Yachtmaster Ocean Theory Syllabus

This is a course in astro-navigation and worldwide meteorology which also reveals the mysteries of the sextant. It assumes a knowledge of all subjects covered in the other shorebased courses.1. The earth and the celestial sphere

  • Definition of observer’s zenith and position of a heavenly body in terms of latitude, longitude, GHA and declination
  • Right angle relationships, latitude and co-lat, declination and polar distance
  • Relationship between GHA, longitude and LHA
  • Tabulation of declination in nautical almanac
  • Rate of increase of hour angle with time

2. The PZX triangle

  • The tabulated components of the triangle, LHA, co-lat and polar distance
  • The calculable components, zenith distance and azimuth
  • Relationship between zenith distance and altitude
  • Introduction to the tabular method of solution in the Air Navigation Tables and the basic sight form
  • The use of calculators for the solution of the PZX triangle

3. The sextant

  • Practical guide to the use and care of a sextant at sea
  • Conversion of sextant altitude to true altitude
  • Application of dip, index error and refraction
  • Correction of side error, perpendicularity, index error and collimation error

4. Measurement of time

  • Definition of, and relationship between, UT, LMT, standard time and zone time
  • Rating of chronometers and watches

5. Meridian altitudes

  • Forecasting time of meridian altitude
  • Reduction of meridian altitude sights

6. Sun, star and other sights

  • Reduction and plotting of sun sights using
  • Air Navigation Tables
  • Awareness of use of calculator for sight reduction
  • The plotting of sun-run-sun meridian altitude
  • Awareness of the reduction and plotting of sights obtained from stars, moon and planets

7. Compass checking

  • Use of amplitude and azimuth tables systems and/or calculator

8. Satellite Navigation Systems

  • Principles and limitations of use of all systems

9. Great circle sailing

  • Comparison of rhumb lines and great circles
  • Vertices and composite tracks
  • The computation of a series of rhumb lines approximating to a great circle by use of gnomonic and Mercator projections

10. Meteorology

  • General pressure distribution and prevailing winds over the oceans of the world
  • Tropical revolving storms, seasonal occurrence and forecasting by observation

11. Passage planning

  • Publications available to assist with planning of long passages (routeing charts, ocean passages of the world and other publications)
  • Preparation for ocean passage including survival equipment, victualling, water and fuel management, chafe protection, spares and maintenance

12. Passage making

  • Navigational routine
  • Watchkeeping
  • Crew management

13. Communications

  • Satellite and terrestrial systems
  • Weather information

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