Snorkel between Dives?

[SYDSIDE]

Hi folks,

A simple (and possibly dumb) question from an OW newbie:

Is there any reason (ie DCS, microbubble build-up, etc) that one should not snorkel and freedive (down to 5-10m) between the normal the periodic SCUBA dives during a day?

I just need to know because my wife and I are going on a Thai liveaboard in February and she does not dive. I would like to spend some time snorkeling with her between my dives.

Thanks for any advice

 

[O-ring]

SYDSIDE once bubbled...
Hi folks,

A simple (and possibly dumb) question from an OW newbie:

Is there any reason (ie DCS, microbubble build-up, etc) that one should not snorkel and freedive (down to 5-10m) between the normal the periodic SCUBA dives during a day?

I just need to know because my wife and I are going on a Thai liveaboard in February and she does not dive. I would like to spend some time snorkeling with her between my dives.

Thanks for any advice

Snorkeling is ok, but freediving between dives is a no-no. Some DM just got bent doing that recently...up to you, but I wouldn't do it..

http://www.scubaboard.com/showthread.php?s=&threadid=16812&highlight=freediving

 

[Big-t-2538]

What's that....but seriously, if you want to snorkel....go right ahead. O-ring linked the post that speaks of a recent tragedy stemming from free-diving between SCUBA dives. You are recompressing those nitrogen bubbles and allowing them to move around more freely in your system (i'm not a medical guy so I'm vague) which can cause some damage.

I wouldn't suggest free-diving to any depth...the greatest pressure differential is in the first 30 feet of diving...

 

[Genesis]

is a MAJOR no-no.

The problem is that most of us will bubble somewhat in the venous (low-pressure return) side of our circulation. This is usually ok as your lungs are a pretty good bubble filter and will keep those bubbles from getting into the arterial side of your circulation where they can hose you.

If you free dive you risk compressing those bubbles enough so they can pass the capillary bed - effectively giving you a PFO or "shunt". Now you come back up from your freedive (it takes about 3 minutes for your blood to make a complete "circuit") with the bubbles on the WRONG SIDE of your circulation! Not good! That's a really good way to take a Type II (the kind you DON'T want!) DCS hit.

Snorkeling on the surface is fine. If you're going to go back down then do it right - do it on scuba, where you can sit down there long enough for the gas you recompress to go back into solution and into your tissues, then do your nice, slow ascent again so that its all again on the venous side of the circulation IF you bubble.

 

[Uncle Pug]

snorkeling might be OK... free diving might not be OK.

Homemade PFO test:
1) Years ago after diving the backside of Molokini at 100' I spent the SI freediving inside to 40' with plenty of valsalvas to check for the PFO or pulmonary shunt.

Homemade Micro Bubble generation test:
2) Even more years ago after two dives on a wreck at 75' in current (and past the Navy tables' NDL) I did a vigorous 300 yard swim back to the dive boat to check Dr. Deco's micro-bubble seed ideas.

***This was way before I knew about PFOs, pulmonary shunting or Micro Bubbles and obviously God was looking out for me... I have a friend who ended up paralyzed floating on the surface after a 60' bounce dive to retrieve something following his first dive.***

So you might be OK snorkeling as long as you don't swim too vigorously and generate bubble seeds.

You might even be OK free diving.... or not.

I wouldn't do it again.

 

[AllenG]

Are any of our venerable diving docs able to opine on how long a surface interval might be sufficient before free diving?

I've always done free-diving between dives or at the end of the day. While I apparently have been lucky enough to avoid any problems, the information on this thread and the cross-referenced threads was enough to make me re-think this activity.

I am wondering if one might be able to fashion a rule of thumb (from dive tables or the SI information on one's computer) to identify a reasonable SI before one might safely engage in free diving?

 

[joens]

I would not want to guess as far as how long to wait .there is an article on the general subject here. www.wkpp.org/articles/Decompression/bubble_formation_and_elimination.htm
joens

 

[joens]

in the article GI said wait 4 hours.
joens

 

[joens]

another article slightly more specific.
www.wkpp.org/articles/Decompression/why_we_do_not_bounce_dive_after_diving.htm
joens

 

[Iguana Don]

Found in the Dr.Deco Forum.

If I rember correctly, any strenious activity should be avoided during the "off gassing" period.

That would include free diving AND snorkeling.