Salt vs. Fresh water
You're in Florida, and the answers posted (except LaDonna) are fresh water people. BIG DIFFERENCE. I own a '74 C27 with a non-anodized mast that spent the 1st 10 years of it's life in SF Bay salt water. Warm Florida water corrodes faster than cold SF Bay. The white powder-type stuff you see on the face of the aluminum is a form of corrosion that offers a somewhat protective coating to the underlying aluminum. Not harmful if left alone. Problem is if you sand or scrape the white powder off, now the bare aluminum is back to the salt air, and the corrosion starts again. Either leave it alone (if not too bad), or do what I did and drop the mast and paint with LPU after sanding ALL the corrosion off. (and I mean ALL, the slightest little bit left on will be like cancer and start it again, but this time bubbling underneath your nice LPU!) See May '94 mainsheet under the C27 tech area for the whole story... I'm surprised such a late C30 has an un-anodized mast. Catalina began anodizing some time in the mid-70s. Has the mast been replaced? If it is an older mast, you may need to drop it anyway to replace wood spreaders. Good luck!
