RYA Yachtmaster Ocean Theory

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 of time

The PZX Triangle

• The tabulation 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

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

Measure of time

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

• Rating of chronometers and watches

Meridian Altitudes

• Forecasting time of meridian altitude 

• Reduction of meridian altitude sights

Sun, Star and other sights

• Reduction and plotting of sun sights using

• Air Navigation Tables 

• Awareness of use of calculators 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

Compass Checking

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

Satellite Navigation Systems

• Principles and limitations of use of all systems

Great Circle Sailing

• Comparison of rhumb lines and great circles

• Vertices and compisite tracks 

• The computation of a series of rhumb lines approximating to a great circle by use of gnomonic and Mercator projections

Meteorology 

• General pressure distribution and prevailing winds over the oceans of the world

• Tropical revolving storms, seasonal occurrences and forecasting by observation

Passage Planning

• Publications available to assist with planning of long passages (routing 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 maintence

Passage Making

• Navigational Routine

• Watchkeeping

• Crew Management

Communications

• Satellite and terrestrial systems

• Weather information

To complete this course you must have competence in coastal navigation skills. 

RYA Coastal Skipper/Yachtmaster Shorebased Certificate is recommended