Dear Mr. Lange or Lange-san:
I performed the rudder repair work myself except for the welding component and can say that the repair is very straight forward and can be done in about 5-7 days time.
To properly weld the strap bushings to the rudder stock the entire rudder assembly should be removed from the boat.
Removal of the rudder assembly goes quite quickly. First remove the rudder quadrant and loosen the rudder stuffing box. Next grind away the fiberglass fairing at the bottom tip of the skeg to expose the cast bronze shoe which supports the bottom of the rudder stock.
Remove the 4-5 bolts securing the bronze shoe to the fiberglass skeg. You may need to heat up this shoe with a hand held torch to release any epoxy used to secure the bronze shoe to the skeg. Be very gentle here not to heat distort or hammer distort this shoe since this is a custom Swan casting and not overly robust.
Once the bronze shoe has been freed the entire rudder assembly should slip out. Have a helper here since my rudder assembly weighed about 90 pounds.
Once the rudder assembly is off the boat remove the stainless steel shrouds covering the stainless steel rudder stock along the leading edge of the rudder blade. Next grind away the fiberglass fairing to expose the stainless steel straps holding the fiberglass rudder blade. Remove the stainless steel bolts from the strapping and the fiberglass rudder blade should separate from the strapping.
Clean the stainless steel rudder stock, strapping, etc with a wire brush wheel on a grinder. You will probably see numerous areas of crevice corrosion and pitting. The factory rudder stock is 40mm and I concluded that this is a very conservative design and unless I saw an obvious area of concern the shaft, although not pretty, was structurally OK for another 37 years. Also one should keep in mind that unlike contemporary spade rudder designs the older Swans have skeg hung rudders where the bottom of the rudder stock is supported by a bottom shoe and at the top so dynamic loads are supported at two locations.
I had my local rigging shop perform a TIG weld to continuously weld the top and bottom faces of both the upper and lower strap bushings. The welds were then ground smooth. Before you have the bushings welded double check their alignment and location with the rudder blade. I had to re-weld one of my bushings due to a slight mis-alignment.
Passivating would not hurt but I did not have enough time so I did not do this.
Re-assembly is reverse of dis-assembly. Make sure to replace all stainless steel bolts with new. Per Swan factory technical director?s direction all bolts should be torqued into place using a wrench on a double nut arrangement. Using a screw driver is totally inadequate.
I also replaced the bushing/bearing in the cast bronze shoe with a composite unit from this web-site http://www.garlockbearings.com. Again per Swan factory technical director?s comments do not use Teflon since this will expand when in contact with water and may cause binding and also not to use any graphite type material against stainless steel as this may promote crevice corrosion.
The time consuming component for me was the re-fairing of the rudder blade at the straps, shrouding of the rudder stock and the cast bronze shoe. I am pretty finicky about these and it took multiple applications over a course of 3-4 days to achieve satisfactory results.
I have attached photos for your info.
Happy to answer any questions. Hiro