Mailing List Archive Mailing List Archive
gmiiii@in*.co* wrote: > Sorry , Rich, I forgot what room temperature is in Hawaii. Heimann has a >physics degree from Harvard, he works for Oracle Systems in an extremely >technical job, and used to dive with the WKPP, so the fact that he uses none of >these resources always amazes me - maybe I should give him Bill Dooley's phone >humber. - G Chief, you are a very intelligent guy, which is why I listen to you. You were undoubtably one of the smartest at UNC, and maybe also at Dean-Whitter, so you probably didn't get your assumptions challenged a lot. At Harvard, and also at Oracle, there are so many smart people that I learned always to question assumptions. E.g., what the hell does "depth" mean on a table or gauge? You are right when you say that I shouldn't go looking for the answer on this list. The real issue is that the meaning of "depth" in both tables and gauges designed for altitude use isn't always obvious. For example, the Uwatec digital depth gauge instruction sheet simply says that the unit displays correct depth, even at altitude. What the hell does this mean? Real correct depth, as measured by shotline, or "depth" as measured by absolute pressure, which is what is physiologically important? The Aladin Pro instructions say that the computer adapts to altitude, whatever that means. Even worse, different tables have different meanings for depth. The Buhlmann-Hahn high altitude tables explicitly say that depths used are those indicated on a gauge calibrated at sea level, NOT a shotline, whereas the DCIEM altitude tables explicitly say that depths are NOT those indicated on a gauge, and they recommend using a shotline. Note that issue this doesn't matter when talking about bottom depth, but could matter a lot for deco. I.e., suppose I am using an analog gauge which is calibrated at sea level, so it reads 4' shallower than I actually am at 7000' altitude. Now if I am using the DCIEM altitude tables, my shallow stop is at 8' by shotline, which is 4' indicated on my gauge. On the other hand if I am using a digital gauge which corrects for depth, then I really should stop at 8' indicated, and if I go up to 4' I could get bent. John ------------------------------------------------------------ John H. Heimann Sr. Product Manager Oracle Corporation Security Products 500 Oracle Pkwy, Box 659410 415-506-9750 (phone) Redwood Shores, CA 94065 415-506-7226 (fax)
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]