Yachtsmen, like other mariners, are being encouraged to ‘think metric’—to become accustomed to metres in Tide Tables, Pilots and Light Lists, and to make use of the new metric charts as and when these become available. Along with these changes to books and publications we can expect the introduction of metric tide gauges, and of echo sounders calibrated not in feet or fathoms but in metres. In a few years time even those yachtsmen who normally never correct their charts, or who do not think about renewing them until they are covered with cocoa stains, will be forced to work in metres.