A serious case of accelerated corrosion, resulting in deep pitting and perforations on the internal surface of a ship's bottom plate, was recently brought to our notice. During the relatively short period of less than 2 years, an 8 mm mild steel plate suffered three perforations of O·5 cm, 0·8 cm and 1·0 cm diameter. This necessitated dry docking and the renewal of a section of the ship's bottom plate.
