When you get some more time later in the day, would you mind telling me what you really think about this mechanic and don't hold back.
I totally agree with everything that you have said above. This mechanic is so clueless that he is just firing from the hip and saying stuff that he is hoping the OP just accepts as truth. I would run over and grab the boat and whatever else is yours from his shop and go find someone else because at this point in time, anybody else is better than this mechanic.