this is the best part of the dive!
• On my final ascent, I take another spin, barely add air to my lungs while keeping that glottis open, and slowly work my way to the surface.
  • Air allowing, my minimum stop is 5 minutes
  • Air allowing, I usually begin when I see the last diver just start to get on the ladder
• Once on the surface, I inflate my bladder (if I have one) and grab the tag line
• On the tag line, I remove my fins before I get to the ladder
  • Fins go on either wrist
    • I don't give them to any crew
    • In case I fall back into the ocean

I absolutely teach my students that if you feel you will sink if you stop kicking, then you are NOT yet in control of your neutral buoyancy.

Amen, brother, amen!!! Control makes and keeps you safe. Having to continually add and subtract air to achieve neutral buoyancy is too much mental work, especially when you're narced. I don't let my students out of the pool until they can accomplish this super easy task.

 

[BRT]

No. Way no. Using my breathing, I stay neutral during the whole dive. Neutral. There's always a little air left in your BC to remove if I need to. Usually, adjust my breathing is sufficient.

I see the BCD as a gross adjustment and my breath as the fine tune for my dive. I descend in this manner if I'm wearing a bladder: (sorry, but this is uber detailed)

• On the surface, with a full, or partially full BCD, I float vertically in the water
• Lift my inflator/deflator high out of the water with my left hand
• I depress the deflator
• I keep the deflator depressed until I feel the water just cover my head (awash)
  • One smooth deflation
    • No pumping of the deflator button
  • Releasing is a matter of timing, so adjust as necessary on subsequent dives
• Do a super exhale
• Get into the scuba position (horizontal)
• Adjust my descent rate using my profile and angle of attack
  • Horizontal with limbs extended for the slowest descent
  • Head way down with arms and legs streamlined for the fastest descent
  • I may flutter kick to get there faster
• Inhale when needed
  • This will stop your descent
  • Exhalation resumes your descent
• A sharp inhale a few feet from the bottom stops my descent immediately and completely
  • If you're about to hit the bottom, arrest your descent with a single finger on something hard and dead
  • You won't need this once you get the hang of it all
• Establish neutral buoyancy
  • Establish a hover
    • No kicking
  • Add or remove tiny amounts of air and breathe once or twice to recheck
  • Repeat until I'm comfortable
  • I take my time and won't rush this process!!!
• From here on out, I adjust my depth using my breathing
• To ascend horizontally, I take a super breath, being sure to keep that glottis open
  • I want to feel/hear/see bubbles coming from my reg as I ascend due to Boyles' Law.
• At my safety stop I exhale to stop and then let out any air that might be in my BCD, usually a quart or so and get vertical.
  • This allows me to recheck my buoyancy on every dive
  • I casually spin looking for boat traffic, other divers, fish and fun...
    
  • Sometimes, this is the best part of the dive!
• On my final ascent, I take another spin, barely add air to my lungs while keeping that glottis open, and slowly work my way to the surface.
  • Air allowing, my minimum stop is 5 minutes
  • Air allowing, I usually begin when I see the last diver just start to get on the ladder
• Once on the surface, I inflate my bladder (if I have one) and grab the tag line
• On the tag line, I remove my fins before I get to the ladder
  • Fins go on either wrist
    • I don't give them to any crew
    • In case I fall back into the ocean

Amen, brother, amen!!! Control makes and keeps you safe. Having to continually add and subtract air to achieve neutral buoyancy is too much mental work, especially when you're narced. I don't let my students out of the pool until they can accomplish this super easy task.

So you compensate with your lungs instead of the BCD.

 

[The Chairman]

So you compensate with your lungs instead of the BCD.

If I have a bladder, then I use both. If I dive without a bladder, then just my lungs. They broke my bladder in the Philippines and I just dove without it. No one complained about my buoyancy except for one guy. He was pissed that mine was better than his and he had the use of a bladder! Go figure.

Use all your tools. My lungs are as much of a tool in diving as is any bladder. I use the bladder for coarse adjustments and my lungs for fine adjustments. This largely goes out the window when I'm on my rebreather, but not completely. In that case, a super breath will trigger my ADV (Automatic Diluent Valve) and add air. Of course, I can always exhale through my nose to vent any excess in my breathing loop. However, I have to add/subtract from my BC all the time on a rebreather which I rarely have to do while on OC.

This is the way I dive. This is how I teach it. If anyone doesn't understand or like it, then they are free to dive in any manner they want. I get compliments on my students' trim and buoyancy all the time because it's so easy that they look good from the start. In any event, just be safe and in control however you do it.

 

[wetb4igetinthewater]

No one complained about my buoyancy except for one guy. He was pissed that mine was better than his and he had the use of a bladder! Go figure

That’s a mindset I’ll never understand. He lost an opportunity to learn from you. Only requirement was to have an open mind and set aside the ego. this just isn’t about buoyancy....

 

[BRT]

If I have a bladder, then I use both. If I dive without a bladder, then just my lungs. They broke my bladder in the Philippines and I just dove without it. No one complained about my buoyancy except for one guy. He was pissed that mine was better than his and he had the use of a bladder! Go figure.

Use all your tools. My lungs are as much of a tool in diving as is any bladder. I use the bladder for coarse adjustments and my lungs for fine adjustments. This largely goes out the window when I'm on my rebreather, but not completely. In that case, a super breath will trigger my ADV (Automatic Diluent Valve) and add air. Of course, I can always exhale through my nose to vent any excess in my breathing loop. However, I have to add/subtract from my BC all the time on a rebreather which I rarely have to do while on OC.

This is the way I dive. This is how I teach it. If anyone doesn't understand or like it, then they are free to dive in any manner they want. I get compliments on my students' trim and buoyancy all the time because it's so easy that they look good from the start. In any event, just be safe and in control however you do it.

You said "I rarely have any air in my BC"

Reality is I dive like you do. Using my BCD and my lungs for compensation. It is just too much work to compensate for the buoyancy swing full to empty using only lungs. I dive with people who wear no BCD's. In their working environment, swimming fast after fish, they use less air than I do. Diving on the wall in Cozumel they use more air than I do.