SAC rate

[boles_ed@hotmail.com]

Robert,

I know this sounds simplistic but your best solution to this very very simple. Just dive. The more you dive the better it will get plain and simple. I too once struggled with my mind on how fast I emptied a tank. In the end when its all said and done you will breath at your own rate. When I started diving I was trying to metric myself against 200+ dive divers. I got discouraged, talked to people, then got discouraged again and went round and round. Then I just decided what I breathed is what I breathed and bam one day I was going 40 plus minutes in Cozumel on pretty deep dives. If someone is giving you grief about your air management find somebody else to dive with!!! You should never get into an air war. Its just something that takes a little time say 50 good dives. Thankfully the ride is just as cool as the destination!! Just relax, tuck in your arms, and enjoy the calm quiet of the water.

 

[rab1412000]

well almost everyone covered the topic well, ill just add a few more tidbits.

first of all dont sweat your air consumption. all tall, big guys suck a lot of air, and being a beginner, im guessing theres still a wee bit of anxiety and stress when entering the water - which is normal. consciously trying to calm yourself down before the dive helps a lot. better yet, try to dive with a more experienced buddy who can give you a few words of confidence and reassurance. also try not to think about your sac rate(again additional stress) and just enjoy the dive.
over time, you will improve , but just like i mentioned dont expect to have the air capacity of a teenage girl.
just like previously mentioned, keeping yourself streamlined and as horizontal as possible is also key. i would like to add though that getting a good pair of fins also goes a long way. i dive with old tusa liberator x fins that are heavy and almost impossible to snorkel with. i would not reccomend them to a beginner. get something like the scubapro jetfins and do a frog kick instead of a flutter.


my 2 psi

 

[Puffer Fish]

What would an average SAC for a dive at say 50'? Just wondering I playing with my new dive computer and wondering what and average number for SAC would be. I know it can vary a lot depending on the person but what is an average?

Average male... average female... average small person.. average large?

Most experienced, comfortable male divers (assuming they are not really big) will be around .5...most females will be around .4. New divers, add .2 to the number..or more.

But there is a lot of variation between the size and air demands..have seen females around .3, for example.

 

[SCUBA482]

Average male... average female... average small person.. average large?

Most experienced, comfortable male divers (assuming they are not really big) will be around .5...most females will be around .4. New divers, add .2 to the number..or more.

But there is a lot of variation between the size and air demands..have seen females around .3, for example.

Glad this got answered...I was going to ask a very similar question....now to calculate my SAC

 

[SCUBA482]

First here is a link to calculate your SAC rate.
SAC Calculator

Second, don't fret it. Keep diving and learn to relax and your SAC will slowly improve.

Teamcasa,

Thanks for the link, was nice to use and see that what you said in your post couldn't be more true...i only have 13 dives and on each one my sac has gotten lower. Still higher than I'd like, but it will get better I'm sure. I went from a high sac of 1.160 to the lowest of .714. I'm 6'2" and weight 235 lbs. I might add that while looking at my log I see that each dive has gotten better and I was more comfortable and my buoyancy felt better (even dropped 6 lbs from my weights). Anyway, all this to say to the OP that don't fret...I can see that what has been posted is true on my dives...things do get better with more BT

 

[it_mike]

<HIJACK>

We need a SAC thead!

I've always wondered how my consumption compared to other divers, and now a have an inkling. For example, I did a working dive last week, with physical exertion, and my SAC was .73. My buddy, who was spotting and doing light work, was .37. Without a calculator handy, just looking at PSI utilization, I was shocked at the difference. But in thinking about it, I was the one manhandling the tube, methodically sifting through the bottom, and dragging hoses around. I'll have to pay attention to my next 'relaxing' dive and see what my 'real' SAC is.

<END HIJACK>

BTW, we're both seasoned divers doing routine volunteer work.

 

[GrandpaScuba]

As a newbie I'm just figuring out things. While on a trip to Florida this month discovered my sac rate was only 28.

28 what? Are you saying 28 psi/min.? You should convert your SAC to cuft/min. Using psi/min, your SAC is only valid for the exact same kind of tank you were using at the time. If you convert to cuft/min, you can use it with any kind of tank.

If you want to know about "gas management," which is what your question is really about, send a message to NWGRATEFULDIVER, he is one of the foremost experts on gas management.

 

[TSandM]

No need to PM Bob -- He put his article up on his website. There's a lot of other good stuff there, too.

One thing everybody should keep in mind is that SAC rate is a variable, not a constant. Anything that adds to workload or stress can change it. My SAC rate when I first started running line in caves almost doubled, but has come down as I've gotten better at it. Swimming hard into Ginnie Springs a week ago, my gas consumption came close to triple what it is at home on a non-working dive.

 

[pengwe]

The 28 sounds like litres per minute, which would be equivalent to just under 1 cuft/minute.

edit: oh, RA is from Nth Carolina, so probably not using litres, nvm.

 

[Kevrumbo]

Maybe he did mean 28 litres/min --otherwise the OP doesn't make much sense to me.

My nominal cold water SAC is 21 litres/min (same as .75 cf/min), and my warm water is 15 litres/min (.55 cf/min).