Real time SAC? How? (Ridiculous SAC)

[estresao]

HI everyone,

After few dives, around 20, I've took some GUE training and changed my "diving style" causing a ridiculous SAC increment which, some times.... many times.... is coul be more than 30 liters/minutes. Today I have 97 dives under my belt, of which around 70 were done using the new configuratrion, so I think I had time enought to improve anything I'm doing wrong and cannot tell what is.Before the change, still very novice, my SAC was 14-15 liters/minute... some times 12-13, so was not bad for a newbie, and demonstrate my lungs are not rotten LOL.

I don't feel nervous nor tired so don't think my SAC is because of that (who knows). I think is more bad breathing technique.... I think, but not yet sure.

I think it could be because the way I'm controlling the buoyancy, but not pretty sure yet. My hypothesis is I'm too afraid to go up too quick and trend to be under buoyant controlling the buoyancy "by lungs", i mean, rather to breath in a middle lung range I use also the high range to get proper buoyant. I thknk that's happening becaise when under load (basic 5, valves or whatever) I sink rather to keep at the same deep.That's is my current theory, but not yet confirmed.

Also can fell sometimes I don't feel confortable with my gear preventing me from stay still when, for example, performing a basic 5, when I trend to move ahead lite by litle. Also feel some times low back disconfort, which makes me thknk I'm "overworking" for my position.

Regarding that I was thinking whether it's possible to monitor the SAC real time when diving so that I can realize when I'm doing whatever I do wrong and find out what's going on. For example, my current computer is a very basic one and was thinking in get a Perdix, which I wonder whether the AI version with a transmiter provides you with the real time SAC durig a dive?

Any other recommendation would be welcome.

 

[rongoodman]

What does your GUE instructor have to say about it?

 

[Heat Miser]

Sometimes you can be so focused on holding a safety stop at 3-5m that you end up slightly overweighted.

The extra weight has to be carried around during the dive and causes higher SAC rates, I'd be surprised if an extra weight would be that big a difference though, Id like to hear what you GUE instructor sai?

Obviously twins have lower sac rate than singles because sac is measured in bar (/ pressure)

 

[Graeme Fraser]

+1 for speaking to your instructor.

In the meantime, three things:

I - how are you currently calculating your SAC?
2 - have you changed your cylinder? (i.e capacity)
3 - are you practicing drills on every dive?

 

[estresao]

What does your GUE instructor have to say about it?

In short.... s/he gave not much importance to this particular topic but to others whch could be related in my oppinion. For example, be able to keep in a deep level doinf nothig but don't be able when doing things (first reaction is go deeper). During the training no particular cause were discovered, so I'm still trying to find out.

Sometimes you can be so focused on holding a safety stop at 3-5m that you end up slightly overweighted.

The extra weight has to be carried around during the dive and causes higher SAC rates, I'd be surprised if an extra weight would be that big a difference though, Id like to hear what you GUE instructor sai?

Obviously twins have lower sac rate than singles because sac is measured in bar (/ pressure)

I have worked to fine tume my weight for both, single a doubles, and have absolutelly no problems diving at 2 or almost 1 meter when cilinder are pretty much empty. Actually I do mostly shore diving and always keep my self practicing at this deep, deploying the SMD, etc... Some times I have to dive among others divers legs..... and some times my dive finish up when I touch the sand with my chest and my fins are out the water.

When calculate SAC I always bear in mind the cilinder capacity, starting capacity and final capacity. I makes the calculus but many times, because I use subsurface to log my dives, just get the SAC from it.

+1 for speaking to your instructor.

In the meantime, three things:

I - how are you currently calculating your SAC?
2 - have you changed your cylinder? (i.e capacity)
3 - are you practicing drills on every dive?

I've mentioned this to my instructor, but so far no idea. I've arranged a particular training session with another GUE instructor to put focus on this particular topic.

1.- Most of the time I use Subsurface and some times manual calculus.
2.- I'm always bear in mind the cilynders I use to calculate it. Also when logging the dive into Subsurface.
3.- Not always, but lately I try to practice a when I can.

Extra bonus: For example, yesterday, I dove with my partner, she did using single 12L cilynder starting with 200 bars, myself with doubles (12Lx2) starting 200 bars. Both made exáctly te same dive, same time, same everything. results:
- She end up with 90 bars, which is really goot because it was a SAC of 9-10 liters/minute.
- I finish up with 70 bars, which is not bad bearing in mind my historial, but still 21,7 liters/minute

See following yesterday's dive profile (don't pay much attention to my Giotto warning, please)

 

[loosenit2]

In answer to the OPs question at the end of the post yes the perdix and Teric can show you real time SAC when you use them as AI. I have used the SAC display to help me improve air consumption.

 

[atdotde]

I know my SAC rate heavily depends on how relaxed I am in the water. With any kind of task load or worries it can easily go up significantly. Looking at SAC rates from a number of divers, everybody's minimal SAC rate (totally relaxed dive and diver, at least for experienced divers) is to good approximation proportional to your body mass as it is mostly determined by your basic metabolism. So, if you are a somewhat big bloke you will never achieve the SAC rate of your tiny female buddy.

If you use a dive computer with pressure sensor, Subsurface will also color your cylinder pressure line according to your momentary SAC (but that is somewhat hard to determine, given that there are only a few samples per minute and that cylinder pressure sensors are somewhat crude). But often enough, you can see that the line turns red the moment your task load went up.

 

[aviator8]

In short.... s/he gave not much importance to this particular topic but to others whch could be related in my oppinion. For example, be able to keep in a deep level doinf nothig but don't be able when doing things (first reaction is go deeper). During the training no particular cause were discovered, so I'm still trying to find out.





I have worked to fine tume my weight for both, single a doubles, and have absolutelly no problems diving at 2 or almost 1 meter when cilinder are pretty much empty. Actually I do mostly shore diving and always keep my self practicing at this deep, deploying the SMD, etc... Some times I have to dive among others divers legs..... and some times my dive finish up when I touch the sand with my chest and my fins are out the water.

When calculate SAC I always bear in mind the cilinder capacity, starting capacity and final capacity. I makes the calculus but many times, because I use subsurface to log my dives, just get the SAC from it.





I've mentioned this to my instructor, but so far no idea. I've arranged a particular training session with another GUE instructor to put focus on this particular topic.

1.- Most of the time I use Subsurface and some times manual calculus.
2.- I'm always bear in mind the cilynders I use to calculate it. Also when logging the dive into Subsurface.
3.- Not always, but lately I try to practice a when I can.

Extra bonus: For example, yesterday, I dove with my partner, she did using single 12L cilynder starting with 200 bars, myself with doubles (12Lx2) starting 200 bars. Both made exáctly te same dive, same time, same everything. results:
- She end up with 90 bars, which is really goot because it was a SAC of 9-10 liters/minute.
- I finish up with 70 bars, which is not bad bearing in mind my historial, but still 21,7 liters/minute

See following yesterday's dive profile (don't pay much attention to my Giotto warning, please)
View attachment 539311

What is your height and weight?

 

[drk5036]

In answer to the OPs question at the end of the post yes the perdix and Teric can show you real time SAC when you use them as AI. I have used the SAC display to help me improve air consumption.

What did you input your cylinder size as? How many liters?

 

[loosenit2]

What did you input your cylinder size as? How many liters?

You do not input your cylinder size, it just reports use in psi/min. You would have to use your tank size after the fact to convert psi/min for your tank to ft3 or li3/min.