Sextant errors and their correction
- Introduction to the Grade 11 content
- 1 Navigation
- 1.1 Sailings
- Introduction
- Parallel sailing
- Plane sailing
- Mercator sailing
- 1.2 Astro navigation - geographical position and the nautical almanac
- The celestial sphere
- Declination
- Hour angle
- Geographical position
- 1.3 Rising and setting phenomenon
- Sunrise and sunset
- Twilight
- 1.4 The marine sextant
- Introduction
- Uses
- Parts of the sextant
- The sextant case and accessories
- Housing the sextant
- Reading the sextant
- Sextant errors and their correction
- 1.5 Altitude correction
- Introduction
- Observed to true altitude
- Sextant altitude
- Dip and apparent altitude
- Refraction
- Correction for sem-diameter
- Parallax
- Total correction
- 1.6 Determination of latitude at noon
- Introduction
- Time of meridian passage
- Finding the latitude
- Procedure to find the observer’s latitude
- 1.7 The tides
- The cause of tides
- Tide tables
- Definitions
- Use of the tide tables
- 1.8 Currents and tidal streams
- Nature of currents and tidal streams
- Definitions
- Plotting symbols
- Finding the set, rate and drift of a current
- Finding the estimated position allowing for a current
- Finding the course to steer to counteract a current
- Leeway
- 2 Seamanship
- 2.1 Cargo handling
- Cargo handling equipment
- Containers
- Cargo working gear
- Blocks and tackles
- Purchases and tackles
- Mechanical advantage
- 2.2 International regulations for the prevention of collision at sea
- General
- Steering and sailing rules
- Section I: Conduct of vessels in any condition of visibility
- Section II: Conduct of vessels in sight of one another
- Section III: Conduct of vessels in restricted visibility
- Lights and shapes
- Sound and light signals
- Distess signals
- 2.3 International Association of Lighthouse Authorities system of buoyage
- Introduction
- Buoyage regions
- Description of the system
- Lateral marks
- Cardinal marks
- Isolated danger marks
- Safe water marks
- Special marks
- New dangers
- 2.4 Safety at sea – emergency procedures and boat handling
- Stopping a vessel
- Methods of stopping a vessel
- Anchoring
- Search and rescue
- Rescue plans
- Rescue of persons falling overboard
- Boatwork in heavy weather
- Ship disabled or in distress
- Rescuing the crew of a vessel in distress
- Distress signals
- Abandoning ship
- Groundings, collisions and heavy weather damage
- Beaching
- Control of fire at sea
- Towing
- 3 Meteorology
- 3.1 Meteorology for mariners
- Introduction
- Planetary wind circulation
- Oceanic winds
- Atmospheric pressure conditions
- Air masses and fronts
- Frontal depression
- Tropical storms
- Ocean currents
- 4 Communications
- 4.1 Distress and safety communications at sea
- General
- Distress frequencies and silence periods
- Distress messages (MAYDAY)
- Urgency message (PAN PAN)
- Safety message (SECURITE)
- Good radio procedures