Alternative C - water

  1. Have a good working knowledge of charts, chart datum and symbols used.
  2. Display an aptitude in compass work by completing the following three activities:
    1. Read a mariner's compass marked in points and degrees and have knowledge of compasses generally.
    2. Know about variation and avoiding deviation. Be able to correct a magnetic compass course for variation and deviation to obtain a true bearing. Given a true bearing, successfully adjust this to obtain a compass course.
    3. Understand how compass error can be found from a transit bearing.
  3. Complete two of the following:
    1. Understand how a position may be found from two intersecting position lines.
    2. Understand what is meant by a 'cocked hat' position and how to use it safely. Plot a position from any three cross bearings
    3. Plot a position using the 'running fix' method.
    4. Plot a position using a combination of compass bearings and any one or more of the following:
      • satellite navigation system
      • vertical sextant angle
      • horizontal sextant angle
      • line of soundings
      • transits
  4. Be able to use tide tables and tidal stream atlases.
  5. Understand the use of the marine log to obtain distance run and speed.
  6. Understand the buoyage system for United Kingdom coastal waters and other methods of marking dangers and channels.
  7. Demonstrate your awareness of the latest developments in electronic technology such as the Global Positioning System and electronic charts.
  8. Undertake a coastal voyage of between four and six hours acting as navigator. A log should be kept showing courses steered, distance run, navigation marks passed and weather experienced. During the voyage:
    • Plot the estimated position every hour by keeping up the dead reckoning.
    • Whenever appropriate, and not less than once per hour, plot an observed position by bearings or other means of obtaining a fix.


The voyage should be planned on the chart beforehand using tidal streams to the best advantage and giving hourly courses to steer for an assumed speed.