Microbubbles and Shore Diving

[bwerb]

I'm going to have to totally re-think the Wed. night dive procedures. The old, into the water, dive, surface, lug gear back to car and split before immediately going to bed now doesn't seem like such a great idea...time to build-in some surface rest and relaxation.

 

[Grajan]

But I am not getting a clear indication of how long one should rest for.

I realise there are a lot of variables but is there some rule of thumb?

 

[Uncle Pug]

Dr Deco once bubbled...
If that was not possible, then I would

• limit my final dive to a time much less than the NDL

• 
  Sometimes even that isn't enough having conducted an actual experiment a week or so ago.
  
  Max depth 47' total time 26 minutes using EAN32.
  
  1/4 mile hike down to the beach carrying doubles.
  Current dive on the highest exchange of the year.
  Vigorous swim from the last handhold across current.
  Direct (read *really fast*) ascent from 14' to surface.
  Sprint across surface current to shore.
  Hike back up beach to trail.
  1/4 mile hike back up to the parking lot.
  
  A long surface interval was followed by two very modest dives at different easy access site and well within anyones NDL (the last of which had plenty of shallow float time.)
  
  I felt hammered for two days after this... and didn't dive the rest of the week. It wasn't the last two dives... it was the first dive that did it.

 

[Grajan]

You just need to act your age......

After all that the last thing I would need to worry about is a hit...

 

[Dr Deco]

Dear Readers:

Bubble Formation/Growth and Supersaturation

Mike Ferrara brought up a good aspect of the bubble formation/growth question and supersaturation. During the construction of the large bridges in St Louis and Brooklyn, it was noted that the position of the airlock with respect to the ascent ladder was important with regard to Caisson Workers’ Disease (“the bends”).

If the “sandhogs” climbed up the ladder and then entered the air lock, the risk of “the bends” was less than if they had entered the lock and then climbed up the ladder.

In physics, that would be a “path dependent” process. In the first case(climb and then exit), one can see that the workers were generating microbubbles but they were not supersaturated. [Yes, they were saturated but not supersaturated. In the second case (exit and then climb), the workers were generating microbubbles in supersaturated tissues. This resulted in a very harmful procedure. To obviate this, an elevator was substituted for the ladder thus removing climbing altogether.

Take home Lesson
The beach diver should clearly climb the hill first and then decompress.

Certainly this is not possible. The other course of action is to wait, off gas and then climb.

Dr Deco :doctor:

Please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[scubasean]

Uncle Pug once bubbled...
If you can, make use of the World's Largest Waterbed and restawhile.

I like this idea...Sounds comfy....

More than one reason to have a nice BC...(!!)

--Sean

 

[Charlie99]

Dr Deco once bubbled...
The beach diver should clearly climb the hill first and then decompress.

Certainly this is not possible. The other course of action is to wait, off gas and then climb.

What sort of offgassing period makes sense?

Obviously longer is better, but how long should you wait in order to get most of the benefit. 1 hour?? More??

Charlie

 

[Braunbehrens]

Stone once bubbled...


I am a true believer in using an anchor ball.

Me too. Unfortunately, sometimes it doesn't work, and I don't have a winch.

 

[Braunbehrens]

Dr Deco once bubbled...
Dear Readers:
and aid off gassing by moving my arms and legs; this would promote blood flow and off gassing, [*] perform similar movements on the beach and definitely not sleep since this would reduce blood flow to its lowest possible level. [/list]
Dr Deco :doctor:
Please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

Wasn't there some recent research suggesting that small amounts of exercise, such as light finning, were actually not indicated and could cause more harm than good?

 

[Diver0001]

Dr Deco once bubbled...
Dear Readers:

Post-Dive Exercise and Microbubbles

If there is any sure way to increase the risk of DCS following a dive, heavy exercise is the way to go. Dive tables are never tested with this post-dive activity. Possibly they should be, but that would decrease allowed bottom time considerably and penalize the vast majority of recreational divers who do not perform work such as hauling their gear.

I've heard you repeat same many times but surely we should have some kind of recommendation. We have a recommendation for flying. Is exercise after diving so much harder?

<just kicking up a little dust>

R..