[Member-Forum] Moment of Inertia

[Jon Wallace]

Hi Joe,

I don't recall ever seeing a rule of thumb for t-ribs.  The hull 
calculator worksheet on the website will let you see how rib dimensions 
affect the strength of the hull.  Sean Stevenson once gave a good 
explanation of the relationship between the hull and ribs but I can't 
find that email at the moment.  In general, and this is REALLY just a 
general statement, my experience with the hull calculator has shown that 
ribs of the same thickness as the hull, 4 times thickness for the web, 
and 6 times thickness for the flange, are appropriate.  That may not 
produce ideal results in every instance, but for conceptual 
rule-of-thumb it should be adequate.

Jon


On 3/25/2014 10:10 AM, Joe Perkel wrote:
> Hi Paul,
>
> The question is anecdotal based on an off the cuff thought of upsizing 
> the shell O.D. to 42" from 36". I am very hesitant to do this do to 
> weight and handling issues however, several members have made a 
> compelling rationale r/t simple comfort. At 53 I'm 6' 190 lbs and 
> should expect that L to W ratio to change by build time!
>
> I have to think a bit about the shell thickness r/t welding and 
> corrosion issues, but Depth no more than 350'. I seem to remember a 
> cross section drawing of a T section somewhere with a simple L/W/H 
> relationship to shell T, but can't find it again.
>
> I'll take that pdf if you don't mind. I'm not at home and won't be 
> until later this week to do some number crunching.
>
> Thanks Paul!
>
>
> Joe
>
> Sent from Yahoo Mail for iPad <http://overview.mail.yahoo.com?.src=iOS>
>
>
> ------------------------------------------------------------------------
> **

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