I have recently purchase a project hull. it is the double skinned dory type. I have just removed the old antifoul paint so I could get a better overall view of the hull condition, and I have found an area of about 300mm X 900mm where there are lots of hairline cracks going in all directions. Can anyone tell me how I identify the difference between cracks in the gel-coat and stress cracks in the hull. If they do turn out to be the latter do I have to cut this section out and replace it or can I just apply new gel-coat?