Captain's License / Study Guides
🧭Navigation General
Navigation General tests your understanding of the tools and systems used for safe navigation. It's open book with a 70% passing score and covers aids to navigation, compass work, tides, weather, and electronics.
What's Covered
Aids to Navigation (ATON)
IALA-B system, lateral marks ('Red Right Returning'), buoy types (can, nun, pillar), ranges, ICW markers, special marks.
Navigation Publications
Nautical charts, Chart No. 1 symbols, chart scales, datum (MLLW), Coast Pilot, Tide Tables, Current Tables, Light List.
Compass
Variation (from chart compass rose), deviation (from deviation table), TVMDC formula (True Virgins Make Dull Company — Add Westerly), compass adjusting.
Tides & Currents
Tide types (diurnal, semi-diurnal, mixed), spring and neap tides, Rule of Twelfths (1-2-3-3-2-1), set and drift, current calculations.
Weather
Barometric pressure, Buys Ballot's Law, Beaufort Scale, fronts (cold, warm, occluded), cloud types, fog formation, hurricane avoidance, NOAA weather warnings.
Electronics
GPS, radar (interpreting contacts), depth sounder, VHF radio (Ch 16, 22A, 13), DSC/MMSI, AIS, EPIRB (406 MHz).
Study Tips
- 1.TVMDC: True Virgins Make Dull Company — CAE: Correcting (C→T) Add East; uncorrecting (T→C) add West
- 2.Red Right Returning: red buoys mark the right side of the channel when returning from sea
- 3.Rule of Twelfths for tides: in 6 hours the tide changes by 1/12, 2/12, 3/12, 3/12, 2/12, 1/12
- 4.VHF Channel 16 is the international distress and calling frequency — monitor at all times
- 5.Buys Ballot's Law: stand with back to wind, low pressure is to your left (Northern Hemisphere)
Common Mistakes
- ✗Applying TVMDC in the wrong direction — remember CAE (Correcting Add East) goes Compass→True
- ✗Confusing variation (changes with location, from chart) with deviation (changes with heading, from table)
- ✗Using the wrong compass rose ring — outer ring is True, inner ring is Magnetic
- ✗Forgetting that Rule of Twelfths gives the rate of change, not the absolute height
- ✗Mixing up lateral marks: red = even numbers = right when returning; green = odd = left when returning
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