I have my doubts that one can rent a C-Dory in the San Juans per se. Orcas is out of the question. They only have a 16 foot open cockpit boat for rent at Deer Harbor. Lopez also is unlikely. The one possibility there is the Islands Marine Center (360.378.2688) but I have never seen a rental there. If they do have one, it likely is a SeaSport boat. Friday Harbor is the best bet, but I've only seen charters there. Call the Harbor at 360.468.3377 for info. Anacortes might have somthing, but a C-Dory I don't know. Try the chamber of commerce 360.293.7911. Hopefully someone else can chime in with better suggestions.