My cast iron keel has no zincs. I am in the process of the first bottom job since I purchased this boat. When we did the haul out I discovered there were no zincs on the boat anywhere. I plan to add a shaft zinc and had planned drilling through the cast iron keel and placing a bolt through the keel with a zinc on each side. The marina that did the haul out did not recommend drilling and putting the zincs on the keel. They said the zinc on the shaft was enough. I had corrosion with some pitting on the keel, but nothing major. I would like to hear other opinions about the zincs in the keel. Any comments??? Thanks Jerry Smith Mobile Alabama