Buoyancy question

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

maulotaur

Registered
Messages
15
Reaction score
8
Location
Central Ohio
# of dives
25 - 49
I have what may be a dumb question, but I am going to ask anyway. I have tried the search function, but my GoogleFoo is weak today. I either got 10,000 hits or 0. None of the hits were answering my question.

I just completed my OW checkout dives this past weekend. At one point, I swam over the top of another diver. When I did that, his exhalations seemed to mess with my buoyancy. I do not remember the instructor covering this or remember reading this in the book. It is possible that it is there, I just do not remember it.

Is this really a thing or was it a coincidence and it was just my novice-self needing a huge amount of practice in maintaining my buoyancy?

Thanks!
 
Air in the water makes the water less dense. Anyone who has shot rapids can attest to that phenomenon. However, as soon as the air passes you, it's density is restored. You might get a bit of weirdness, but you won't fall on the other diver.
 
Is it possible that as a new diver the experience of passing over another diver's exhaust distracted you and caused a fluctuation in your depth that led to you losing focus both mentally and physically?
 
Is it possible that as a new diver the experience of passing over another diver's exhaust distracted you and caused a fluctuation in your depth that led to you losing focus both mentally and physically?

Ray - Absolutely possible and that is what I thought it was. I was equating it to when you first learn to drive an auto. After some experience, some people can have children in the back seat without weaving all over the road.

I read this yesterday and wondered if in addition to me being new, that there was something else I didn't know about: Rude divers
 
For most people there is a tendency to inhale a bit more and exhale a bit less when something stressful happens. (Probably an instinctive throwback to breath holding)

This will mess with your buoyancy a bit especially when shallow.

It takes a while to get comfortable enough to not let minor things interfere with your breathing.

I don't like going over divers if I can help it, if they have an issue and do a Polaris then I'm not keen on going along for the ride.

The exception is when I have students and sit above and slightly behind them so they forget about my presence and I have better control if needed
 
Is it possible that as a new diver the experience of passing over another diver's exhaust distracted you and caused a fluctuation in your depth that led to you losing focus both mentally and physically?

I know that has happened to me. Can be really discombobulating.
 
I assumed it was me being new and not maintaining correctly. Then I read the bit in the "Rude divers" thread about messing with her buoyancy. Just wanted to check what way it was meant. It did not make sense to me that it would have an effect on me. I just need lots and lots of practice. :wink:
 
The diver exhalation bubbles can have some effect to "push" you upward in depth. If in enough mass and impacting on the center of your chest, you'll feel like you've gained some positively buoyancy. Usually it's not enough to really throw you off, unless you already don't have a good handle of buoyancy control.

My best guess has always been that's it's drag of the air bubbles against your wetsuit. Your body is a parachute catching the bubbles upwards force and it will have a slight effect on you. If you're at the top of your inhale you're already slightly positive buoyant the bubbles will add to that and send you on a very mild ascent.

My experience diving some aquarium exhibits with some massive air stones really confirmed this. If you swam through a huge bubble column, it would send you to the surface and you wouldn't be able to kick down against it.
 
The diver exhalation bubbles can have some effect to "push" you upward in depth. If in enough mass and impacting on the center of your chest, you'll feel like you've gained some positively buoyancy. Usually it's not enough to really throw you off, unless you already don't have a good handle of buoyancy control.

My best guess has always been that's it's drag of the air bubbles. Your body is a parachute catching the bubbles upwards force and it will have a slight effect on you. If you're at the top of your inhale you're already slightly positive buoyant the bubbles will add to that and send you on a very mild ascent.

My experience diving some aquarium exhibits with some massive air stones really confirmed this. If you swam through a huge bubble column, it would send you to the surface and you wouldn't be able to kick down against it.
Totally concur with @g1138 - I have had many similar experiences when monitoring a group of open water students from above them in both a pool or open water situations.
 
There is a dive site in Utah that is very popular for instruction. It includes a couple of PVC squares where the instructor can work with students. Sometimes more than one class works at once. I assure you I always feel a disruption when I am at a platform and a group passes below me. If they stay there a while, it is like being in a current.
 

Back
Top Bottom