Mixing SCUBA and freediving?

[nivram]

Whats everyones feeling on mixing scuba and freediving. I know freediving after scuba is suppose to be bad. HOw about freediving prior to scuba? Or mixing it with shallow depth diving?

I am suppose to go lobstering this weekend and the family wants me to scuba. We will be in about 15 to 20 feet of water. This isn't very deep and i've been on hookah in this depth upto 30' bounching off the bottom and to the surface just fine.

 

[spectrum]

I've had the same question, hopefully more responses surface. As long as the dive was in a comparable depth I would think the consequences would be slim since the NDL would be way up there but there's a lot more to blood gas science than I know and a bunch nobody understands yet.

Pete

 

[Gidds]

I think the concern about free diving after scuba is related to the "no strenuos exercise" concern. Lobstering sounds fairly strenuos as opposed to just swimming around looking at things.

 

[Firebrand]

I think the concern about free diving after scuba is related to the "no strenuos exercise" concern. Lobstering sounds fairly strenuos as opposed to just swimming around looking at things.

It depends on where you're lobstering. If you're in the Keys, then there are plenty of places you can hold your breath and free dive between 8 and 15 fsw to get lobster without too much exertion. Especially if you use a weight belt with 5 pounds to descend. I've watched my Dad and older brother dive in a location that was shallow (20 fsw) and then hop in the boat, remove scuba gear and 20 minutes later begin free diving again. Neither one of them had any problems either. Of course, they didn't dive deep. I would avoid a dive on the Spiegel Grove, followed by free diving for lobster. However, if you dive fairly shallow for lobster, then free dive for lobster, there shouldn't be a problem.

 

[nivram]

It depends on where you're lobstering. If you're in the Keys, then there are plenty of places you can hold your breath and free dive between 8 and 15 fsw to get lobster without too much exertion. Especially if you use a weight belt with 5 pounds to descend. I've watched my Dad and older brother dive in a location that was shallow (20 fsw) and then hop in the boat, remove scuba gear and 20 minutes later begin free diving again. Neither one of them had any problems either. Of course, they didn't dive deep. I would avoid a dive on the Spiegel Grove, followed by free diving for lobster. However, if you dive fairly shallow for lobster, then free dive for lobster, there shouldn't be a problem.

That's what I was thinking. Since I will be shallow on scuba. I didn't feel there would be a problem. I bought a new dive computer. But I am sure with it being shallow and if I were to throw in freediving. It was going to probably go crazy. But I am told we will mostly be in 15fsw. It almost doesn't seem worth it to scuba. But I would like to test out my new gear. We will be in the Keys.

 

[freediver]

The concern is likely the fact that any activity may interfere with your elimination of nitrogen and thus may alter your position on a dive table for subsequent dive considerations. Also remember, any apneic state you put yourself into may increase your air consumption on scuba. Negligible? Maybe, but worth consideration.

 

[DA Aquamaster]

How you feel about it probably also depends on what decompression theory you adhere to.

I would suspect that adherants of gradient factor models and variable permeability models may have issues with it as it could potentially create nuclei for bubble formation. In that case, freediving before diving would be a bad idea.

 

[ericrd]

some things you want to consider when free diving AFTER scuba diving:

- you are repressurizing your body, on & off, while you free dive. It s like the analogy with the coke bottle - shaking it - while you are off gassing, you repressurize, then brutally depressurizing... (remember that when free diving, your chest and stomach get compressed, and the pressure in your lungs will increase - not hugely, but will)

- RDP and computers are considering that you are constantly breathing air. If you hold your breath repetitively, you will desaturate differently from their model, and any successive dive cant be modeled by these (tables or computers)

of course, it isnt a DCI guaranteed -but can cause some problems.

eric

I've had the same question, hopefully more responses surface. As
long as the dive was in a comparable depth I would think the consequences would be slim since the NDL would be way up there but there's a lot more to blood gas science than I know and a bunch nobody understands yet.

Pete

 

[kidspot]

and remember that if wearing your computer while freediving, for a depth gauge, it may lock you out for 24 hours due to an ascent violation...

 

[WaterDawg]

Its not just the exertion but the risk of compressing bubbles to a size where they can by pass the lung filter and make their way into the arterial side and as you ascend decompress and as a result get bigger again but now in a part of your body that might cause problems...like the brain.