Uhh... not much chance of that...Originally posted by narced_1
if i do it in kg or bar....everyone will think i am european
Air Consumption?
- Thread starter narced_1
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
SAC rates can vary tremendously, depending on what you're doing.
My own resting SAC runs a bit under .4; a typical dive runs between .45 and .50 - I use .5 in planning, unless there's work involved, when I use .75 or above, depending on the job. Just for grins & giggles, I ran my SAC on last summer's encounter with a couple of *serious* bull sharks, when I burned 1600 psi out of a steel 85 in 19 minutes at a max depth of 80', average about 33 for the whole dive... *that* works out to nearly 1.5CFM! And the whole dive I was swimming *real slow*!
Rick
My own resting SAC runs a bit under .4; a typical dive runs between .45 and .50 - I use .5 in planning, unless there's work involved, when I use .75 or above, depending on the job. Just for grins & giggles, I ran my SAC on last summer's encounter with a couple of *serious* bull sharks, when I burned 1600 psi out of a steel 85 in 19 minutes at a max depth of 80', average about 33 for the whole dive... *that* works out to nearly 1.5CFM! And the whole dive I was swimming *real slow*!
Rick
The Chairman
Chairman of the Board
SAC rates can be a lot of "bull" (sorry 'bout the pun). When I first approached SAC rates I did it with an eye on reducing them. I just really wanted to have THE lowest SAC rate on the boat. Sub consciously, I think I even skip breathed a lot, and I seemed to end quite a few dives with headaches and other vague symptoms of malaise. As other have stated, there are a lot of other factors that can temporarily affect your SAC as well.
Well, a year ago I finally "trashed" that concept... and let my breathing govern itself. I have not had a CO2 headache since, and I enjoy the dive a lot more. I even went so far as to buy hp 120s to increase bottom time, so I wouldn't have to try and skimp on breathing to stay down longer. On the other hand, my SAC rate has improved with my conditioning. I work out at least five days a week, with building up my cardiovascular conditioning being the goal. I truly believe that aerobic conditioning of your body is the only SANE way to lower your SAC. Even then, we have to realize that the SAC is not some esoteric goal, but a tool to be able to calculate how deep for how long. My Cobra does a great job of calculating this for every dive, so I don't have to do the math. I do look at it, just to make sure that I am consistent.
BTW, hats off to Roaky for a stunningly good job on the description of the calculations... I hope you don't mind if I put that in my scrap book to use when others ask.
Well, a year ago I finally "trashed" that concept... and let my breathing govern itself. I have not had a CO2 headache since, and I enjoy the dive a lot more. I even went so far as to buy hp 120s to increase bottom time, so I wouldn't have to try and skimp on breathing to stay down longer. On the other hand, my SAC rate has improved with my conditioning. I work out at least five days a week, with building up my cardiovascular conditioning being the goal. I truly believe that aerobic conditioning of your body is the only SANE way to lower your SAC. Even then, we have to realize that the SAC is not some esoteric goal, but a tool to be able to calculate how deep for how long. My Cobra does a great job of calculating this for every dive, so I don't have to do the math. I do look at it, just to make sure that I am consistent.
BTW, hats off to Roaky for a stunningly good job on the description of the calculations... I hope you don't mind if I put that in my scrap book to use when others ask.
Pete... you are right... and it is important to point this out....
Pejorative terms like *hoover* cause some folks to try conserving air to shake the label... sometimes in unhealthy ways...
Questions like, "How much air do you have left?" can really be a less than subtle form of competition and coerce divers into dangerous and non-sensical practices to *win*...
As you found when folks forget about *conserving* gas and just use the gas as intended they actually end up improving their SAC.
SAC is, as you said, a tool for gas management.
BTW... girly girls usually use less than burly boys because of lung size and muscle mass.... so next time someone wants to brag about their SAC on here we'll just
and nod at one another...
100days-a-year
Contributor
Divesherpa,probly has something to do with the type of diving you're doin' My first dive with doubles+stages and in a new environment over doubled my normal SAC .As i got more comfortable it went down but .6 or .7 is really good pushing 300cuft of gas.I predive meditate and plan ,plan ,plan when gas could be an issue.For OW I meditate when spearfishing lobstering or some other task.When diving OW with others I play a lot so I burn a lot.NetDoc hit the proverbial nail with his reply about cardiovascular conditioning.
Stone
Contributor
A: Depends
If you're diving air deeper than ~70 fsw, or EANx32 deeper than ~90 fsw, you don't need a SAC any better than ~.6 because it's the NDL that sends you home.
Where I dive (80-100 fsw) you can have a SAC of .2 and you'll still be getting on the boat with the "average guys"
If you're diving air deeper than ~70 fsw, or EANx32 deeper than ~90 fsw, you don't need a SAC any better than ~.6 because it's the NDL that sends you home.
Where I dive (80-100 fsw) you can have a SAC of .2 and you'll still be getting on the boat with the "average guys"
100days-a-year
Contributor
Stone,I dive LP95s jacked -up to 3000+ and occasionally doubles.My limiting factors are "how bored will I get hangin there"Even with deco gas it can be critical to planning.With an AL80 on air I reach deco 1st from 90ft down due a lo SAC.Less consumtion is better for me.But I agree that competitiveness shouldn't cause problems.Good-natured jibing is normal,but it has to be good-natured and reciprocally accepted.I run,lift weights,bicycle,kayak and have a strenous job(when I work)This keeps me fit and lowers my SAC.My buddies mostly don't have the same cardio fitness so they burn more .Our turn time is usually due to the boredom factor rather than air consumption or NDLs.I really like having that freedom.
)This keeps me fit and lowers my SAC.My buddies mostly don't have the same cardio fitness so they burn more .Our turn time is usually due to the boredom factor rather than air consumption or NDLs.I really like having that freedom.donacheson
Contributor
Well said, Doc.
Similar threads
