We sailed a Soling for about 20 years and found that the iron keel did take some attention. Periodically we''d get blisters in the epoxy fairing to pop and refill, and fairing to work on if we hit something hard underwater. The keel/hull joint needed similar work as for any keelboat. We drysailed the boat about a third of the time (six-seven seasons). We''ve had to perform similar work on our lead-keeled boat.
One thing that scared me about iron keels, however, was seeing one which, when hauled out had globlules of iron filings clinging like leeches all over one side of it. When you touched them, it broke the surface tension of the moist outer layer, and the powdery filings fell to the ground. Apparently the boat was docked in a marina near a boat notorious for electrical problems. The stray electrical currents from the neighbor were strong enough to draw the iron out through the paint (which appeared unblemished). I don''t know how long it might have taken, but the keel would eventually have turned into swiss cheese.