Something INTERESTING for Scuba &Skydivers

[skybytch 273]

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Anyway, get the board out of your ass, SkyGod.

Perhaps a refresher course in the forum rules is in order here.

In case you're not up to clicking ---
"The rules are:
1) No personal attacks. None."

[JJohnson 0]

I've never seen a shark in the sky, so I'll stick to skydiving. My one overwhelming fear is Shark attack.....so for this kid even the chance of running into a Cadillac with teeth is too much risk.
JJ

JJ

"Call me Darth Balls"

[jraf 0]

Scuba is a different kind of anomal when it comes to relationships between people. I Scuba dive. I know oudles of people who do. Sure the hard core divers have sort of a community and share the commeraderie we have in skydiving. However your average scuba diver will not get excited when he sees another. It has become a popular pastime with people.
Scuba diving - you don't have the feeling of risk. Of course it is there, and if you fuck up you are likely to die. Tha is the difference - you are likely to die. If we fuck up, we just plain die.
I Strongly recommend that you try scuba. It is loads of fun. REMEMBER: After scuba diving NO skydiving for 24 hours!!!. [#0000ff]You dont want your blood to boil, do you [/#bc000c]

jraf

Me Jungleman! Me have large Babalui.
Muff #3275

[skycat 0]

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I've never seen a shark in the sky

Then you have never been to Perris

Fly it like you stole it!

[Stacy 0]

chances are pretty good that when skydiving you won't see many types of fish, won't go through any shipwrecks, and probably will not need your snorkel.

I know I won't do either in the extreme cold. My SCUBA cert dive was in a quarry in PA in March and we had suits so thick we felt like marshmallow people.

[coho21 0]

Oh yeah!! I have and he's floating around here somewhere

J
YSD#0009

[coho21 0]

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My SCUBA cert dive was in a quarry in PA in March and we
had suits so thick we felt like marshmallow people.

I can relate to that. I did my cert dive in the Puget Sound in February. The water was 52 degrees and it was snowing!

J
YSD#0009

[Guest]

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Doesn't that excerpt remind you of skydivers, too?! Do you think it's the nature of high-risk sports that brings about certain behavior characteristics, OR is it the personalities that draws certain people to high-risk sports?

"People who don't climb mountains - the great majority of humankind, that is to say - tend to assume that the sport is a reckless, Dionysian pursuit of ever escalating thrills. But the notion that climbers are merely adrenaline junkies chasing a righteous fix is a fallacy, at least in the case of Everest. What I was doing up there had almost nothing in common with bungee jumping or skydiving or riding a motorcycle at 120 miles per hour.

Above the comforts of Base Camp, the expedition in fact became an almost Calvinistic undertaking. The ratio of misery to pleasure was greater by an order of magnitude than any other mountain I'd been on; I quickly came to understand that climbing Everest was primarily about enduring pain. And in subjecting ourselves to week after week of toil, tedium and suffering, it struck me that most of us were probably seeking, above all else, something like a state of grace."

-- from Into Thin Air, by Jon Krakauer

"The mouse does not know life until it is in the mouth of the cat."

[riddler 0]

I do both. I love both. I like skydiving a little better and do it most weekends, but only go on SCUBA trips once or twice a year.
Both are surreal experiences. Human beings didn't evolve to be able to fall long distances and survive. Neither did they evolve to be able to breathe underwater. For both, the environment is foreign and the experience is mind-blowing. Kinda like brain candy. People who like one will typically like the other. For some reason, though, many SCUBA people think skydivers are crazy.

Trapped on the surface of a sphere. XKCD

[miked10270 0]

Hi There,

Just my $0.02:

Hypoxia is simply put as a shortage of oxygen. By about 15,000' (MSL) there's a reduction of about 40% in available oxygen. This is something that the body CAN handle and experienced skydivers used to going to altitude are probably not even aware of, at least not for the few minutes we're at these altitudes. Go past this - over about 17,000' and you'll almost certainly notice being short of breath - we're heading into supplementary oxygen needs, but it can be done as long as the (unpressurised) plane isn't climbing too fast.

"Climbing too fast" brings us neatly onto our next subject - Nitrogen Narcosis and ultimately the bends. This is a function of reducing pressure too quickly for the body to compensate. The air we breathe is (largely) a mixture of Oxygen & Niotrogen. That goes in and the nitrogen goes out with CO2 (OK that's a gross oversimplification... but). Any excess nitrogen is stored in the tissues - I think it's actually stored in Cancellous Bone (commonly found near to joints).

If you reduce the pressure the body is subject to, then the nitrogen is released from the tissues into the blood for exhalation. If the pressure is reduced too fast then there is an excess of nitrogen in the bloodstream with an effect similar to "Laughing Gas" (Notrous Oxide - geddit?). If the pressure reduction is faster then the nitrogen will form bubbles. It's the bubbles which cause The Bends.

Anyway, the point is that Nitrogen Narcosis and The Bends are caused by rapid pressure reduction whether is's by an air breathing scuba diver surfacing too fast or by a skydiver going up in a plane too high too fast. To avoid this the SCUBA Diver adheres to decompression tables, and strangely enough the skydiver and jump pilot also adhere to similar tables for high altitude jumps.

If you're going high - say 25,000'+, then as a skydiver you'll do 2 things to avoid nitrogen Narcosis and The Bends: 1. You'll "Pre-Breathe" Aviation Oxygen for 20 minutes or more prior to emplaning. This helps your body to purge itself of Nitrogen. 2. The pilot will make his ascent within the limits of your body and doesn't slam the plane up as fast as he can.

This is why commercial high altitude jumps are disproportionately expensive.

Incidentally, for anyone thnking of starting to scuba as well as skydive (and since no-one seems to have mentioned this as yet)... You CAN skydive then scuba. YOU CANNOT SCUBA THEN SKYDIVE!!!!!!! You should leave a clear day at ground level after scuba diving before going up in an unpressurised aircraft. The decompression tables give safe limits for divers returning to the surface air pressure and your body is still saturated with nitrogen after you surface. These tables take no account of you then buggering off into a plane afterwards and it takes your body over 24 hours to purge the excess nitrogen naturally.

Regards,

Mike D10270.

Taking the piss out of the FrenchAmericans since before it was fashionable.

Prenait la pisse hors du FrançaisCanadiens méridionaux puisqu'avant lui à la mode.

[howardwhite 6]

"IMHO these are just reciprocals of each other " (compression and decompression.

Interesting thesis, but how does it deal with the fact that diving involves nitrogen in the bloodstream and flying high doesn't.

In response to other posts, I say again that nitrogen narcosis and the bends are two different animals, both involving nitrogen. I've been "narced" at much too deep, but it goes away quickly on the way up.

HW

[Zenister 0]

thanks mate!
i was wondering that as well..havnt done both in one season yet since this is my first year skydiving..

interestingly i did my altitude tests with the af and they never asked me..the ugly thing is there may have been times when i was pretty close .

great post i'll give you a whole buck for that..

____________________________________
Those who fail to learn from the past are simply Doomed.

[VectorBoy 0]

I do both, I like both, but skydiving kicks ass over it.
They are both social, they are both spacial and require a degree of discipline and training. The dangers in diving stand out in that the gear is very, very heavy, worse so when wet. You may have to traverse rocks and steep climbs to get to good dive spots unless you're boat launching.So you have to be in better than average physical shape.
Many people only dive on vacation when in the warm tropic waters, once a year or less and therefore not very current . And Yes I know cold water sucks. Thats where dives can be deeper and more dangerous. Visability is much better and deaper doesn't seam that far down there when you can easily see a new coin 200 feet away.
As far as shark attacks surfers get it more than divers so don't act like a seal meal. Glen.

[AndyAnderson 0]

Scuba: When everything goes wrong you can go to the surface
Skydiving: When everything goes wrong you will go to the surface.

[Shark 0]

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I've never seen a shark in the sky, so I'll stick to skydiving. My one overwhelming fear is Shark attack.....so for this kid even the chance of running into a Cadillac with teeth is too much risk.
JJ

Yeah, then again, we've never jumped together.

[Airhead 0]

Hiya Kev.
Yeah, Nevada Barr is from Miss. I gather she worked as a Nat'l Park Ranger on the Nachez Trace in Miss. I'm reading all her books right now. All are based in some Nat'l Park- and often include some sort of physical sport, risk and mystery, too.

[Airhead 0]

Very cool excerpt from Into Thin Air. I read that book too a couple of years ago. I hiked the small 'mountain', Mt. Washington, in Massachusetts a couple of times. But it was basically just a long day-hike. But a good climb is really invigerating!
In regards to atmospheric effects, Above Ground Level, at what altitude do physical symptoms start to exhibit themselves? What precautions need to be taken?
Hey, when it comes to atmospheric changes, Below Sea Level: It's what? every twenty feet or so the pressure changeson your brain and blood increasing the nitrogen level in your blood, and there by changing descending-ascending times?? I read somewhere? that for every "atmosphere" in depth, the effect is like one Martini drink on the brain- thus a term: "the martini effect" in scuba diving. Is there a similar effect in high altitude skydiving?

[TheBile 0]

SCUBA rig - Self Contained Underwater Breathing Apparatus
SKYDIVE rig - Self Kontained Yanking Device Invented for Verticle Expression
Just in case you didn't know. (And yes, YANKING is what I meant !)

Gerb

I stir feelings in others they themselves don't understand. KA'CHOW !

[Guest]

Quote

Hi There,

Just my $0.02:

Hypoxia is simply put as a shortage of oxygen. By about 15,000' (MSL) there's a reduction of about 40% in available oxygen. This is something that the body CAN handle and experienced skydivers used to going to altitude are probably not even aware of, at least not for the few minutes we're at these altitudes. Go past this - over about 17,000' and you'll almost certainly notice being short of breath - we're heading into supplementary oxygen needs, but it can be done as long as the (unpressurised) plane isn't climbing too fast.

"Climbing too fast" brings us neatly onto our next subject - Nitrogen Narcosis and ultimately the bends. This is a function of reducing pressure too quickly for the body to compensate. The air we breathe is (largely) a mixture of Oxygen & Niotrogen. That goes in and the nitrogen goes out with CO2 (OK that's a gross oversimplification... but). Any excess nitrogen is stored in the tissues - I think it's actually stored in Cancellous Bone (commonly found near to joints).

If you reduce the pressure the body is subject to, then the nitrogen is released from the tissues into the blood for exhalation. If the pressure is reduced too fast then there is an excess of nitrogen in the bloodstream with an effect similar to "Laughing Gas" (Notrous Oxide - geddit?). If the pressure reduction is faster then the nitrogen will form bubbles. It's the bubbles which cause The Bends.

Anyway, the point is that Nitrogen Narcosis and The Bends are caused by rapid pressure reduction whether is's by an air breathing scuba diver surfacing too fast or by a skydiver going up in a plane too high too fast. To avoid this the SCUBA Diver adheres to decompression tables, and strangely enough the skydiver and jump pilot also adhere to similar tables for high altitude jumps.

If you're going high - say 25,000'+, then as a skydiver you'll do 2 things to avoid nitrogen Narcosis and The Bends: 1. You'll "Pre-Breathe" Aviation Oxygen for 20 minutes or more prior to emplaning. This helps your body to purge itself of Nitrogen. 2. The pilot will make his ascent within the limits of your body and doesn't slam the plane up as fast as he can.

This is why commercial high altitude jumps are disproportionately expensive.

Incidentally, for anyone thnking of starting to scuba as well as skydive (and since no-one seems to have mentioned this as yet)... You CAN skydive then scuba. YOU CANNOT SCUBA THEN SKYDIVE!!!!!!! You should leave a clear day at ground level after scuba diving before going up in an unpressurised aircraft. The decompression tables give safe limits for divers returning to the surface air pressure and your body is still saturated with nitrogen after you surface. These tables take no account of you then buggering off into a plane afterwards and it takes your body over 24 hours to purge the excess nitrogen naturally.

Regards,

Mike D10270.

Gotta chime in here - can't resist -

It was Col John Paul Stapp, MD, USAF, who discovered the "pre-breathing" technique for high-altitude flight. Stapp was Capt Joe Kittinger's boss during the "Man High" projects in the late 50s / early 60s. Please see "The Pre-Astronauts" by Craig Ryan for more details on Stapp, Kittinger, hypoxia, etc.

"The mouse does not know life until it is in the mouth of the cat."