In 1970 a review of the Sailing Directions was undertaken to find out if they met the needs of the twentieth-century mariner. This review was based mainly on the response to a questionnaire promulgated by Notices to Mariners, to which some 900 replies were received. The general assessment was that considerable improvement was required in the port and pilotage information; a loose-leaf type of book, for ease in correction, was also suggested.

The outcome of the review was the adoption of a new style, involving a stricter geographic sequence in dealing with the coastal features, more headings to divide up the text and proper names highlighted by the use of bold type at the principal mention. At the same time the international A4 size was adopted to provide a shorter line of print in two columns, and a better page size for graphics. Much pure description of the chart has been removed, but there is still rather too much repetition of detail which can already be seen from the chart.