Post by duckbill on Sept 8, 2005 23:30:01 GMT -8
Hello RMannix,
Thanks again for all the work you have done to make such an important tool available.
A couple of things came to my mind as I read the text.
First, about breathing techniques: "DON'T try to consciously control your breathing, or practice "skip breathing". You'll just get winded at best (and possibly panic), an air embolism at worst. Breathe normally,". (Everybody has an opinion on this one, so I don't need anyone "flaming" me for what I'm about to say here.) It is definitely and obviously true that one should never stop breathing while breathing compressed air at depth, but HOW one breathes can have a profound affect on air consumption. Once the diver has had sufficient experience to feel comfortable underwater, this technique can be tried and is effective and safe. First, remember that your airway is comprised not only of your lungs, but also includes your mouth and trachea. Since no significant exchange of gasses takes place in the mouth or trachea, any oxygen standing there is wasted. In order to get a higher proportion of useable to unuseable oxygen in your system for any one breath, it is logical to inflate the LUNGS as much as comfortably possible rather than to breath normally. Breathing normally is fine in everyday surface living where we are free to waste oxygen at will, but oxygen should be conserved as much as possible while using SCUBA, unless you are going to max your bottom time anyhow.
So, number one- breathe deeply.
Number two- With all of that useable oxygen sitting in your lungs, why blow it all out right away? Make a little circle with your lips and exhale s-l-o-w-l-y. The longer the oxygen is in your lungs, more oxygen will be absorbed. As long as you are not doing something strenuous which demands more carbon dioxide disposal, allow your body the time to absorb the oxygen as much as possible. Two things to keep in mind to do this safely: You should never feel out-of-breath or light-headed, and never hold your breath (i.e. block the airway).
Using this breathing method has lessened my air consumption considerably by safely utilizing oxygen to the maximum degree.
Second: "Most (but not all) steel tanks require a 10% overfill to achieve the manufacturer's stated capacity. This is indicated by a plus sign (+) appended to the hydro date. As of this writing (and has been so for a long time) no tank should be overfilled after the first hydro has expired, and no new hydro date will have a plus sign. You must now plan your dives with 90% of the capacity or get a new tank."
The latter portion is simply not true. The plus rating can always be calculated and assigned to the tank as long as it originally was plussed by the manufacturer. Thankfully, my hydro shop is willing to do this, and does so all the time. Most hydro guys don't want to bother looking up the specs or taking the time to do the calculations.
Anyhow, take it or leave it. It's nice to know I'm not the only SAC-rate user out there! I don't know how a dive can really be planned without using SAC.
Thanks again.
Thanks again for all the work you have done to make such an important tool available.
A couple of things came to my mind as I read the text.
First, about breathing techniques: "DON'T try to consciously control your breathing, or practice "skip breathing". You'll just get winded at best (and possibly panic), an air embolism at worst. Breathe normally,". (Everybody has an opinion on this one, so I don't need anyone "flaming" me for what I'm about to say here.) It is definitely and obviously true that one should never stop breathing while breathing compressed air at depth, but HOW one breathes can have a profound affect on air consumption. Once the diver has had sufficient experience to feel comfortable underwater, this technique can be tried and is effective and safe. First, remember that your airway is comprised not only of your lungs, but also includes your mouth and trachea. Since no significant exchange of gasses takes place in the mouth or trachea, any oxygen standing there is wasted. In order to get a higher proportion of useable to unuseable oxygen in your system for any one breath, it is logical to inflate the LUNGS as much as comfortably possible rather than to breath normally. Breathing normally is fine in everyday surface living where we are free to waste oxygen at will, but oxygen should be conserved as much as possible while using SCUBA, unless you are going to max your bottom time anyhow.
So, number one- breathe deeply.
Number two- With all of that useable oxygen sitting in your lungs, why blow it all out right away? Make a little circle with your lips and exhale s-l-o-w-l-y. The longer the oxygen is in your lungs, more oxygen will be absorbed. As long as you are not doing something strenuous which demands more carbon dioxide disposal, allow your body the time to absorb the oxygen as much as possible. Two things to keep in mind to do this safely: You should never feel out-of-breath or light-headed, and never hold your breath (i.e. block the airway).
Using this breathing method has lessened my air consumption considerably by safely utilizing oxygen to the maximum degree.
Second: "Most (but not all) steel tanks require a 10% overfill to achieve the manufacturer's stated capacity. This is indicated by a plus sign (+) appended to the hydro date. As of this writing (and has been so for a long time) no tank should be overfilled after the first hydro has expired, and no new hydro date will have a plus sign. You must now plan your dives with 90% of the capacity or get a new tank."
The latter portion is simply not true. The plus rating can always be calculated and assigned to the tank as long as it originally was plussed by the manufacturer. Thankfully, my hydro shop is willing to do this, and does so all the time. Most hydro guys don't want to bother looking up the specs or taking the time to do the calculations.
Anyhow, take it or leave it. It's nice to know I'm not the only SAC-rate user out there! I don't know how a dive can really be planned without using SAC.
Thanks again.