Newbie SAC

[NAVMED82]

My wife and I did our check-out dives in Lake Jocassie in April with nice cold 50 degree water. We were just going back through our stuff calculating our SACs, and I had a question. I noticed that I used alot less air than her, and no big shock my SAC is half her's. Mine is .5 ft^3/min, her's was 1 ft^3/min. Who's normal? Am I really low, or is she high?

Matt

 

[jbd]

Yours is pretty good. Hers is high although not what I would consider abnormal for just starting out. Typically though a female will have a lower SAC rate than a male will.

What are some thins that may account for the differences between the two of you. At this point primarily stress IMO along with possible physical condition. You may be in better condition than she is if you are running, biking etc and she is not. She may not be as relaxed and comfortable in the water as you are.

If she likes diving and continues to dive frequently I would expect her to lower her SAC rate to something in the 0.4 to 0.5 range.

Most important though is not the actual numbers themselves but that you recognize there is the difference and plan your dive based on her SAC rate and not yours.

BTW I'm curious as to why it was, "no big shock that my SAC is half hers".

 

[Matteo]

for both of you being new divers, yours seems pretty darn good and hers seems just a tad bit high, but this is hard to gauge without having a little more data for the sample...give yourselves a few more dives and you will have a better idea of your averages

 

[SparticleBrane]

Both are equally acceptable for brand new divers. I would suggest, though, that she seems to be somewhat tense in the water if she's sucking down that much air. Over time as she becomes more relaxed, her air consumption will probably drop.
Highest I've ever had was 0.84, and that was on my first dive with doubles. After that first time I was slightly more relaxed and it dropped to 0.5.

Just to be sure, how are you calculating your SAC? Are you using the average depth given to you by a dive computer/bottom timer?
edit: I am asking specifically because I've seen some people use some interesting numbers. Like--they'll just pull a number out of the air as their average depth, or they'll use their deepest depth--things like that.

 

[spectrum]

Together you are about average.

As long as you are diving at a leisurely pase I find comfort in the water to be the big driver over physical condition.

Diving need not (should not) be hard work but it is something that some folks need time to get relaxed with.

Now get out there and collect some new data.

Pete

 

[NAVMED82]

It was average depth from a computer. It wasn't a shock that the actually number was half, becasue I was ending up with about twice as much air at the end as her for the same dive. Thanks for the info. I was a firefighter for a while before this, so I'm very comfortable breathing from a bottle in a stressfull situation. Thanks for the info.

 

[pengwe]

Another thing is that she may have been more affected by the cold than you. That would make her air consumption higher.