Well do I remember, about 20 years ago, when my Dad's Mariner 47 was at a well-known "marine railway" (hint, hint) on the upper Cape (Cod). Her toe rail had been damaged in a blow, and one of the a/c systems wouldn't cool. I had to show the yard refrigeration "mechanic" how to leak-detect a water-cooled condenser, as he hadn't a clue (at about $85/hour-in 1989). Later, someone was getting aboard from a dinghy while I had the generator running; he grabbed a stanchion and was knocked back into the dinghy by 115 Volts a.c., which I confirmed by connecting a voltmeter to the stanchion. After nearly a week of tearing things apart below, I discovered that the yard people, when replacing the stanchion on the new toe rail, ran a long wood screw through the deck and straight into a cable bundle. (Originally the stanchion had been, properly, through-bolted with a backing plate-only a lazy idiot would use a wood screw). I own an 18' Marshall cat, on which I do all of the work. I will only buy a larger boat (hopefully to live aboard) when I'm sure I'm in a position to do all of the work on that, as well. I will NEVER trust a yard to do anything more than perhaps remove and apply bottom paint.