Freediving after open circuit

[Deefstes]

Greetings peeps,

I was wondering about this the other day, hoping you guys can help. I remember reading somewhere (it could have been my dive computer's user's manual) that it is not advisable to do freediving shortly after scuba diving.

1. Does anyone know why this is not advisable?

2. I have snorkeled on the surface after some dives, whether to swim with a whaleshark or just to have another look around what's going on below while I'm waiting for other divers to surface. I've dived down to get a nice picture of a Whaleshark or to have a closer look at something but always only to about 5m or so, nothing exceptional. Was just wondering if that is risky as well and whether I should rather just stay on the surface?

 

[Cave Diver]

Greetings peeps,

I was wondering about this the other day, hoping you guys can help. I remember reading somewhere (it could have been my dive computer's user's manual) that it is not advisable to do freediving shortly after scuba diving.

1. Does anyone know why this is not advisable?

2. I have snorkeled on the surface after some dives, whether to swim with a whaleshark or just to have another look around what's going on below while I'm waiting for other divers to surface. I've dived down to get a nice picture of a Whaleshark or to have a closer look at something but always only to about 5m or so, nothing exceptional. Was just wondering if that is risky as well and whether I should rather just stay on the surface?

First off, if you recall from your basic open water class, the greatest pressure change occurs in the first 33 feet.

Freediving after you've already surfaced can cause bubbles that have already grown to shrink and pass through before growing again as you return to the surface.

Although I know a lot of people have done snorkelling and some shallow freediving after a dive, it seems risky enough that I personally wouldn't advise or participate in it.

 

[Deefstes]

Freediving after you've already surfaced can cause bubbles that have already grown to shrink and pass through before growing again as you return to the surface.

Thanks for the answer. Could you expound on this perhaps? What exactly does "pass through" mean? Also, if you refer to "bubbles that have already grown", does that refer to microbubbles? I thought the whole idea of making slow ascents and safety stops was to avoid bubbles from forming in the first place. Or are you saying that most divers (if not all divers) do end up with some amount of bubbles in their tissue after a dive?

PS - I have heard of microbubbles but know very little of it. Maybe if I did I would have better understood your answer.

 

[Crowley]

Here's a fairly involved (and rather technical and inconclusive) discussion on this forum:

http://www.scubaboard.com/forums/ask-dr-decompression/159-freediving-after-scuba-long.html

C

 

[jvilalta]

It might help to think of freediving after a dive as shaking the proverbial soda bottle once it has been opened...