Re: [PSUBS-MAILIST] Nice Sub Bill!

[Phil Nuytten <72020.572@compuserve.com>]

Hi, Bill:
        Just as a guide . . . for your mild steel 15' X 46" X .27 hull -
the calculated depth before the hull  turns into a halibut from assymetric
buckling is:
Unstiffened: 100 feet
Single stiffener: ( unsupported section = 90"): 200 feet
Three stiffeners, ( unsupported section= 45") 400  feet
Cut these approximate values in half to get the safe working depth . . with
no stiffeners you're looking at 50 feet and so on.If you can't afford the
space inside, put them externally - but remember to cap the perpendicular
with a flat band so that you have a 'T' section. If you want to avoid
either a doubler ( the traditional fix) under your 'conning tower' or a
series of gussets, you can put a wide horseshoe - shaped stiffener right in
the 'V' - so the stiffener is at 1:30 if the side of the 'conning tower' is
12:00 and the flat of the hull is 3:00 (  assuming that your trunk ends in
a point on each side of the hull.) By the way, a 46" dia. hull by 15' is
pretty big.  A more usual length is 10 - 12' What's goin' in there besides
you?
Phil Nuytten