drrich2
Contributor
In that case, petite women with low air consumption are in serious danger from diving with 80 cf tanks & shouldn't be allowed to use them.
Richard.
How to reduce a monstrous SAC
- Thread starter GramsciBeat
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In that case, petite women with low air consumption are in serious danger from diving with 80 cf tanks & shouldn't be allowed to use them.
Richard.
OP
GramsciBeat
Contributor
This weekend was my first opportunity to put in to practice some of the suggestions that were made in response to my query. I must say I the outcomes seriously exceeded my expectations. My SAC ranged between 15.4 to 17.2 litre per minute for the 5 dives I did over the weekend with an overall average of about 16l (0.56 cu foot, I think). All-in-all, a serious improvement.
I reckon these were some of the most helpful things I did:
I already have an AI computer, so before going diving this weekend, I analysed my breathing on previous dives looking at where my consumption was at its highest and what the common factors were. I wasnt surprised that it was highest at the beginning of all the dives, but it was much worse than I expected. On this basis, I decided to adjust my attitude away from needing to be the quickest swimmer on the surface and the first one down to the bottom. I just really took it easy swimming out to the start point, had a rest before descending, and instead of finning down as quickly as possible, I allowed gravity do its work.
Once down I really focused on doing as little as possible if one kick would work to get from A to B that would be all I would do. Part of this was also relaxing and as counter-intuitive as concentrating on being relaxed felt at first, it definitely worked. By just being, I felt where small currents were going and I was able to let them do the work for me.
As well as concentrating on relaxing, I also concentrated on breathing ensuring that it was diaphragmatic and that I slowed it down to about four breaths a minute, a rate that was based on what was comfortable for me and it seems to have worked.
I also asked one of the guys I dive with regularly (and who is very experienced) whether he had any suggestions regarding my style and trim under water. With the exception of recommending that I slow down, he said it was pretty much sorted though obviously there is always room for fine-tuning.
There are other suggestions that were made (such as the yoga) which I look forward to doing. But I am very impressed; its not often that Internet advice actually works let alone as well as this.
I reckon these were some of the most helpful things I did:
I already have an AI computer, so before going diving this weekend, I analysed my breathing on previous dives looking at where my consumption was at its highest and what the common factors were. I wasnt surprised that it was highest at the beginning of all the dives, but it was much worse than I expected. On this basis, I decided to adjust my attitude away from needing to be the quickest swimmer on the surface and the first one down to the bottom. I just really took it easy swimming out to the start point, had a rest before descending, and instead of finning down as quickly as possible, I allowed gravity do its work.
Once down I really focused on doing as little as possible if one kick would work to get from A to B that would be all I would do. Part of this was also relaxing and as counter-intuitive as concentrating on being relaxed felt at first, it definitely worked. By just being, I felt where small currents were going and I was able to let them do the work for me.
As well as concentrating on relaxing, I also concentrated on breathing ensuring that it was diaphragmatic and that I slowed it down to about four breaths a minute, a rate that was based on what was comfortable for me and it seems to have worked.
I also asked one of the guys I dive with regularly (and who is very experienced) whether he had any suggestions regarding my style and trim under water. With the exception of recommending that I slow down, he said it was pretty much sorted though obviously there is always room for fine-tuning.
There are other suggestions that were made (such as the yoga) which I look forward to doing. But I am very impressed; its not often that Internet advice actually works let alone as well as this.
Last edited:
OP
GramsciBeat
Contributor
& now my 2 cents on metric v outdated and arcane measuring systems.
I have lived in both metric and non-metric countries. Transitioning between the two in terms of being able to picture whether a weight is heavy or a distance far is not too much of a mission, especially for the more commonly used units such as height, distance and weight (although I never could get my head around 'stones'). The main difference is that metric is just so much easier.
Somebody posted that with computers there is no need to transition to metric, well with metric there is no need to use computers. If a distance grows so it's no longer practical to use meters - just add a couple of zeroes and you're using kilometres. Whether it is volume, distance whatever, all measurements are completely scaleable. How easy is that compared to working in feet, yards and miles?
Also metric is integrated - at 0m above sea-level water boils at 100 degrees celisius and freezes at zero. Likewise 1000km/h at sea level is the speed of sound. Simple.
PADI course material is the best illustration of the efficiency of the two systems - when illustrating how to complete calculations the book uses metric and imperial. The metric example is less than a paragraph, the imperial a minimum of page. When you get to the D-Tec stuff the difference is even greater.
So, in short, I'll take mine metric then.
I have lived in both metric and non-metric countries. Transitioning between the two in terms of being able to picture whether a weight is heavy or a distance far is not too much of a mission, especially for the more commonly used units such as height, distance and weight (although I never could get my head around 'stones'). The main difference is that metric is just so much easier.
Somebody posted that with computers there is no need to transition to metric, well with metric there is no need to use computers. If a distance grows so it's no longer practical to use meters - just add a couple of zeroes and you're using kilometres. Whether it is volume, distance whatever, all measurements are completely scaleable. How easy is that compared to working in feet, yards and miles?
Also metric is integrated - at 0m above sea-level water boils at 100 degrees celisius and freezes at zero. Likewise 1000km/h at sea level is the speed of sound. Simple.
PADI course material is the best illustration of the efficiency of the two systems - when illustrating how to complete calculations the book uses metric and imperial. The metric example is less than a paragraph, the imperial a minimum of page. When you get to the D-Tec stuff the difference is even greater.
So, in short, I'll take mine metric then.
It's very, very good to read about your success! Kudos to you! I've found in working with divers who have high air consumption rates that a combination of many seemingly small changes typically produces significant improvement. It seems likely to me that most of these small changes impact one another and have a greater cumulative effect than any one or two together would produce. Thus, efficient finning means less work and therefore fewer breaths per minute; diving at a more relaxed pace means not having to fin constantly so that it's possible to kick and glide; and so on.
Among my divers, the most impressive success story was a body-builder who aspired to be a dive pro. His diving was pretty good, but he would go through a 15 l tank (in imperial I guess it's a 100 cu ft) in half an hour, so I told him that our primary goal in working on his dive skills would be for the customers to go low on air before he did. We worked on efficient technique, breath control, zen.... and he did it! By the time he finished his DM course, he was doing a 60 minute dive on a 12 l tank (80 cu ft). I believe his success was due to a combination of small changes that added up--no multiplied--to produce big results.
Again, well done to you!
Among my divers, the most impressive success story was a body-builder who aspired to be a dive pro. His diving was pretty good, but he would go through a 15 l tank (in imperial I guess it's a 100 cu ft) in half an hour, so I told him that our primary goal in working on his dive skills would be for the customers to go low on air before he did. We worked on efficient technique, breath control, zen.... and he did it! By the time he finished his DM course, he was doing a 60 minute dive on a 12 l tank (80 cu ft). I believe his success was due to a combination of small changes that added up--no multiplied--to produce big results.
Again, well done to you!
Excellent! A .5 cuft. rate is probably approaching your " normal rate ".
Make sure to keep downloading your dives and analyzing your heart rate and breathing rate after every dive.
Good Luck & Good Diving!
Make sure to keep downloading your dives and analyzing your heart rate and breathing rate after every dive.
Good Luck & Good Diving!
Kevrumbo
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15 litres/min divided-by 15 litres/bar tank is 1 bar/min pressure SCR per 1ATA --good for you!
So for example, if you're at 30 meters average or max depth for 10 minutes with nominal exertion:
30m is 4 ATA (30 meters divided-by-10 plus 1 equals 4 ATA);
4 ATA mulitplied-by 1 bar/min, and then multiplied by 10 minutes equals 40 bar consumed in that time frame of 10 minutes at 30 meters.
You really don't need your Air Integrated Computer to tell you this anymore --just simply a standard "brass & glass" SPG in bar units and rote common sense
. . .
So for example, if you're at 30 meters average or max depth for 10 minutes with nominal exertion:
30m is 4 ATA (30 meters divided-by-10 plus 1 equals 4 ATA);
4 ATA mulitplied-by 1 bar/min, and then multiplied by 10 minutes equals 40 bar consumed in that time frame of 10 minutes at 30 meters.
You really don't need your Air Integrated Computer to tell you this anymore --just simply a standard "brass & glass" SPG in bar units and rote common sense
. . .
So how does this simple math compare with being able to analyze your dive from a sample that the Galileo Sol takes every 4 seconds?You really don't need your Air Integrated Computer to tell you this anymore --just simply a standard "brass & glass" SPG in bar units and rote common sense
gcarter
Contributor
I always wear two computers!
gcarter
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