Rudder Post Construction

[JamesG161]

Does anyone know the materials of construction for the rudder and rudder post for my Hunter 430 1997 or similar size boats in 1995-2002 range or a Hunter rudder design plan?

My guess is FRP coated Alloy 20 Stainless Steel , with same rudder post.
Jim...

 

[Don Lucas]

my 2001 appears to be FRP with a SS outer. That is just wa=hat it appears to be looking at the top when I lib the rack balls

 

[Terry Cox]

Our 1991 P42 is SS.

 

[JamesG161]

I purchased my boat and had some repairs done in Tampa. I have the pictures of before and after the new bottom paint (my son-in-law was there in my stead). The rudder was painted. You never paint Stainless Steel!

I assumed it was strong fiberglass with a embedded SS rudder post. I am not sure now.

I removed the cover plate for access to the emergency tiller connection. I can see the top of a metal stud.

I put a galvanic test probe on that stud. I read -.02 millivolts reference to the Silver reference probe in sea water near the rudder. I was expecting to see Stainless (passive) to Silver millivolts of -50 millivolt. BTW by doing this galvanic check, I can detect corrosion in advance and not have to pull and look.

If my guess is right, Hunter used Alloy 20 Stainless. That would be ≈zero mV. That is why I hoped to find a detailed plan or knowledge here at SBO.

They used that "no sea water crevice corrosion" grade of stainless steel, I hope.

OR...

The rudder post is NOT in electrical contact with the sea water (great for lightening protection to Helmsman), meaning fully encased in fiberglass.

I did notice that the metal emergency tiller was electrically isolated from the rudder post (good thinking/design).

Thanks for the feed back.
Jim...