block. Replacing engine components like the alternator, starter and gaskets right down to the block is fine but I'll let a shop pull the engine to do anything with the pistons etc. I don't do refrigeration although I carry the vacuum pump and gauges and the "how to" book. It's just easer and probably cheaper the to let a professional do that as well. I'll replace radios, depth finders etc. but won't "fix" them. I'll do fiberglass repair and gel coat repair, plumbing, run wire, varnish and painting. I'll go up the mast and check rigging and replace it if necessary. I do my battery DC, AC systems and bonding system but when my stern tube failed I had the yard replace it with a new fiberglass one. I do a lot more work myself while out cruising then when the boats home although I have used some fine yards in Mexico, the BVI's and Puerto Rico. As I get older I'm slowing down a bit on the heavy lifting jobs like doing the bottom.