Advice please annual anti foul stretched to 18 months International Ultra some cracking and peeling around waterline,but otherwise sound i wonder whether to prime these ares after scraping and feathering. which primer or just slap on antifoul
Any of the special purpose grey primers. Check on the tin of antifoul for the directions and use the same brands if it is convenient. I would remove all the loose paint and fair the surface with coarse wet and dry. The top photo shows too thick paint and it has started to crack. I would give the surface a hard water blast to shift all the flakey stuff. That looks like a timber hull. If it is just be cautious of the seams with the pressure washer. Cover the bare patches with several coats of grey primer.