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.
CHART SCALES:
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.
Harbour Charts: are large scale, 1:5 000 -to- 1:15 000, and are used for
navigation in harbours or intricate, hazardous, shoal-infested waters.
Approach Charts: 1:15 001 -to- 1:50 000, are used for approaching coasts where a lot of detail is required.
Coastal Charts: 1:50 001 -to- 1:150 000, are used to show continuous extensive coverage with sufficient inshore detail to make landfall sightings easy.
General Charts: 1:150 001 -to- 1:500 000, give extensive
offshore coverage with sufficient inshore detail to make landfall sightings easy.
Sailing Charts: 1:500 001 and smaller, are used for
offshore navigation beyond sight of land.