Tech training with a high SAC

[aquaregia]

I've seen in other threads references such as "if your SAC is that high you shouldn't be doing technical diving." I'm considering taking some more advanced classes, but I'm pretty sure that statement applies to me.

My normal diving SAC is around 0.8cf/min and my shtf SAC is around 1.2cf/min, and those numbers haven't changed in the last hundred dives. I'm psychologically comfortable underwater, swim okay, and can run a half marathon without too much trouble. I have a tendency to be somewhat stiff (both in and out of the water), as many sports coaches have pointed out, and I do tend to idly fin for no particular reason, so I think these might be the cause. Alternatively, I could just be a bigger guy. Alternatively, half marathons might not be the best indicator of my cardiovascular health.

Thoughts?

 

[redacted]

You might find your "easy chair" SAC to be a useful baseline. Favorite recliner, tank with regulator and a mask to seal your nose. Stay awake but really relax. With a good SPG, you should be able to get a fairly accurate measure in 15 to 30 minutes. (Warning: People will laugh) Then you can work on accounting for the differences. Plus, remember that relaxed feeling in the chair and maybe try to do something similar on a dive. A neutrally buoyant suspension is about as comfortable as that easy chair if temps are good.

As I recall, mine was about .25 while my in-water SAC for warm, low effort dives runs .4 to .5. I suspect I may even be able to get close to .3 with the tips of my fins in the sand as I spend 10 to 15 minutes watching something like a Jaw Fish with eggs do her thing. It has that easy chair feeling.

 

[TSandM]

My long-term favorite dive buddy has a SAC rate of about .7. He's doing trimix with AG this summer . . . You just might have to adjust some of your rock bottom values for your gas consumption, is all.

I think the "you should tech dive if you breathe like that" comment is more aimed at people whose SAC rate is high because of lack of comfort or poor technique/efficiency. What you breathe is what you breathe.

 

[knowone]

Dude, you sound like a tall dude, dude.

I don't remember what my rate was when I did all that stuff, or how much
progressive deterioration has ocurred, but laying line and pushing 150 kilos
with no mask or reg never lay within my comfort zone especially after a good
punch in the guts.

If you wanted to do some training and shrink yourself down to
about 5'6 then you could become the perfect diver dude, dude.

 

[lowviz]

You might find your "easy chair" SAC to be a useful baseline. Favorite recliner, tank with regulator and a mask to seal your nose. .............//...........As I recall, mine was about .25 while my in-water SAC for warm, low effort dives runs .4 to .5. ...............//..........

Same here, "easy chair" SAC is very close to yours. However, I use 0.75 for gas planning in cold salt water because that is what it is going to be. (every time!)

I used to sweat my SAC until I learned (from cavers) how to sidemount 80's while diving manifolded double HP100's. Run a reel. Drop the teh 80's at their first thirds and retrieve them on the return trip. You will need a tailplate (buttplate) and a 17" bungee. Won't even know you added either to your tech rig. Minor modifications, massive impact.

Focus on the things that will hurt you, just take your SAC for what it is.

Stay safe,
lowviz

 

[farsidefan1]

Size is a major determining factor although I dove with Bas Noij in Bonaire (about 6'7" and very well built) and he was even more efficient than my wife (she is 5'3" 125 and is currently training for an iron man competition. I'm 5'11" 235 and 60 yrs old. My warm water sac (I just chedked my last 40 dives) was between .44 and .54 but I coast after every kick, stay extremely linear and usually frog kick. I try to be very "still" when not moving. Your athleticism, cardio and experience should allow you to be much more efficient. 2 thoughts, first, of course you know that a low sac does not necessarily = a good diver although those with a low sac try to make you feel this way (nuts to them) and second, it sounds to me as if yours is a problem of focus. Concentrate on being still and stopping the unnecessary kicking. given the other factors I think it is just a matter of focusing on these small changes.

 

[lowviz]

..//...I don't remember what my rate was when I did all that stuff, or how much
progressive deterioration has ocurred, but laying line and pushing 150 kilos
with no mask or reg never lay within my comfort zone especially after a good
punch in the guts....//.......

-not buying paws in the air from you of all people. Knock it off.

@AquaRegia: my generation is noted for not going down without a good fight. Scr*w the SAC, just deal with it.

 

[MXGratefulDiver]

I say don't worry about it. Pursue your interests. If consumption rate becomes the limiting factor, get bigger tanks ...

... Bob (Grateful Diver)

 

[ianr33]

If consumption rate becomes the limiting factor, get bigger tanks ...

... Bob (Grateful Diver)

I prefer having the same size tanks as my buddy. All that gas matching stuff makes my head hurt.

 

[MXGratefulDiver]

I prefer having the same size tanks as my buddy. All that gas matching stuff makes my head hurt.

It's not that hard, really. For two given divers, reserves are the same at any given depth regardless of cylinder size. If you know your reserves in CF, it's simple enough to convert it to PSI for varying size cylinders.

For example, if I'm using 119's and you're using 130's and we need to keep 140 CF in reserve for both divers, your rock bottom is 1900 ... mine's a bit less than 2100, so let's just say 2100.

So whichever one of us reaches that number first turns the dive.

No big whoop ... that's simple enough to do in your head.

... Bob (Grateful Diver)