Most of tec divers I have seen use one AL-80 with 80%-100% O2 for the last stop, based in that 50% of those 11L tank is for the Diver and the other 50% for your buddy or in case of an accidental (SHTV) over run of the plan.
Then I see the thread over buddy breathing, which we all were taught how to do, I guess mainly because carrying two AL-80 / 11L is cumbersome, but almost implicitly in a course they never talk about carrying two AL-40 / 5.6L or 7L bottles when you are doing the training.
I see a lot more advantage on carrying two 7L bottles as they are just little thicker than the AL-40 than carry one big AL-80.
Two 7L adds so much redundancy even more if both you and your buddy use them that it will virtually impossible to miss your Deco or be in the need of buddy breathing.
Is this a general training approach that in the course they directly go over buddy breathing an not pointing out other options, rather than use what is left of your 50% go to back gas and buddy breath.???
It seem logical that starting with even one 7L bottle ( if money is an issue ) will allow you to do baby steps in to Deco diving to a point that when you do bigger dives you buy your second 7L bottle, because the next big step will be two 11L bottles, but breathing out one complete 11L tank will put you in to CNS range issues anyway.
I currently only own one AL-40 bottle which I always keep with 50%, and when money is available I was thinking in a 7L rather than a AL-80 / 11L for 80% O2, and if later possible a second 7L bottle.
Then I see the thread over buddy breathing, which we all were taught how to do, I guess mainly because carrying two AL-80 / 11L is cumbersome, but almost implicitly in a course they never talk about carrying two AL-40 / 5.6L or 7L bottles when you are doing the training.
I see a lot more advantage on carrying two 7L bottles as they are just little thicker than the AL-40 than carry one big AL-80.
Two 7L adds so much redundancy even more if both you and your buddy use them that it will virtually impossible to miss your Deco or be in the need of buddy breathing.
Is this a general training approach that in the course they directly go over buddy breathing an not pointing out other options, rather than use what is left of your 50% go to back gas and buddy breath.???
It seem logical that starting with even one 7L bottle ( if money is an issue ) will allow you to do baby steps in to Deco diving to a point that when you do bigger dives you buy your second 7L bottle, because the next big step will be two 11L bottles, but breathing out one complete 11L tank will put you in to CNS range issues anyway.
I currently only own one AL-40 bottle which I always keep with 50%, and when money is available I was thinking in a 7L rather than a AL-80 / 11L for 80% O2, and if later possible a second 7L bottle.
