Divers: Is there a cross between a SCUBA and a freediving setup?

[911paramedic]

OK, I am a master scuba instructor. (seriously)

No is your answer, that would not work for many reasons. Hold your breath for 1.5 min? OK, but after doing that you will gasp and take several deep breaths to compensate for the O2 shortage, that's just physiology. BTW, the number one rule of breathing (<--key word) compressed air is you NEVER HOLD YOUR BREATH.The only thing near what you are talking about is Snuba, where there is compressed air on the surface and you are tethered with a hose. (think commercial diver without all the gear.)

If you hold your breath while breathing compressed air you are asking for trouble. The depths you would be diving would probably be in the 30' depth area, which are the most dangerous as volumes double in that first ~33'. (I think it's 0.45psi per foot, in saltwater) Imagine if you are in 10'swells and you are right under one when you take a deep breath at 10'. While the swell is over you you are now at 20' and don't even know it, as it passes you are immediately back at 10', a huge pressure change quickly. That's why I teach my divers to take medium breaths and not filling their lungs up all the way when doing beach entries and swimming out under waves and swells.

What you want to do would be dangerous, not to mention you would need to be certified to by compressed air...even a pony bottle. Take a scuba class and just go scuba diving, you can stay down for an hour easily at shallower depths and it's very relaxing.

 

[Gooberlx2]

Originally posted by: AUMM

Originally posted by: fuzzybabybunny
I'm getting conflicting info from daveymark and swimscubasteve... I think...

ok, ok

I use a pony bottle:

Descent: Take a deep breath, descend.

Arrival: Take half deep breaths, holding breath for 45 seconds at a time or so. Nice and easy, not taking deep deep breaths or anything. When I'm diving, I don't use any weights or anything, and without kicking, if I have a half deep breath, I actually *sink*. With an absolute lungs bursting full breath I tend to float up very very slowly, probably a foot a second. Methinks with the tank and extra gear I would be more inclined to sink down instead of float on a full breath.

Ascent: Exhale, and take normal breaths until I'm at the surface. Nice and easy.

Your lungs aren't the only space that holds air in your body. Your tissue and body fluids etc, hold air which will expand as well. When you are scuba diving, you often have to make a safety stop at 15 ft deep for like 5 mins or so (i forget exactly) in order to make sure all your air has equalized.

Ding ding ding! This is the correct answer! Catastrophically blowing out your lungs isn't going to be the big issue, since you can usually prevent that. There're always going to be micro ruptures in your alveoli, even with normal scuba divers ascending at proper rates with proper safety stops. The issues with "free-scuba diving" would be that you won't have the oxygen available to you to ascend safely. As a result the nitrogen that's leeched in to your tissues will bubble due to the pressure differences, because you're ascending at a rate that they blood stream can't remove the nitrogen. To make matters worse, since you're holding your breath, there's no way for your body to expel the nitrogen, which is normally done during gas exhange in your lungs when you breath. The bubbling causes immense pain and possible circulatory blockages. This is called getting bent. Extreme cases of the bends can cause strokes, pulmonary imbelisms, and other life threatening conditions.

 

[swimscubasteve]

Originally posted by: 911paramedic
OK, I am a master scuba instructor. (seriously)

No is your answer, that would not work for many reasons. Hold your breath for 1.5 min? OK, but after doing that you will gasp and take several deep breaths to compensate for the O2 shortage, that's just physiology. BTW, the number one rule of breathing (<--key word) compressed air is you NEVER HOLD YOUR BREATH.The only thing near what you are talking about is Snuba, where there is compressed air on the surface and you are tethered with a hose. (think commercial diver without all the gear.)

If you hold your breath while breathing compressed air you are asking for trouble. The depths you would be diving would probably be in the 30' depth area, which are the most dangerous as volumes double in that first ~33'. (I think it's 0.45psi per foot, in saltwater) Imagine if you are in 10'swells and you are right under one when you take a deep breath at 10'. While the swell is over you you are now at 20' and don't even know it, as it passes you are immediately back at 10', a huge pressure change quickly. That's why I teach my divers to take medium breaths and not filling their lungs up all the way when doing beach entries and swimming out under waves and swells.

What you want to do would be dangerous, not to mention you would need to be certified to by compressed air...even a pony bottle. Take a scuba class and just go scuba diving, you can stay down for an hour easily at shallower depths and it's very relaxing.

I don't know if decompression is really an issue here. 5 minutes at 65' probably wouldn't even require a safety stop if one were using Navy tables. Lung embolisms are also fairly easy to avoid.

I wouldn't recommend that they try this without proper supervision but it doesn't seem all that dangerous to go fool around with a pony bottle.

 

[uberman]

You might want to add to the no breatholding, is do not take full breaths while on scuba. Always leave a little space in your lungs for expansion. I've found good deals on name brand equipment here.

[http://www.leisurepro.com/]

 

[uberman]

Originally posted by: swimscubasteve
what's wrong with getting scuba certified?

You need to be certified. This is my opinion on selecting a class.

Regarding the scuba class. I'd look for a class that wasn't connected to a dive shop. Look for a class at a college, a parks and recreation department, someplace where making money is not their objective. I've been diving for over 30 years and 600 dives. I've watched the industry evolve. It used to be an unusual sport, but now its mainstream. Shops are businesses that are in business to make money. They want to sell you things. That means courses and equipment. It used to be that you only had basic diver certification. In the 1980s there was a push to teach all these classes. Shops make money selling classes. They make better money selling you equipment. An instructor who teaches you through a shop would likely find it difficult to recomend you purchase superior equipment not available at that shop. I've dove with instructors and commercial divers. One guy, an instructor told me to just keep diving, you don't need any classes. This was in response to my inquiry if I should try some new classes. I've had friends who've taken classes through shops and complain the instruction was terrible. Try to find instruction where money is not their primary motive for teaching you.
I like cold water diving best. Its what I grew up with. Yes, I do cuss when I put on a wetsuit and question, "Am I doing this for fun?" I know all the critters in the cold water so theres no surprises. I stick my head in caves in the tropics and I get many surprises. I spearfish and the fish move slower and are easier targets in cold water.
You don't need a lot of courses, but you do need to master the basics. Learn, buddy up, seek out some dive clubs and get some experience.
Do not buy a used wet suit. It is true that the neoprene loses its insulating efficiency from the day it rolled off the manufacturing line. I give a wetsuit 2 to 3 years tops. Its important to be warm.
I've bought great house brand wetsuits from Berry's Scuba. They are now defunct. I recently bought a house brand wet suit from Joe Diver. It is cheap crap.

 

[uberman]

Is there a cross between a SCUBA and a freediving setup?

Yes, a hookah rig. There are inner tube like floats that have compressors on them and feed you air by lines to a second stage mouthpiece. No more trips to the dive shop for tank fills. I used to use a set of twin 50s (tanks) with 40 feet of hose extending from the first stage of the regulator to the second. This was handy when working on boats in harbors.

 

[AndrewR]

Originally posted by: uberman
You might want to add to the no breatholding, is do not take full breaths while on scuba. Always leave a little space in your lungs for expansion. I've found good deals on name brand equipment here.

[http://www.leisurepro.com/]

Just a word of warning that Leisure Pro sells a lot of grey market gear, which means that it doesn't come with a warranty (you might be able to get warranty service in the country of origin, but unlikely!). They have great prices, but there is some risk.

Wow, I miss diving!

 

[Fayd]

i'm a certified open water diver (the first scuba certification)

i'm not gonna reiterate the problems of your idea. suffice to say, it's a bad idea.

anyways, i suggest getting scuba certified. if you get it through a dive shop (i think it's a good idea...) you're looking at maybe 100 bucks for the certification, 50 bucks for the gear rental, and you're good to go.

i'd suggest doing it that way, before going off and spending 1000 bucks on your own scuba setup and then finding out you dont like the sport.

i'd also suggest doing it that way, because it's the cheapest safest option.

 

[DrPizza]

Originally posted by: Fayd
i'm a certified open water diver (the first scuba certification)

i'm not gonna reiterate the problems of your idea. suffice to say, it's a bad idea.

anyways, i suggest getting scuba certified. if you get it through a dive shop (i think it's a good idea...) you're looking at maybe 100 bucks for the certification, 50 bucks for the gear rental, and you're good to go.

i'd suggest doing it that way, before going off and spending 1000 bucks on your own scuba setup and then finding out you dont like the sport.

i'd also suggest doing it that way, because it's the cheapest safest option.

Wow. 100 bucks through a dive shop would be dirt cheap. I can't recall exactly what I paid, but I think it was in the neighborhood of $400-$500 when I got my certification. This included a lot of water time; first in a pool, then in open water (an old quarry - very cool place: Bainbridge, PA) In my opinion, there's no way anyone's going to be competent enough not to hurt themselves with just one session in the water. Some of the skills, especially ascent rate, take quite a bit of practice.

 

[Fayd]

Originally posted by: DrPizza

Originally posted by: Fayd
i'm a certified open water diver (the first scuba certification)

i'm not gonna reiterate the problems of your idea. suffice to say, it's a bad idea.

anyways, i suggest getting scuba certified. if you get it through a dive shop (i think it's a good idea...) you're looking at maybe 100 bucks for the certification, 50 bucks for the gear rental, and you're good to go.

i'd suggest doing it that way, before going off and spending 1000 bucks on your own scuba setup and then finding out you dont like the sport.

i'd also suggest doing it that way, because it's the cheapest safest option.

Wow. 100 bucks through a dive shop would be dirt cheap. I can't recall exactly what I paid, but I think it was in the neighborhood of $400-$500 when I got my certification. This included a lot of water time; first in a pool, then in open water (an old quarry - very cool place: Bainbridge, PA) In my opinion, there's no way anyone's going to be competent enough not to hurt themselves with just one session in the water. Some of the skills, especially ascent rate, take quite a bit of practice.

i found some kind of deal where i got the owd cert for 75 bucks, not including rental. that included classes, pool time, and beach dive. the dive boat cost an additional x number of dollars, but it wasnt too bad. i just cant remember. somewhere in the area of 40 bucks.

EDIT: this was through sportmart, with PADI certs in San Diego.

btw, OWD cert requires several dives. 2 beach dives, and 2 dive boat dives. as well as enough pool time to figure out everything.

 

[911paramedic]

Originally posted by: swimscubasteve

Originally posted by: 911paramedic
OK, I am a master scuba instructor. (seriously)

No is your answer, that would not work for many reasons. Hold your breath for 1.5 min? OK, but after doing that you will gasp and take several deep breaths to compensate for the O2 shortage, that's just physiology. BTW, the number one rule of breathing (<--key word) compressed air is you NEVER HOLD YOUR BREATH.The only thing near what you are talking about is Snuba, where there is compressed air on the surface and you are tethered with a hose. (think commercial diver without all the gear.)

If you hold your breath while breathing compressed air you are asking for trouble. The depths you would be diving would probably be in the 30' depth area, which are the most dangerous as volumes double in that first ~33'. (I think it's 0.45psi per foot, in saltwater) Imagine if you are in 10'swells and you are right under one when you take a deep breath at 10'. While the swell is over you you are now at 20' and don't even know it, as it passes you are immediately back at 10', a huge pressure change quickly. That's why I teach my divers to take medium breaths and not filling their lungs up all the way when doing beach entries and swimming out under waves and swells.

What you want to do would be dangerous, not to mention you would need to be certified to by compressed air...even a pony bottle. Take a scuba class and just go scuba diving, you can stay down for an hour easily at shallower depths and it's very relaxing.

I don't know if decompression is really an issue here. 5 minutes at 65' probably wouldn't even require a safety stop if one were using Navy tables. Lung embolisms are also fairly easy to avoid.

I wouldn't recommend that they try this without proper supervision but it doesn't seem all that dangerous to go fool around with a pony bottle.

No recreational diving requires a stop, that's why they are called "recommended" and "safety stop", but I do them. You cannot predict who will get DCI, you need to know the person and conditions before even attempting to guess. (cold water, is the person well hydrated, etc.)

As for barotrauma, it only takes ~4ft of depth before you can theoretically rupture lung tissue. If the person gets a little air stuck in some part of the lung due to congestion, poor health, or something along those lines, they can injure their lung. Once there is even a small rupture from an aveoli or ten, you will continue leaking air into the pleural cavity...not good.

Diving with compressed air takes training, and I would NOT suggest "playing" with a pony bottle. I'll leave it at that.

 

[dug777]

If you haven't had the relevant certified scuba training, don't screw around with a tank.

Also, there's no wai on earth you could hold your breath for 1.5 mins ten times consecutively on a single exhalation/inhalation each time, or indeed that anyone could do that

 

[JonTom]

Okay, lots of people have mentioned what a bad idea this is, so I will let it go with just saying Don't Do It. Get OWD certified, it isn't too expensive and breathing underwater is amazing.

Originally posted by: 911paramedic
Imagine if you are in 10'swells and you are right under one when you take a deep breath at 10'. While the swell is over you you are now at 20' and don't even know it, as it passes you are immediately back at 10', a huge pressure change quickly.

Is this right?

 

[dug777]

Originally posted by: JonTom
Okay, lots of people have mentioned what a bad idea this is, so I will let it go with just saying Don't Do It. Get OWD certified, it isn't too expensive and breathing underwater is amazing.

Originally posted by: 911paramedic
Imagine if you are in 10'swells and you are right under one when you take a deep breath at 10'. While the swell is over you you are now at 20' and don't even know it, as it passes you are immediately back at 10', a huge pressure change quickly.

Is this right?

Well, speaking from someone who's dived in a heavy swell many a time, i've always survived, but i can't imagine ANYONE would ever dive in 10 foot swell conditions (that's great surfing sea, not diving)

 

[JonTom]

Originally posted by: dug777

Originally posted by: JonTom
Okay, lots of people have mentioned what a bad idea this is, so I will let it go with just saying Don't Do It. Get OWD certified, it isn't too expensive and breathing underwater is amazing.

Originally posted by: 911paramedic
Imagine if you are in 10'swells and you are right under one when you take a deep breath at 10'. While the swell is over you you are now at 20' and don't even know it, as it passes you are immediately back at 10', a huge pressure change quickly.

Is this right?

Well, speaking from someone who's dived in a heavy swell many a time, i've always survived, but i can't imagine ANYONE would ever dive in 10 foot swell conditions (that's great surfing sea, not diving)

Yeah, okay, but the principle, is it sound?????

 

[uberman]

Originally posted by: JonTom

Originally posted by: dug777

Originally posted by: JonTom
Okay, lots of people have mentioned what a bad idea this is, so I will let it go with just saying Don't Do It. Get OWD certified, it isn't too expensive and breathing underwater is amazing.

Originally posted by: 911paramedic
Imagine if you are in 10'swells and you are right under one when you take a deep breath at 10'. While the swell is over you you are now at 20' and don't even know it, as it passes you are immediately back at 10', a huge pressure change quickly.

Is this right?

Well, speaking from someone who's dived in a heavy swell many a time, i've always survived, but i can't imagine ANYONE would ever dive in 10 foot swell conditions (that's great surfing sea, not diving)

Yeah, okay, but the principle, is it sound?????

I've spent several times between dives watching the swells register a change of 12 to 14 feet on sonar from the bottom of the trough to the top of the wave. That's in Mendocino County in California. Sometimes it's like that, you just do it or go home.
I find diving more difficult at Quadra or Denman island on Vancouver Island in British Columbia. I enjoyed huge 4 meter octopus at Denman, measuring as though all legs were extended by diameter.
I've dived prior to slack, but then I'm in a river. Take away the river and give me waves.

 

[AndrewR]

Originally posted by: 911paramedic

Originally posted by: swimscubasteve

Originally posted by: 911paramedic
OK, I am a master scuba instructor. (seriously)

No is your answer, that would not work for many reasons. Hold your breath for 1.5 min? OK, but after doing that you will gasp and take several deep breaths to compensate for the O2 shortage, that's just physiology. BTW, the number one rule of breathing (<--key word) compressed air is you NEVER HOLD YOUR BREATH.The only thing near what you are talking about is Snuba, where there is compressed air on the surface and you are tethered with a hose. (think commercial diver without all the gear.)

If you hold your breath while breathing compressed air you are asking for trouble. The depths you would be diving would probably be in the 30' depth area, which are the most dangerous as volumes double in that first ~33'. (I think it's 0.45psi per foot, in saltwater) Imagine if you are in 10'swells and you are right under one when you take a deep breath at 10'. While the swell is over you you are now at 20' and don't even know it, as it passes you are immediately back at 10', a huge pressure change quickly. That's why I teach my divers to take medium breaths and not filling their lungs up all the way when doing beach entries and swimming out under waves and swells.

What you want to do would be dangerous, not to mention you would need to be certified to by compressed air...even a pony bottle. Take a scuba class and just go scuba diving, you can stay down for an hour easily at shallower depths and it's very relaxing.

I don't know if decompression is really an issue here. 5 minutes at 65' probably wouldn't even require a safety stop if one were using Navy tables. Lung embolisms are also fairly easy to avoid.

I wouldn't recommend that they try this without proper supervision but it doesn't seem all that dangerous to go fool around with a pony bottle.

No recreational diving requires a stop, that's why they are called "recommended" and "safety stop", but I do them. You cannot predict who will get DCI, you need to know the person and conditions before even attempting to guess. (cold water, is the person well hydrated, etc.)

I think that's a dangerous statement, that no recreational diving requires a deco stop. That being said, I would be very surprised that anyone in a situation requiring one would be unaware of the dangers.

Case in point, I remember one dive where we went down to about 130' at the deepest and stayed below 90' for the entire dive. It was the first dive of two for the day, and had we not completed a deco stop, the second dive could have been a problem (we stayed about 70-90 ft on that one).

All right, I need to stay out of this thread because I want to grab my gear and go. Unfortunately, my gear is warm water; I'm in Ohio; and it's pretty damn cold out there.