Changes in Pressure from Swells

[Doc Intrepid]

Some of you dudes have waaaay too much time on your hands...

If the waves are high enough that they could mess around with your 10' deco stop, combine your 10' and 20' stops at 20', then move up to the surface reeeeeeaal slow.

No worries.

If the waves are high enough that they could impact your 20' deco stop, you shouldn't have gotten in the water to begin with.

 

[The Kraken]

Tell it, Doc !!!
Shout it out, Brother !!!

You're not going to have to worry about an embolism, you're going to have to worry about how you're going to get up the ladder with a broken leg!

the K

 

[Doc Intrepid]

Can I get an "Amen"?!

 

[gangrel441]

Ahhh...but the question wasn't concerned about getting bent. The question was about geting embolized. Based on the question asked, this probably needs to be answered in Myth-Busters fashion.

 

[mccabejc]

I suspect the issue is this:

Diver entering surf from the beach. Let's say waves/swells are peaking at 5 feet tall before they break. Diver ducks under 5 ft swell, and as swell passes over he takes a big drag on his regulator, then instinctively holds his breath. At this point he is at the equivalent of 5 feet deep, holding his breath. Wave passes over him, and as the bottom of the trough is above him his body has seen the ambient pressure going from 5 feet deep to 0 feet deep, while holding his breath.

If we assume the time from peak to trough is 5 seconds (actual is probably shorter than that), it's as if he had surfaced from 5 feet to 0 feet in 5 seconds while holding his breath. That's an equivalent ascent rate of 60 ft/min. No big deal, unless the wavelength was much shorter. Though I don't think the ascent rate would be the damaging factor here...

My guess is that if you held your breath, with full lungs, at 5 feet and popped to the surface like that you might be at high risk for emoblism. I sure as heck wouldn't want to try it. Which is why we were taught to have your snorkel, not your reg in your mouth when entering the surf... (the second important use for a snorkel )

My NAUI Master Diver manual says the following:

"Lung overpressurization can result from a pressure change as small as slightly over one meter, or about four feet".