SAC Rate

[Charlie99]

Here is the oddity of the whole thing. We are told to breath deeply and slowly. We are told not to hold our breath. Doesn't that limit how far one can stretch the SAC?

BTW: In a test on dry land, my yoga teacher did a 0.23 per minute over a 10 minute test... without trying particularly hard.

I breathe deeply, and veerrrrrrryyyy slooooooooooowly.

A nice quiet calm solo dive is very much like yoga for me.

 

[DA Aquamaster]

Personally, If you use a SAC rate for planning, you need to determine it while swimming constantly at fast "cruising speed". I like to swim for a couple minutes as well before starting the timing/checking SPG readings to make sure my breathing rate is stabilized relative to the exertion level.

It gives a higher number but it is much more useful for planning real world scenarios.

Doing this in cold water with doubles and a deco bottle, My SAC runs around .61 to .65 and I usually have more gas left than my buddies at the end of a dive so I suspect I am on the low side of average.

 

[The Kraken]

Lead Bottom,

DA is right . . . use your SAC for planning.
The MRV (minute respiratory volume ???) ie psi/min is a more active indicator of your consumption during the dive.

Your MRV will vary with depth.

the K

 

[Obsessed?]

I practice yoga breathing techniques taught to me by a yogini friend of mine many years ago, and I can keep it just about to .35 - .375 in very ordinary circumstances. Add any additional stress or exertion and it goes up from there. Slow, deep breathing always works best. Over time with experience, your air consumption will become more efficient. It certainly does not hurt to be in good physical shape, focusing on cardio workouts that increase lung efficiency.

 

[eponym]

Here is the oddity of the whole thing. We are told to breath deeply and slowly. We are told not to hold our breath. Doesn't that limit how far one can stretch the SAC?

Not if one also stretches the truth. Another instructor complained recently about an advanced deco student who dramatically understated his consumption when planning dives.

In a test on dry land, my yoga teacher did a 0.23 per minute over a 10 minute test . . . without trying particularly hard.

Wow! And that's why my OW instructor (who had over 5000 dives) had taken up yoga.

Bryan

 

[Fish_Whisperer]

I breathe deeply, and veerrrrrrryyyy slooooooooooowly.

A nice quiet calm solo dive is very much like yoga for me.

Someone, (I think it was Al Maikovsky) told me to breathe as if I were lying on my couch watching TV. I also quit using my hands and got my weight to the right point. Now, when I dive, I fold all of my gauges and crap in towards my cumberbund, and then clasp my left wrist in my right hand, breathe as long and slow as possible, and fin as little as possible. I finally got it into my head that I'm not out there to boogie around the reef. I'm there to just cruise along and absorb what's going on around me. Since then, my dives have been like meditation or something... Very very peaceful, so relaxing, and so much more fun. My SAC has improved dramatically.

 

[NadMat]

Someone, (I think it was Al Maikovsky) told me to breathe as if I were lying on my couch watching TV. I also quit using my hands and got my weight to the right point. Now, when I dive, I fold all of my gauges and crap in towards my cumberbund, and then clasp my left wrist in my right hand, breathe as long and slow as possible, and fin as little as possible. I finally got it into my head that I'm not out there to boogie around the reef. I'm there to just cruise along and absorb what's going on around me. Since then, my dives have been like meditation or something... Very very peaceful, so relaxing, and so much more fun. My SAC has improved dramatically.

Cool, so now I can call it 'skills practice' instead of just being lazy

 

[lead bottom]

I was on a dive in the Keys last week, and a diver on an 80' dive with a single aluminum 80 (air, not nitrox) was underwater for 120 minutes. He said that he deco'd on the way up. He must have because he definitly exceeded his NDL.

Everyone on the boat figured he was dead. Ended up on the surface with 650 psi in his tank. I wouldn't have believed it if I hadn't seen it.

 

[Fish_Whisperer]

Cool, so now I can call it 'skills practice' instead of just being lazy

LOL! Yep! One thing that's often overlooked, especially by new divers like me, (LOL), is the importance of proper weighting. Often, new divers will start out with too much weight because they haven't mastered descending, but if you're at depth and having to constantly playing "bump & dump" with your inflator, then you may need to take a look at perhaps shaving some weight.

At depth, I can cruise along, perfectly neutral, and use my breathing to fine-tune my buoyancy. Inhale and arch my chest upward to rise, or exhale and bend forward a little at the waist to descend.

It's frustrating, as a new diver, to be told, "To improve your SAC, dive! Dive! Dive!" But it is true. The more you dive, the calmer you are, the more accustomed you become to moving slow and easy underwater, getting the most economy out of every movement, and fine-tuning things by streamlining your gear and your trim as much as possible.

 

[Fish_Whisperer]

I was on a dive in the Keys last week, and a diver on an 80' dive with a single aluminum 80 (air, not nitrox) was underwater for 120 minutes. He said that he deco'd on the way up. He must have because he definitly exceeded his NDL.

Everyone on the boat figured he was dead. Ended up on the surface with 650 psi in his tank. I wouldn't have believed it if I hadn't seen it.

Wow! I dove an AL80 on the Spiegel-Grove, and made a 40-minute dive, deco stops included, and got back on the boat with 600 psi left in the tank. A couple of months ago, I would have only been able to make a 20-minute dive on a steel 100. LOL