Jeremy Rogers designed 'em with a substantial shoe casting at the back edge of the keel with a pin on the bottom of the rudder.
I know it was original as after 40 years, ours had de-zinced and we phoned Jeremy for ideas. He said he'd seen one around his yard somewhere and after he'd looked it out and sorted out a price with us, we duly received a NOS 'factory fresh' casting, only needing the pivot hole bored and holes for the retaining pins through the keel. I belive it was probably the last spare one in the country so anyone else will need to get a pattern made and get one cast. Its not really a job you want a stainless fabrication for as if it got bent it could jam the rudder. I suppose it could be made that way, but I'd be concerned as well by crevice corrosion.
The pivot pin on the rudder protrudes enough and the pivot hole is high enough on the heel casting to amount to about 2" clearence for the bottom of the rudder from a level surface so unless you are daft enough to reverse into a (or dry out on) a rock its pretty well protected.
There are only two pintles in through bolted (with GRPed in nuts) gudgeons on the hull, one just above the prop and the other high up on the transom. The rudder itself is solid wood, probably teak.