True bearings, courses, latitude, longitude, and the knot.
True bearings and coursesStandard navigational termsLatitude and longitudeThe knot
3 outcomes for this module
Explain true bearings, courses, latitude, longitude, and the knot.
Apply True bearings and courses to a realistic onboard situation.
Recall the core check: latitude = N/S of Equator (0°–90°).
Preview the onboard scenario
You are preparing a real trip where your understanding of true bearings and courses shapes the decision. Use this module to explain the cue, the risk, and the next safe action before you move on.
You are preparing a real trip where your understanding of true bearings and courses shapes the decision. Use this module to explain the cue, the risk, and the next safe action before you move on.
On narrow screens, scroll sideways to reach every study mode.
Lesson summaries
Use this module hub to choose the right lesson, then open the dedicated lesson page for the complete explanation, worked examples, FAQs, and practice questions.
Latitude and Longitude
Position on the Earth's surface is defined using latitude and longitude. Latitude measures north or south of the Equator (0° to 90°N or S). Longitude measures east or west of the Prime Me...
A true bearing is measured clockwise from True North (0°/360°) through East (090°), South (180°), and West (270°). All chart work is done in true bearings initially — compass corrections...
True bearings: measured clockwise from True North
Always written as three figures (e.g., 005°, 090°, 180°)
Speed at sea is measured in knots — one knot equals one nautical mile per hour. Distance is measured in nautical miles (M or nm). One nautical mile = 1,852 metres = 1 minute of latitude.
1 knot = 1 nautical mile per hour
1 nautical mile = 1,852 metres = 1 minute of latitude
To measure a bearing on the chart, use a parallel ruler (or Breton plotter). Align the ruler along the line whose bearing you want to measure, then 'walk' it across to the nearest compass...
Use parallel rulers or plotters to transfer bearings
Read from the outer (True) ring of the compass rose
Distance on a nautical chart is measured with dividers and the latitude scale at the side of the chart. One minute of latitude equals one nautical mile, so the latitude scale is the only...
ALWAYS use the LATITUDE scale (side of chart) for distance
Worked DR example: at 1000 you fix your position. From 1000 to 1030 you steer 045 degrees true and the log shows 2.5 M through the water. Plot 2.5 M along 045 degrees true from the fix: t...
DR = course steered and distance through the water.
Keep reading the public lesson articles, and add this module's guided flow, quizzes, spaced-repetition flashcards, progress, and mock exams with one payment.