Module 7 of 17
Reading nautical charts, symbols, chart correction, and navigational publications.
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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, wi...
Charts use hundreds of standardised symbols defined in INT 1 (also known as Chart 5011 in the UK). Key categories include: depth contours and soundings, rocks and wrecks, buoys and beacon...
Charts must be kept up to date — new hazards, changed buoys, altered depths, and other changes are published in Notices to Mariners (NMs). Professional vessels correct charts weekly using...
Several publications supplement charts: the Nautical Almanac (e.g., Reeds or Macmillan's) contains tide tables, tidal stream atlases, port information, light lists, radio information, and...
Each chart has one or more compass roses printed on it. The outer ring shows True North (aligned with the chart grid). The inner ring shows Magnetic North, offset by the local variation....
The UK Hydrographic Office (UKHO) publishes a range of essential Admiralty publications, each identified by an NP number. NP5011 (the UK edition of INT1) is the definitive reference for a...
Keeping charts up to date is a legal requirement for commercial vessels and a matter of safety for all mariners. The primary mechanism for chart correction is the weekly edition of Admira...
Electronic charts come in two main types. Raster Navigational Charts (RNCs) are essentially scanned images of paper charts — they look identical to the paper version but cannot be interro...
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