Anit-corrosive paints on the outside of ship's hulls fall into 3 groups: the area below the water, the boot- topping area at the waterline, and the weatherwork including the hull and superstructure. Typical formulations of primer and paint are given for use in each section. Anti-corrosion paints must always be considered in conjunction with the kind and amount of surface preparation that can be given. The requirement for faster descaling techniques and higher standards of surface preparation has led to the introduction of automated centrifugal abrasive blasting machines for all new plates and sections. If it is not possible to remove old coatings by abrasive blasting, then the traditional method of chipping followed by wire brushing must be used. The removal of mill scale by abrasive blasting can produce a clean metal surface which is liable to rapid corrosion unless it is painted immediately. A pre-fabrication or shop primer is used which is normally applied by airless spray equipment synchronized with the sand blasting machinery.