At a scale of 1:7,620,000 this chart covers the North Atlantic from Brazil to Newfoundland and Gibraltar to the Caribbean. It has been constructed on a conical projection that means that Great Circle tracks can be plotted as straight lines rather than curves.

Chart 100 shows the main trend of depth contours, limits of ice, magnetic variations and keys routes as identified by Donald M. Street Jr. In the enclosed booklet are pilot charts showing winds, currents and wave height frequencies with accompanying notes on favourable route timings and hurricane risk.

Chart 100 is an important companion for Atlantic yachtsmen on passage and an excellent source of planning information.