Spare Air to Shoot Fish

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I know a guy who used to run a few spear fishing trips (on scuba) every year. Most of those dives were at 20 feet or less, yet he required all divers to carry spare air. I really never understood that.

Oh yeah, he did sell those things.:wink:

We don't sell them. I just don't care for the concept as opposed to proper training, experience and that good ol' buddy system. And, in the OP's scenario, all I could think of was lung over expansion. Scary thought.
 
As above, it is a bad idea. If you breath off it at 20' and hold your breath on the way to the surface, the air in your lungs will expand and you won't know it. Even a small amount of air trapped in the lungs can expand on ascent, rupturing the lung and causing life-threatening embolisms. There is a report of a death occurring when a person breathed off a scuba tank at the bottom of a pool and embolized on the 6' swim to the surface of the pool.
 
Everybpdy is welcome to their own opinion but the second time you ran out you could be a lot closer to the surface.

Running out of air is dangerous, especially for a freediver with a spare air, who has to figure out during an emergency, if inhaling or exhaling is "good" or bad", depending on where he got his last breath.

If you're going to freedive, freedive. If you're going to SCUBA dive, do that.

Planning a dive where you might or might not be out of air multiple times is just begging for a horrible death.

flots.
 
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As above, it is a bad idea. If you breath off it at 20' and hold your breath on the way to the surface, the air in your lungs will expand and you won't know it. Even a small amount of air trapped in the lungs can expand on ascent, rupturing the lung and causing life-threatening embolisms. There is a report of a death occurring when a person breathed off a scuba tank at the bottom of a pool and embolized on the 6' swim to the surface of the pool.

If you have the link for the pool incident, can you post it please?

I appreciate everyone's great advice and perspective.
 
As above, it is a bad idea. If you breath off it at 20' and hold your breath on the way to the surface, the air in your lungs will expand and you won't know it. Even a small amount of air trapped in the lungs can expand on ascent, rupturing the lung and causing life-threatening embolisms. There is a report of a death occurring when a person breathed off a scuba tank at the bottom of a pool and embolized on the 6' swim to the surface of the pool.

If you have the link for the pool incident, can you post it please?

I appreciate everyone's great advice and perspective.

I took a brief course on the hyperbaric chamber ending in a "dry dive" to 130'. The man who ran the course was a part of the hyperbaric unit and told some case studies. They had treated a woman who suffered an embolism when she panicked during her confined dives at the YMCA and stood up in the shallow end of the pool while breathing heavily due to the panic. She survived fortunately. I don't have a link as I understand this was several years ago, but I learned a lot about dive injuries in that class. It was very interesting.
 
I do and love both freediving and scuba diving, just not on the same day. I personally think that breathing at depth while freediving is not a good idea. I would just work on my fitness and technique. With a bit of practice you should be able to do a 40 foot dive with a minute bottom time if just moderately fit and using the correct technique. That is ample time for stalking a non suspecting fish.
Another thing I disagree with is spearing on scuba. Where I live it is illegal and in my opinion it should be.
 
First off, why are you not SCUBA diving to get the fish in the first place? Often the answer is that the bubbles scare away the fish. So, once you move to the Spare Air, you are now on SCUBA (albeit a very small and IMHO unless tank) and your are blowing bubbles. Remember according to Boyles Laws of Physics you cannot hold your breath once you take a breath underwater, you must keep the airway open. Translation, you are breathing in and out and making bubbles that are noisy and frighten the fish. Counterproductive and dangerous if you ask me. At 33 feet the spare air would give you approximately 1.5 to 3 minutes of air depending on your physical conditioning, temperature of the water, currents and work load. In SCUBA the deeper you go, quicker your air is used.

As others have said, for a breath hold diver to use compressed air on a free dive would be dangerous. The minute you take a breath while underwater, you are now diving by the laws of physics dealing with pressure and volume (Boyles Law) and the rules of SCUBA Diving and need to have that training. There are no SCUBA Police, but Darwin does clean out the gene pool from time to time. Taking a breath at depth on SCUBA and ascending only 4 feet is sufficient to potentially cause an over expansion injury, and that is not a good thing. Is the fish worth the risk to your health/life?
 
https://www.shearwater.com/products/swift/

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