The lower gudgeon fitting developed some metal fatigue cracking in the 1.6mm stainless plate strap, it's likely to be over 30 years old. It's a critical fitting its failure would mean loosing the rudder and steering.
The gudgeon fittings straps were glassed into the stock, removing them would require some major angle grinder surgery..
So took the rudder to an engineering shop who could repair the existing fitting with TIG welding (less heat to burn the fibreglass) they also added a 3mm stainless plate to span the front of the stock and it was welded to the existing side straps which protrude from the fibreglass gel coat..
The engineer commented that the fittings looked a bit too light weight for the size of the rudder and boat. So next time it starts cracking up the plan is the beef up gudgeon and pintles with thicker steel.