SAILING

Teaching Chart Details: A Navigator’s Checklist

On February 21, 2023
By Kimberly

Chart Details are important to a navigator. A basic understanding of these key items is crucial for the ability to read a chart. How many do you know? Which ones are unfamiliar to you?

I’m teaching a couple two-hour courses on charts this month, so I’m sharing with you my list of items to cover with my students. If there’s anything I forgot – please comment below. I strive to learn more, provide more, and better my own knowledge daily.

Chart Details

Title block
Datum and soundings
Scale
Symbols
Notes on sides
Latitude
Longitude
Equator
Zones of Convergence
Cardinal Directions
Prime Meridian Greenwich, England
Antimeridian IDL International Date Line zig zags.
Large scale = (detailed) small area, small scale = (broad) large area
Chart scale is the ratio of the distance on a chart to the distance on land or water.
A scale of 1:8 000 means that the chart is one eight-thousandths of the size of the area it represents: Objects shown as a centimeter apart are physically 8,000 centimeters (80 meters) apart.
A coastal chart usually has a scale of between 1:50 000 to 1:150 000.
The scale of a harbor chart is typically 1:10 000 or 1:20 000.
Hours minutes seconds
Degrees minutes decimals
In Geometry use X then Y – along the corridor, then up the stairs; here use opposite; state latitude (N/S) first, then longitude (E/W)
Notice to Mariners
Contour lines
Depth
Chart No. 1
True North, Magnetic North, Compass North, difference between them
Parallels of Latitude
Meridians of Longitude
Degrees North of Equator, South of Equator
Degrees East of Prime Meridian, West of Prime Meridian

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