Wow boats are expensive at the moment, that thing looks like it’s got a coat of under seal slapped on. God knows what the hull is like under it and how old is that engine?
I think it is antifouling on the hull and back of the tubes. The engine is 90s era I think based on the appearance - so def getting old. 4k is a lot for it I agree, but there isn't a lot out there at the moment