PavoDive:
Whoa guys!! came up with this idea:
What if we installed a microchip in the tank that "tells" the SPG/computer the tank's volume and doesn't show you pressure, but volume (with the proper conversions, of course)??
Does anybody know a good, cheap patent lawyer??
Gio.
The problem with measuring the volume of air in your tank is the fact that the volume in the tank never changes. You would need to know the tank volume and monitor the pressure in the tank to give a proper volume at use pressure calculation.
However, the information that is truly important is how many more minutes of air you have at the current depth and breathing rate. This information is something current air integrated computers can give you.
Teaching volume management during OW would be overwhelming for any student with lots of other things to worry about. You simplify the situation by standardizing tank size (Al 80) and teach the student to recognize and deal with the quantity their gauges are measuring directly - pressure. You wouldn't want an OW student, who can't even stay neutral, to be doing calculations on a table or slate underwater, trying to convert their current tank pressure into a breathable volume.
I just took my OW this summer and I definitely would have been overwhelmed by it, and I'm an engineer. I understand the idea that 500 psi on the surface is different than 500 psi at 100 fsw, so doing a volume conversion to prove or quantify that fact isn't going to help me understand that concept.
Gas management, or at least SAC rate calculation, is being taught to me for my Deep Diving class as part of my AOW that I'm currently taking through SSI. Deep Diving is where this concept most applies and the student should be advanced enough to be able to include this task along with other concerns.