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[PSUBS-MAILIST] Is 14.7 lbs per sq in (1 atm) subjective or an absolute?



Recently I read a post that said hull reinforcement hoops should be no more out of round than 1/8th of an inch.
 
How safe would they be if they were out of round by 1/4 of an inch? It wouldn't really matter would it because 1/4th of an inch is
 
"close to"  1/8th isn't it? How about if they were out by 1 inch? That would be ok wouldn't it because I consider 1/8th of an inch to be "close to" 1 inch
 
Do we really need to measure a hull mathematically? Can't we just look at it and say..."that looks close enough"?
 
How about if we leave a few air bubbles in our oil compensated electric motors? It won't matter will it because they were "close to" being devoid of air?
 
 
Please don't take my above questions seriously. I am simply making a point.
 
It is puzzling to me that builders rely so much on math to build pressure hull subs, and are very specific in their math because if they are not
 
they might wind up crushed from implosion. Yet we seem to readily accept that "close to" one atm is the same as 1 atm and we continue for some
 
unknown reason to accept and continue the term "1 atm sub" even when we know it is not always mathematically accurate in describing the true interior atmospheric pressure
 
within a given sub. Are we just so used to the term (1 atm) that it is comfortable or something to us even if inaccurate? Are we too lazy to change it to an
 
accurate mathematical description? Are we intimidated by the wealth of books that use the term inaccurate or not? Are we afraid of being ridiculed if we take a stand for
 
accuracy in mathematical measurements of pressure? We can mathematically calculate the distance from the earth to the sun. We can use math to tell us what the gravitational pull of the moons of jupiter are,
 
yet we continue to say a subs atmosphere is 1 atm (14.7 lbs per sq in) when we know in the case of the Hunley it is not, and as I have been told by other members, it frequently is not with other so called 1 atm subs.
 
Do we as humans resist change and just want to shove this term's mathematical inaccuracy under the carpet and pretend it does not exist because it takes effort to make a new term?
 
I can almost hear Edward G. Robinson in the movie "The Ten Commandments" saying to Charleston Heston...."Where's your math god now Moses?"
 
Kindest regards,
 
Bill Akins.