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#108
How much air for ascent?
AMkee - 3/29/2013 4:51 PM
Category: New Diver Q&A
Replies: 21

Hey all, doing my first deep dive without being in a class and i just wanted to get a survey of how much air do you say ok its time to head up and have enough for a safety stop and all that. Ill be in around 70’-85’ in the dive. Ive heard someone say they come up at 700. Would love to know what everyone else does. Thanks
#4236
tazzer9797 - 3/29/2013 9:27 PM
Best advice I could give is.. Forget what others say. On your first few deep dive stick to the rule of thirds. No one knows how they will react to the dive. You may breath a lot more do to excitement, scared what ever. After a few deeper dives you can figure out your own air consumption rate and dive your numbers. Remember also to communicate to your dive buddy and visa versa... first one to 2000 PSI calls the dive.. Dive Safe...
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Eric_R - 3/30/2013 3:39 AM
I agree with Tazzer. It follows the rules of plan your dive and dive your plan. All dives should have the same safety considerations no matter what the depth.
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DiveBuddyChgo - 3/30/2013 4:55 AM
Sorry but you should be back in the class Anyways your responsible for you own mistakes. You should be diving at your own level of certification. Don’t trust any other divers opinion not matter how much experience they seem to have. Trust your gut and what your taught in a cert’d scuba class. Your only buddy is your gut and brains. Anything else will kill ya. And no one else needs a law suit when the family reads a posting on your computer. Sorry but its the truth. Now go have fun in another scuba class.
#2194
ScubaGrunt - 3/30/2013 5:41 AM
I concur with tazzers’ recommendation, go with the rule of thirds. Not to insult your intelligence but just in case you don’t know, that’s when you descend using one third of your air, conduct your "bottom time" on one third, and ascend and execute your safety stop with the last third. It’s a good rule of thumb for both beginners and experienced divers alike. Have fun!

Danny
#108
Subscribed
AMkee - 3/30/2013 5:58 AM
Yes, I was planning on the thirds rule. Just thought id ask around. Looks like I won’t be asking anymore questions on this board.
#567
Hapkiman - 3/30/2013 8:44 AM
There are many schools of thought on this bottom time calculation . Assume this You will need enough air to bring you and your partner to the surface safely and this is to include Deco obligations . Your consumption of air during normal breathing ,Your tank size all play into the final calculation . Assuming an emergency uses more gas this is also added in . It will give your "Rock Bottom " time .


Drift dive ,cave dive or wreck will all use a different method as will the depth you are diving . The safest way too do this is dive in thirds until you know how to do the calculations .



I do not use a computer ...... Depth gauge ,SPG and dive watch . Write it down before the dive on a slate or wet notes to refer back to them .



Hal
#20384
LatitudeAdjustment - 3/30/2013 10:34 AM
Did you read http://www.divebuddy.com/forum/26829/accomplished-bad-divers/ about the diver who usually surfaced on someone elses air but not the last time?

Being new your SAC may be higher than those you are diving with so I would leave the bottom with more than you think you’ll need, one third sounds good.

Then there are the times when the whale stuff hits the prop, on a dive in the Texas Flower Gardens on an oil rig with a group of experienced divers who were returning to the boat with the minimum air found the wind was holding the boat 90 degrees to the current. The boat had a Carolina rig down, the current wraped one side line over the prop, the other was pulled way out from the remaining ladder. As 30 divers waited in line for the dash to the ladder a lot of OOA situations began, those who had left with more air and those packing ponies were okay. Many of those divers had ditched their snorkels over the years and now wished they had one, that dive is the reason I have a folding one in my pocket!
#7701
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Nitediver - 3/30/2013 11:30 AM
I think we are missing the point here This is a novice diver. She is doing her first deep dives. Diving from a boat the briefing should include an amount of air they want you to come back on board with. Same for a shore dive. Subtract that amount from your supply whatever is left divide into thirds. Wreck and cave divers use this as a rule of thumb and will work well for you. Assuming a 3000 psi tank and on-board of 500 psi you have 2500 to play so divide by 3. Gives you 833 psi for each phase of your dive. down, around and back. These are estimates and your numbers will differ. Do your own math and remember you can call your dive at any time. Check your tables to ensure you are staying within your NDL limits for the depth and time. Relax, and enjoy. if you have to err do so on the side of caution. Plan your dive, dive your plan. Hope that helps
#14712
tardmaster - 3/30/2013 5:49 PM
Amkee.....Please ask all the questions you want. Just keep in mind some people are just act like "peckerheads" because they think they are are God’s gift to the diving world. i’m asking, as one of the mods on here, to please continue you quest for knowledge and dont let people like that turn you off of this site or the sport for that matter. If you feel you must, ask one of the mods or pros on here.
#4236
tazzer9797 - 3/30/2013 7:29 PM
PLEASE...Never stop asking questions to gain knowledge. No matter what you read or are told. We were all new divers once and had to gain knowledge from some where. Please remember your limits and dive with in them. In no means do I say don’t take classes. That is the main way to learn and learn the right way. Sometimes asking for help on a certain subject is just as good.....So ask away and don’t be shy... This is a great site with lots of great people that know how to dive...Don’t take a couple negative comments to heart.. STAY SAFE
#7701
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Nitediver - 3/30/2013 7:36 PM
AmKee just remember that when you asks questions you not only make you a better diver but the rest of us as well. We as long time divers get complacent and that could get us hurt. You ask a question reminds me to think and then act. Refine my skills and be a better diver. Thanks for the question. ask anytime that’s what the forums are for.
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Greg - 3/31/2013 7:52 AM
From AMkee: Yes, I was planning on the thirds rule. Just thought id ask around. Looks like I won’t be asking anymore questions on this board.

Never stop asking questions. Some people seem to be more direct than others, but dont take anything personal. If they responded to a topic in the New Diver Q&A category, they are probably just trying to help. If anyone said anything bad to you, let me know and I will kick them off myself.

Btw, I agree with a couple responses so far. The rule of thirds is a good plan to start with...but its always up to other circumstances...like equipment failures, water temp and current, buddy ability, etc.

Just plan the dive well, stick with the plan, and be prepared for alternate plans.
#108
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AMkee - 3/31/2013 8:50 PM
Thanks for the support! I had an amazing dive. Planned my dive and dove my plan.
#7701
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Nitediver - 3/31/2013 9:04 PM
Glad you had a great time.
#2194
ScubaGrunt - 4/01/2013 4:36 AM
I’m glad you had a good dive AMkee and I hope you continue to use the site. It has been a great resource for me and I’m sure it will be in the future as well.
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madlobster - 4/01/2013 8:10 AM
Hang in there AMkee, good bunch here, some more direct than others. Glad you did and enjoyed!!
#85
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mtopper - 4/01/2013 4:19 PM
Hey AMkee - I think I may have mentioned to you that I took a trip out of San Diego to dive the kelp beds. The first dive at Green Tank was around 80 feet and my brother and I agreed on the rule of thirds since this was to be the deepest dive of our dive careers. Once either of us hit 1000 PSI we began our ascent. I think we ended the dive somewhere around 600/700 PSI. We just took it slow coming up. It was nice knowing we had plenty of air especially at those depths. Be safe and looking forward to diving Laguna with you real soon! :)
#4853
Granitehawk - 4/02/2013 3:33 PM
The instructor i was trained under said try to do thirds, one third swim out, one third swim back and a third for the ascent.
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John_giu - 4/06/2013 1:35 PM
you might be surprise how much more air you suck at 80+ feet.

Get a good fill 3200 lbs in an 80 cubic foot tank. Quit at 1500 psi

and take your time on the way up. Two dollars of air ain’t worth your life.

You can play it closer after a few dives.



In North Atlantic diving we require doubles or a pony bottle. Just about every year we

get an out of air dead diver. A pony rig or SPARE AIR is a good investment.