RE: Touching up damaged powdercoating
This is the major drawback to powder-coating. I would call a powder-coating shop and ask them for their repair advice. I do know that it is very important to fix the crack, chip, or ding asap because if the metal underneath begins to corrode (aluminum) or rust (steel) this will spread fast and continue to lift more and more of the coating. I believe this is why powder coating is not usually recommended for items that are likely to get a lot of physical wear or abuse.
I'm sure there is at least one recommended repair procedure but I have no clue what it is. You could also try Googling the question, too.
If you find out, let us know since many of us have powder-coated items on our boats.