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I've decided to figure out what my SAC is. As far as I can figure out the maths are;
Air In - Air Out x Size of cylinder / Average Depth / Dive Time

Soooo, after cheking my poorly maintained log book I've came up with this;
220bar - 50bar x 12.2ltrs / 16av. dep. / 53mins.

This equals = 2.44 lts. per min.

I'd gather this is wrong by a long shot. Anyone point out where I'm going wrong?

Peter
 

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A short fat well off crap cave diver. Likes wrecks
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Cylinder size 12.2 220 bar is:

12.2X 220= 2684ltrs of gas

50 bar left is:

50 X 12.2=610 ltrs of gas left

Total usage is:

2684 - 610 = 2014ltrs in 53mins

Depth was 16m which is 2.6bar so:

2014 devided by 2.6 = 774.6

774.6 devided by the time 53mins = SAC

SAC = 14.6   (15 lpm)

Does that make more sence?

ATB

Mark Chase
 

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Okay:
220bar - 50bar = 170bar
170 bar x 12.2ltrs =2074 litres
Av depth = 16m = 2.6bar
2074 / 2.6 = 797.7
797.7 / 53 = 15l/min

You DID convert depth from 16m into 2.6 bar... didn't you..?
 

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Grumbler-chief in Residence
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Hi,

Average depth in bar so 16M becomes 2.6bar

Andrew

This was a race and I lost
 but Howard was even slower
 

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That's Dude with an E
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Depth = depth in Atms or bar which gives you a SAC of about 15

added

Andy, so did l
 

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Just not enough dive time.
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Mark
[b said:
Quote[/b] ]2684 - 610 = 2614ltrs in 53mins
Not quite, I made it 2074ltrs

which is why your SAC cals are slightly wrong mate.
I agree with 15 (ish) l/min
Regards
Matt
 

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The Artist formerly known as 'Kirky'
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Sorry to be a prat but what does SAC stand for??

I calculated mine and for a few dives it is between 16 and 25. Is this good or bad or what
??
 

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DUE CEO, Booking agent, Coffee maker & Dogsbody...
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Well i got to this one far to late


Don't you just love doing these sums


SAC = Surface Air Consumption. X the depth in bar for your air requirements so:-

20l/min Surface / 1 Bar
40l/min at 10m / 2 Bar
60l/min at 20m / 3 Bar
80l/min at 30m / 4 Bar

16l/min is good, 25l/min is a good average that is generaly used as a start figure when teaching. I dived with Alan a while ago and i think his was about 2l/min.

The rate is very dependant on task loading though. Drifting it should come right down, physical work, brass fever, it will go up, poor vis, deeper than usual, it will go up. Deco stop it should come down, holding onto a shot in a strong current - may well go up.

Diving with me - Through the roof.

Dive Safe

Paul
 

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<font color='#0000FF'>All your answers are WRONG , it's less than 15 lt's a min ,, more like 13.....




What about taking away air used for buoyancy...my suit and wing has it's own air source, so all my back gas i can use for staying down longer.


i do hate being picky,,,,,,,

PETE K , do an averag over 10 or 20 dives , mate , that will then give you a better average  for future dive planning.

Andy

Btw ,my average is very small,,,,,this month 7.2 ,,,,,,, but i am a smoker ,lungs filled with crap , so less air to suck
 

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A short fat well off crap cave diver. Likes wrecks
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[b said:
Quote[/b] (MATTBIN @ Oct. 07 2003,17:24)]Mark
[b said:
Quote[/b] ]2684 - 610 = 2614ltrs in 53mins
Not quite, I made it 2074ltrs

which is why your SAC cals are slightly wrong mate.
I agree with 15 (ish) l/min
Regards
Matt
Yes quite right, sorry for the typo.

ATB

Mark Chase
 

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Discussion Starter · #11 ·
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Thanks guy. I'll go to the back of the class now and put the big, white pointy hat on.

Peter
PS-I see where I was going wrong. I was dividing by 16 and not 2.6.
 
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