
The original Mk1 Bronze rudder post fitting
Best bet would be to make a wooden pattern of the rudder post fitting and take it to a foundry and have them cast one for you.
I don't think Swarbricks are really that interested in the old boats.
Swarbricks didn't have the fitting that Andy required although they had a pattern for one. They did however have a couple of the updated spade rudder versions of these so I took one of the newer versions. Unfortunately the square tapered hole that fits the rudder post is different in the later versions. The angle of the taper for the old mk 1 rudder is 7 deg and the new one is 10 deg,,, so I had to re cut the angle in the block to 7 deg to suit Andy's rudder,, and it's not the simplest of things to set up for.

Squaring up casting

Taper re cut to 7 deg to suit MK1 post

Stainless steel Tiller hinge made to suit
I had a similar problem with a brand new Mk1 rudder.. The rudder I was supplied had the 10 deg latter version taper cut on it instead of the 7 deg (which they were given as a sample) so it wouldn"t fit the tiller hardware. I had to re cut the taper on the brand new rudder post.

The whole rudder needed to be set up and supported and indexed four times.