KerryS Posted January 13, 2011 Posted January 13, 2011 Google Tanya Streeter for free diving stuff Quote
Tubs Posted January 13, 2011 Posted January 13, 2011 "The bends" results from dissolved gasses in the blood returning to their gaseous state as you surface. IIRC, above 20m you do not need to schedule decompression stops, but it's a good idea to breathe out as you surface to relieve pressure inside your lungs, assuming you went down on one breath. If you dive with scuba gear, 20m is still the safe lower limit but obviously you can breathe normally on the way up... I think... How long you've been down at pressure also has a bearing on how much gas may be dissolved in to your blood stream, and how often and for how long you should decompress for on the way up... This only applies if you have been breathing compressed air. If you free dive the pressure in your lungs is 1 atm. Yes, this will rise as you go down and your body and especially your lungs are compressed but not significantly when compared to a scuba dive. When you free dive there is no requirement to breath out as you ascend. Tubs Quote
cast iron Posted January 13, 2011 Posted January 13, 2011 but it's a good idea to breathe out as you surface to relieve pressure inside your lungs, assuming you went down on one breath not sure how you'd take any more than one breath if yopu're free diving PMSL new keyboard please Quote
Blatman Posted January 14, 2011 Posted January 14, 2011 This only applies if you have been breathing compressed air. The "compressor divers" in the Phillipines (I think) on BBC1's "The Human Planet" last night were not breathing compressed air, and several of them got the bends, surfacing too quickly from around 20 metres having been down there for a few hours. It appeared to me that the compressor (a regular air compressor like you'd use for air tools, only diesel powered) was supplying a stream of air down what was effectively garden hose, so ther is no way the air was compressed in any way. It was fascinating to watch... Quote
Tubs Posted January 14, 2011 Posted January 14, 2011 This only applies if you have been breathing compressed air. The "compressor divers" in the Phillipines (I think) on BBC1's "The Human Planet" last night were not breathing compressed air, and several of them got the bends, surfacing too quickly from around 20 metres having been down there for a few hours. It appeared to me that the compressor (a regular air compressor like you'd use for air tools, only diesel powered) was supplying a stream of air down what was effectively garden hose, so ther is no way the air was compressed in any way. It was fascinating to watch... The air they are breathing is compressed it is just not SCUBA. Lungs are feeble devices and if the air is not compressed to match the pressure being placed on the body, in this case by being under water, then you cannot breath. Next time you are in a swimming pool just try lying on the bottom and breath through a hose to the surface. You will struggle to breath if you are more than a foot under water. We tried this when we did our NAUI Scuba course and it really confused the girls. Tubs Quote
langy Posted January 14, 2011 Posted January 14, 2011 Google Tanya Streeter for free diving stuff Indeed Quote
Tubs Posted January 14, 2011 Posted January 14, 2011 Google Tanya Streeter for free diving stuff Indeed Found this rather interesting article where, in the third paragraph, Tanya completes a world record dive on land. Apparently. Some going, even for Tanya. Tanya Land Diving Tubs Quote
jackdaw Posted January 14, 2011 Posted January 14, 2011 This only applies if you have been breathing compressed air. The "compressor divers" in the Phillipines (I think) on BBC1's "The Human Planet" last night were not breathing compressed air, and several of them got the bends, surfacing too quickly from around 20 metres having been down there for a few hours. It appeared to me that the compressor (a regular air compressor like you'd use for air tools, only diesel powered) was supplying a stream of air down what was effectively garden hose, so ther is no way the air was compressed in any way. It was fascinating to watch... The air they are breathing is compressed it is just not SCUBA. Lungs are feeble devices and if the air is not compressed to match the pressure being placed on the body, in this case by being under water, then you cannot breath. Next time you are in a swimming pool just try lying on the bottom and breath through a hose to the surface. You will struggle to breath if you are more than a foot under water. We tried this when we did our NAUI Scuba course and it really confused the girls. Tubs can't quite remember from my scuba days but i think it's boyles law 20m = 2 attmospheres so any air at that depth will be compressed the deeper you go the greater the compression. Fill your lungs and rise to the surface holding your breath, the air becomes less compressed expands and bursts your lungs. A bend is caused by a build up of nitrogen forming bubbles in the blood stream due to changing pressure quickly before the body has had time to get rid of the nitrogen. similar to opening a bottle of pop. Free divers along with submariners breath air at one atmosphere and will not suffer a bend however deep they go. Quote
Blatman Posted January 15, 2011 Posted January 15, 2011 I understand the principles. Here's a clip of what I'm on about... Quote
Tubs Posted January 15, 2011 Posted January 15, 2011 The divers in this clip can get the bends because they are breathing compressed air. If you are free diving there is no compressed air so you can't get the bends. Tubs. Quote
jackdaw Posted January 15, 2011 Posted January 15, 2011 The divers in this clip can get the bends because they are breathing compressed air. If you are free diving there is no compressed air so you can't get the bends. Tubs. what tubs says is correct, but the air is'nt compressed because of the way its supplied, it's compressed by the depth of water, at 20m two atmos at 40m 4 atmos etc. Scuba equipment supplies air at the ambient pressure via a regulater close to the surface you are breathing at a lower pressure than at depth this is why a tank full of air lasts much longer on a 10 metre dive than on a 40m dive. Quote
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