I know you are frustrated right now but, hang in there. There are two schools of thought on this deal. One (where you seem to be right now) dump it at whatever you can get for it and cut your losses. Two (where I hope you get to) keep it, keep putting it back together better than it was when it broke and you will love your boat when it is finally done and you went through everything you did to get it there. There will be some controversy with this option. One of my good friends has been where you are and he went with the second option. He could not be happier about his boat and the way it performs now. His has been sunk, two blown engines, new interior, hull repair, complete rebuild of the deck and transem, just to mention SOME of the issues he had.
Keep in mind that as far as I know, noone ever gets what they think their boat is worth when they sell it and almost everyone at some point regrets getting rid of it even if they are getting a new one.
Just my 2 cents. Hope it all works out.
Jimmy