[Rhodes22-list] Roger!!

[Peter Nyberg]

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
>