I generally recommend that cruisers use Larger scale charts
for their greater accuracy, except for passage
planning, where Small scale "Sailing" charts are more convenient.
There are several scale levels of charts. A large-scale chart covers a small geographical area in greater detail, while a small-scale chart will cover a larger area in less detail.
Because large-scale charts show areas in greater detail, many features (that appear on a large-scale chart), do not show up at all on a small-scale chart of the same area.
The larger the figure indicating the proportion of the scale, the smaller the scale of the chart. A chart with a scale of 1:25,000 is on a much larger scale (and more detailed), for instance, than one whose scale is 1:4,500,000.
: are large scale, 1:5 000 -to- 1:15 000, and are used for navigation
in harbours or intricate, hazardous, shoal-infested waters.
: 1:15 001 -to- 1:50 000, are used for approaching coasts where a lot of detail is required.
: 1:50 001 -to- 1:150 000, are used to show continuous extensive coverage with sufficient inshore detail to make landfall sightings easy.
: 1:150 001 -to- 1:500 000, give extensive offshore
coverage with sufficient inshore detail to make landfall sightings easy.
: 1:500 001 and smaller, are used for offshore navigation
beyond sight of land.