[PSUBS-MAILIST] ABS Hull Calc

[Jon Wallace via Personal_Submersibles]

You have to put in some kind of value and as I recall, very small 
numbers can come up with some weird results.  If you use 36" OD, 72" 
length, and .25" thickness for the shell, and then enter .1" for the 
stiffeners, you'll see that the bottom line calculation (line 92) is a 
max depth of 1 foot.  However, if you look at line 51 which is the 
maximum Pa for inter-stiffener strength you'll note that it is 61.2 psi 
which matches the results of the unstiffened online calculator.  Note 
that both of these results correspond to a "n" of .8 which you can 
manipulate in the excel spreadsheet but is hard-wired in the unstiffened 
calculator.

So I think the answer is that you have to use very small number for 
lines 18 through 21 (try .001) but ignore line 92 and find the lowest Pa 
between lines 51, 56, 63, and 71 to determine the maximum allowable 
operating pressure.

Jon




On 4/23/2014 7:02 PM, Pete Niedermayr via Personal_Submersibles wrote:
> What do I enter if I don't want to have hull stiffners. I want to compare results with the Psubs online calculator
>
> Thanks Pete
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