Hi Phill, There is an etching process during anodizing that can be pretty acurately controlled by experienced operators so that the mast wall thickness could be manipulated chemically to pretty close tolerances; sort of a chemical machining procedure to (relatively) easily and inexpensively remove material where you wanted to before the anodizing coating is applied. They used to do this on big boat masts, especially near the top, before carbon became a better option.



Also, I liked reading about the pleasure you get from casually working on your boat - exactly the way I feel about such activity. That's a good thing for a fleet owner! :-)



Take care, Mike