SD - Think I found it...
your instructions on who to check for leaks, so I'll give those a try next spring. I did install a new radio/CD player this summer and it has a clock. It is wired directly to the battery bus bar with a fuse interlink. I don't recall the older radio having a clock. Maybe that is the cause for the increase current. The radio is grounded to common ground. The good news is that I don't see evidence of galvanic corrosion elsewhere on the boat, so even though the zincs are pretty much gone, they appear to be working.
Even new, the zincs are small, probably only a pound or so. When I bought the bought last year, the PO had installed two of these zincs and when I pulled it 3 1/2 months later, about 40 to 50% of them were gone, so since the boat sat in the water from May 1 to November 12 this year, the additional loss may be due to the almost 100% increase in-water time.
The waters that the boat is in is Salem Harbor, MA.