On Tue, 9 Dec 2008 09:41:20 -0800 (PST), andy
wrote:

Is your approach based on ease of allignment or strength issues? I
evision corrosion problems where the weld does not completely
penetrate the slot. Upon typing this It is no worse (void penetration
wise) than my original approach with slotted shafts.

It sounds like you're concerned about crevice corrosion, and rightly
so. As long as your welds are sound and prevent water from entering
and stagnating in small cavities you'l be OK.

I don't know what the current thinking is on plate rudders. I built a
few large rudders about 25 years ago and I believe the design was
based on research from the University of Maine. There was fairing
added around the rudder post (it was the full length of the rudder), a
flange at the top and bottom, and a wedge cross-section at the
trailing edge. These modifications were supposed to decrease drag and
increase effectiveness without making the fabrication overly
complicated. If you're interested I can make a quick picture.

(Say hi to Rex for me if you see him. He doesn't answer my emails.
g)

--
Ned Simmons