Diving for 2 minutes to 20 feet or 10 feet and coming to the surface

[scubadude223]

Hi,

I have a question that was. Never fully answered in my diving days.

If one wanted to do a dive to 10 feet to find a shell or something and then swim to the surface can he do it safely according to the tables

how many of these can safely be done.

 

[Wookie]

I would freedive that profile, and do it all day every day for infinity. The danger of scuba is lung expansion or embolism, not DCS.

 

[scubadude223]

Thanks,

reason on being I could not find information on it.

I usualy snorkel for 5minutes, scuba for 30 seconds and repeat the same thing for over 2 hours.

I wasent sure sure if there were any special considerations.

Thanks again so much

 

[Wookie]

Why the scuba? Sounds like a breathhold course is in order. You are doing it (IMHO) in about as dangerous way risking lung overexpansion as you possibly can.

 

[scubadude223]

That is what I am trying to figure out.

What at are my risks. I don't hold my breath through the dive.

Why hey are my risks for lung expansion greater?

 

[Bob DBF]

Why hey are my risks for lung expansion greater?

Because you are breathing air under pressure and you could possibly surface with your airway closed.

I don't see a problem with your dives, but I exhale slightly even when free diving. I do agree with Wookie, I'd just free dive that profile rather than gearing up, I'm lazy.


Bob

 

[boulderjohn]

Why hey are my risks for lung expansion greater?

If you are breath hold diving, when you descend your lungs get smaller than when you started, and when you ascend, they expand to their original size. They cannot get bigger than they started. You will not have a lung overexpansion injury.

When you descend on scuba, when you inhale, the compressed gas fills your lungs, keeping them the same size as on the surface, but with more (compressed) air in them than they can hold on the surface. If you hold your breath on ascent, the expanding air can damage the lungs.

 

[Basking Ridge Diver]

If you are certified OW - you may remember that the first ATA down to 33 feet is the greatest differential in pressure - twice the ATA from the surface. Since you are in this range the same principles apply and you want to go the slowest ascent in your last 20 or 10 feet in your case to avoid lung expansion.

 

[Wookie]

If you are breath hold diving, when you descend your lungs get smaller than when you started, and when you ascend, they expand to their original size. They cannot get bigger than they started. You will not have a lung overexpansion injury.

When you descend on scuba, when you inhale, the compressed gas fills your lungs, keeping them the same size as on the surface, but with more (compressed) air in them than they can hold on the surface. If you hold your breath on ascent, the expanding air can damage the lungs.

I agree with all of this, but I was more concerned with you doing it in the top 10 or 20 feet. The greatest risk for lung overexpansion is nearer the top of the water column than down deeper. ANd I'm concerned with the repetitiveness of it all. If you jump in and do a 10 or 20 foot dive, the risks aren't that great. If you do a hundred, even a small risk multiplied by 100 are 100 times more likely than a small risk.

 

[scubadude223]

At no point am I holding my breath.

I I just wanted to know if a 30 second dive on standard scuba was ok.

I I would be breathing at the surface and underwater. Being that the dives are shorter would there be a risk.

The 30 second dives are using standard scuba with no breath holding at all.


Thanhs again