Heres an idea. permanently mount the zinc to your dock, install the bonded stud in the cockpit as mentioned in a previous reply, then connect your boat to the dock mounted zinc via a cable you create with small clamps on either end, just the right lenght of course. Why go through this hassle and not just drop the guppie over the side? I've seen too many people forget the guppie is there and back out of the slip with it in place only to wreak havoc getting spun around one of the wheels. the guppies certainly arent as apparent as a bright yellow shore power cord or water hose, the're just a small diameter stranded cable with clear vinyl. Easy to overlook. just food for thought.