Article covered in blood brought on board by ship-builder mostly something to be avoided (2-2,4)
I believe the answer is:
no-go area
'something to be avoided' is the definition.
(area to be avoided)
I don't understand the rest of the clue.
(Other definitions for no-go area that I've seen before include "Zone where access is barred or risky" , "Barricaded part of a city in conflict" , "Out-of-bounds zone" , "It's taboo to enter" , "Region where entry is dangerous, impossible, or forbidden" .)