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Basic Scuba DiscussionsHave a Scuba related question? Get a Scuba related answer here. Please note: This forum has special rules. This forum is intended to be a very friendly, "flame free zone" where divers of any skill level may ask questions about basic scuba topics without fear of being accosted. Please show respect and courtesy at all times. Remember that the inquirer is looking for answers that they can understand. This is a learning zone and consequently, any off-topic or overly harsh responses will be removed.
So many time i get asked . Whats the best ascent rate. .
Simply in diving everything should be done slow. Its a none competitive sport.
Your Descent and ascent should be slow. as so should be your dive.
Some organizations have different ascent rate . Some 18 mts per min and some 9.
the slower the better to allow the N2 those micro bobbles to exchange.
gauge not working! come up on the smallest bubbles. It should take 60 sec to rise 10 mts. An average dive computer works on that rate 10 mts per min.
However . If you the 18 Mtr per min trained. and got it in you head this is what you do. the if your down deeper the 10 mts.
Come up to the last 10 mts no more then 18 mts per min. Then slow it down even more to 9 Mts per min. Do your safety stop. and air allowing take as long as you can. to go from 5 mts to the surface. TO MANY DIVERS THINK THAT BECAUSE THEY HAVE DONE A SAFETY STOP > THEY CAN GO TO THE SURFACE RIGHT AWAY. NO NO NO!
Slow it down even more. More so after a deep dive and if your a bigger person. Or been working or swimming into currents.
remember to calculate you air . come up with 100 bar or more. See dive profile.
Never exceed your dive tables And watch your dive computer. This applies more so in cold waters. or at Altitude.
I am not a tech diver. However I hold a Nitrox ANDI and Did much of my diving in the UK . Where I dive in borneo little need for tech diving. However . Common sense
and the above should be kept in mind. Ascend slow as you can air allowing. as a Guide you should be at 50 bar between 6 mts and the surface . no less. 50 bar on a relaxed dive then will last at 5 mts quite along time depending on your breathing rate. Just because your on 50 bar , does not mean stressing your self wondering have you got enough or you in the red line. Yes I have divers who get worried when they get 50 bar or lower. Just relax! make your way to 5 mts to do that safety stop Ask me more.
So many time i get asked . Whats the best ascent rate. .
Simply in diving everything should be done slow. Its a none competitive sport.
Your Descent and ascent should be slow. as so should be your dive.
Some organizations have different ascent rate . Some 18 mts per min and some 9.
the slower the better to allow the N2 those micro bobbles to exchange.
This is too simplistic a summary of correct ascent rates. There is a lot of debate about correct ascent rates and I have been told that slower is not always better if you are very deep as you might still be ongassing. There are arguments that ascent rates should be varied based on depth. Some agencies recommend an even slower ascent for the last five metres. Basically you need to work out the correct ascent rate for you and it might not be the same for everyone.
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remember to calculate you air . come up with 100 bar or more. See dive profile.
I would find for every dive that I have done so far, 100 bar would be too conservative given my SAC and the size of the tanks that I use. Some dives I come up with as little as 10 bar - say when I am diving under a shallow pier. Others may be different but you cannot generalise about how much air one should ascend with.
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Never exceed your dive tables And watch your dive computer. This applies more so in cold waters. or at Altitude.
Why does it apply more so in cold water/altitude? One should never exceed their limits regardless of where they are. Also not everyone uses a dive computer.
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and the above should be kept in mind. Ascend slow as you can air allowing. as a Guide you should be at 50 bar between 6 mts and the surface . no less. 50 bar on a relaxed dive then will last at 5 mts quite along time depending on your breathing rate. Just because your on 50 bar , does not mean stressing your self wondering have you got enough or you in the red line. Yes I have divers who get worried when they get 50 bar or lower. Just relax! make your way to 5 mts to do that safety stop Ask me more.
So come up with 50 bar or 100 bar? Less than 50 bar? Either way, it is too simplistic to use such figures for everyone.
I know you are trying to be helpful but your post is confusing and you generalise too much.
I heard the 18m/60ft per minute came from a split decision between the US Navy who were arguing for a 9m/30ft per minute ascent rate and the Army who wanted a standard 100ft/30m per minute - they were both told it was 18m/60ft and now would everybody shut up!
Nice story - whether it's true or not is irrelevant - what is certainly true is that it's not based on any kind of science. There was a link posted on here recently (I can't find it) showing the difference between different ascent rates conducted on different dives with different safety stops. The actual article was about the merits of adding a stop for 1 minute at 15 metres during ascent.
Whilst I can't remember all the data offhand what it did show is that there is very little significant difference in Nitrogen loss between different ascent rates. In fact in certain cases, the 9m per minute ascent rate was *less* beneficial to the amount of Nitrogen that was lost. The most important factor in all ascents was the safety stop at 5 metres.
I agree that there is some good sense and conservatism in your arguments, but it is a bit too general for all dives. Why start to make my ascent with 100 bar if I'm diving in 18 metres of water? Okay - 50 bar at the surface is very sensible and very conservative and some dive shops very wisely make it a 'rule'; it's a good safety margin for the average holiday diver, but I'm not too worried if people under my supervision run beyond that if necessary.
This is, however a forum for basic scuba discussions and some good points are made - things like divers rushing up from their safety stops for example - I've seen that happen a fair few times!
Your Descent and ascent should be slow. as so should be your dive.
I know this is not what the thread is about but why should the descent be slow? I usually try to get down to the reef as quickly as my ears allow me as I'd rather spend time enjoying the reef than to spend time getting to the reef.
That is just my preference but there are certain times when it is imperative that we descend quickly. When there is a strong surface current for instance, we want to hit the correct spot on the bottom and not be swept away while we're casually descending. We basically just duck dive and start finning something silly so we can get down as quickly as possible.
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If it ain't broke, then you need to fix your grammar.
This member has said "Thank you." to Deefstes for this useful post:
I must say this was one of the toughest posts to interperet because of the lack of properly used capitalization, grammar, punctuation and spelling. I say this only because you may still be able to edit it so that it is understandable.
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"It is better to remain silent and be thought a fool, than to open your mouth and remove all doubt." - Abraham Lincoln
I must say this was one of the toughest posts to interperet because of the lack of properly used capitalization, grammar, punctuation and spelling. I say this only because you may still be able to edit it so that it is understandable.
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Perfection is achieved, not when there is nothing left to add, but when there is nothing left to take away -
Antoine de Saint-Exupéry
Hey maged.....I like your AV. Here is a little something in line with it .
And, I wear the "Grammar Police" badge proudly but only show it when the offending post really was an abuse of the English language and if I verged on getting as headache simply from trying to figure out what the post was saying. For small errors or ommissions the badge stays in the pocket .
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"It is better to remain silent and be thought a fool, than to open your mouth and remove all doubt." - Abraham Lincoln
I would find for every dive that I have done so far, 100 bar would be too conservative given my SAC and the size of the tanks that I use. Some dives I come up with as little as 10 bar - say when I am diving under a shallow pier. Others may be different but you cannot generalise about how much air one should ascend with. 
Doc Adelman 
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