If the mooring is paid until end of May, is there a way to extend it to June? It is only a few (overnight sail/motor) to Portland, ME so it doesn't cost you much in time.
The other option is to call the Harbormaster in Salem or Marblehead, MA and asked if they have a vacant mooring that they can put you on for little or no money for a few weeks. Explain that you just bought a boat, have a place for it until May but need a few more weeks at another location until June before you can move her. They are pretty accommodating if they have space.
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