Re: C&C 27 Project Boat help!
You might try Mr Clean Magic Erasers for the scum line.. that stuff is pretty amazing. Failing that it might be wet-sanded and rewaxed if necessary.
The exposed compass and knotmeter are the least of your worries.. that's not unusual to see, btw.....
You'll have to rebuild the deck area around the hatches to accept the hinges again.. dig out the old/damp core and fill and fair with thickened epoxy.. there's no avoiding some paint or some way of hiding the repair though..
As far as the engine goes, you may have nothing more than an anchor there.. no point in trying to wedge the head off if there are still bolts holding it down, you'll just crack something. I think I'd be removing the thing whole and trying to work on it in a garage or shop somewhere... Assuming it's worth the effort, that is.
Does look like you've got yourself a bit of a project, alright!
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)