Physics of diving question...

[JointVentureDive]

DETECTOR GUY....    THANK YOU....  FINALLY,  SOME REAL  SCUBA RELATED DISCUSSION.   THANK GOD. I was about to think we only discussed coffee beans here and occassionally look at some of John J. great video's.  (WHICH I REALLY LIKED)  Would love to have more scuba related discussion in here.

Is this class you are taking Advanced Nitrox and Deco proceedures? 

I agree with most of what Hydro said, and Everything Smith Diving said.  I might just add one or two things.

You are over thinking this.  I don't think the instructor would want you to know the answers to this.  Infact, they probably would think you are being anal.  But. that being said, and off my chest,  .... Why would you want to even get close to the tissue compartment over saturation risk or want to know the specifics of this.  You always take the worst possible case of saturation, half it  and that is your maximum length of your dive when depth and time is factored. 

In otherwords, never exceed it and that is going to be the maximum length of time with deco time included and  assumed that you will make on that dive.  You can simply rely on your computer or actual panned dive if you are using your Navy dive tables. They work.  The only time they don't work is when someone does the math wrong and its pretty hard to do that, seeing its already done.   But I do know some people like to slide they're fingers down, when they are supposed to move them over.   Gosh, that sounds riske, but you know what I mean.

The computer is so darn accuate on these things.  And even if I did the math on a planned dive, and my computer said its time to go, but my math said it I could be at depth longer etc, I would rely on my computer, get out, because in the end, why would you argue with your computer.  Trust it.  EVERYONE SHOULD DIVE WITH COMPUTERS and I personally believe every certified diver should have one.

Your next possible dive will be determined by the "theoretical surface interval time."  Never exceed you Max M value on your lowest compartment (or fastest saturated compartment). or Simply put don't violate the Surface Interval Time.     You don't need to know the specifics.  Others have already died for us and the studies behind the theory is pretty sound as I understand it.  oH, AND GOD FORBID YOU DIE,  THEY ARE GOING TO SAY YOU DROWNED ANYWAY.   "Not his tissue compartment was over saturated with Nitrogen and he exceed the limits."   

This past Nov.'2009,  IN FLORIDA,  4  REBREATHER DIVERS DIED in 3 different instances.  Obviously they didn't drown but I'm sure thats what it will be written up as, instead of equipment failure as is most of the cases, or operator error in selecting the wrong gas mix for the kind of dive they are doing which is probably what happened to the 2 Rebreather divers that died together.

I think in the very first books we all started with be PADI, SDI/TDI  NAUI,or SSI etc, they clearly said something to the effect that it is.... INFACT, ALL THEORETICAL and that it is not an exact science.  The Navy dive tables and Dr. Haldane theory was just that, and it actual saturation compartments are different in everyone.  SIZE, SHAPE, and Gas's used as well as consumption rate of the gas, and the Nitrogen loading, and lets not forget  max depth and time at depth will effect us all differently.  Skinny, vs. fat, etc.  short stature, vs. Tall and lets not forget actual body health and condition.  Alcohol, asprins, all are variables in satuation rates and will change from month to month and physical metobolic rate.and a womens time of the month would also be a factor. 

Now as far as saturation, yes there are many studies and facts behind the tables they have done with with Many navy divers and other ginea pigs, but the bottom line here for recreational divers is use your tables, and rely on your computers.  The bottom line for tech divers is use the tables and rely on your computers. If your mixing gases, YOU BETTER RELY ON YOUR MATH...    All the work has been done for you.  Plan you dive, check it twice and enjoy the dive.  Follow your computers commands.  ...      I'm sorry Dave, I can't do that.... 

And to comment on Arcflash.,  If you are OOA,  your only option (assumes no buddy and no back up and you are OOA) is to SURFACE..  I'd rather take the chance of getting a decompression hit, and get help, rather then to learn how to breath water through my gills.    LOL.

I do have nice gills'  but they can't make O2 yet.   In fact they tend to take peoples air away so you'd really be in big trouble if you were diving watching me. 

BUT THEN AGAIN,  I'M A GREAT BUDDY, AND I WOULD NEVER LEAVE MY BUDDY WITH AN OOA.  We would have been reviewing this all along, AKA   BUDDY CHECKS...and we would be on the surface with plenty of air left in our tanks as per the plan.  Unlike an account I read about in a certain mine pit in Northern Minnesota about buddies.

LAST BUT NOT LEAST
Another sore spot in my ...(well I won't say) is why do we have to pay for a full tank of air up here if we still have 6 -to 800 pounds of air left.  In Florida some shops are charging by the actual gas required to fill the tank to say 3000 pounds.  Avg. fill is a couple bucks cheaper this way in Florida.  One shop owner told me that they are starting to do this, because, it gives the shop owner, and his insurance company, a partial out of a law suit if the air is found to be bad air, because, other air was mixed with the new air etc.  (does that make sense)  way to much litigation. 

Nicki