Nautical Charts
A nautical chart is the mariner's map of the sea. It shows depths, coastline shape, navigation marks, hazards, and other essential information. Charts are drawn to Mercator projection, with True North at the top and compass roses for measuring bearings.
Charts come in different scales: a small-scale chart covers a large area (e.g., an ocean passage chart) while a large-scale chart shows a small area in great detail (e.g., a harbour approach). Always use the largest scale chart available for the area you are navigating.
Key Points
- Charts show depths, coastline, marks, hazards
- Mercator projection — True North at top
- Small scale = large area (passage charts)
- Large scale = small area (harbour charts, most detail)
- Use the largest scale chart available for your area
Tip: Think of it like zooming in on a map: large scale = zoomed in (shows more detail). Small scale = zoomed out.