[C320-list] Rudder post deck plate

[Scott Thompson]

I've been aware for some time that the deck plate for the emergency 
tiller on Surprise is leaking.  Indeed this is the only source of 
possible fresh water in the bilge that I could identify, when I found 
the bilge full of fresh water recently.  I cannot find any mark of a 
manufacturer on the plate.  Does anyone know a source for the gaskets on 
these somewhat unusual deck plates.

Surprise is a 1999 vintage boat.