Roger,

Welcome back to the list. Your expertise has been missed.

Stephen Staum
s/v Carol Lee 2
Needham, MA

On Mon, Nov 26, 2018 at 12:52 PM Peter Nyberg <peter at sunnybeeches.com>
wrote:

> Roger,
>
> I joined the list well after you stopped posting, but I feel I know you
> from having spent many hours reading the list archives.  I’m very happy to
> see you posting once again.  I hope the list can look forward to more of
> your insights in the future.
>
> Peter Nyberg
> Coventry, CT
> s/v Silverheelsl (1988/2016)
>
>
> > On Nov 26, 2018, at 12:02 PM, ROGER PIHLAJA <roger_pihlaja at msn.com>
> wrote:
> >
> > Bob,
> >
> >
> >
> > I just took some rough measurements of the curvature of your rudder from
> the attached picture.  It is deflecting ~1.5% in compression buckling
> mode.  The rudder blade is made from glass fiber reinforced polyester (FRP)
> with some internal ballast.  Typical FRP composites have an ultimate
> elongation of from 2-7%, with the failure point tending towards the low end
> as the temperature drops because the plastic resin passes thru its glass
> transition temperature and becomes brittle.  I would NOT leave the rudder
> loaded like that all winter.  You have another issue in that the
> compression on the rudder is loading up the rudder’s gudgeons and pintles
> and the boat’s transom in a manner they were never designed to handle.  By
> spring, you may very well have hull damage on the transom.  I would find
> some way to get that rudder unloaded ASAP!
> >
> >
> >
> > If you unload it soon, you should see the rudder blade straighten out.
> At your next opportunity, strip the bottom paint off the rudder and
> carefully inspect it.  You are looking for tiny transverse cracks (i.e.
> running from side to side vs. the length of the rudder blade), especially
> on the port side where the surface was in tension due to the buckling.  If
> you see these cracks, you might consider prepping the surface and applying
> a couple of coats of WEST System epoxy to both sides of the rudder blade.
> >
> >
> >
> > Let me know how it turns out for you or if you have any other questions.
> >
> >
> >
> > Roger Pihlaja
> >
> > SV Dynamic Equilibrium
> >
>
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-- 
Stephen Staum
Pariser Industries, Inc.