Navigation, Seamanship, Meteorology and Passage Planning
Core concepts
Navigation covers charts (datum, symbols, scale), latitude and longitude, compass work (true, magnetic, variation, deviation, deviation card), position fixing (GPS, bearings, transit, running fix, depth contours), dead reckoning and estimated position. Know speed, distance, time relationships, set and drift, and tidal height and stream calculations. Understand IALA buoyage (Region A lateral marks, cardinal marks, special marks, safe water marks), lights (characteristics, nominal range, sectors) and chart symbols for hazards.
Seamanship includes ropework (knots, bends, hitches, splicing), anchoring (scope, holding ground, swinging circle), mooring, towing, heavy weather handling and rules of the road basics (give-way, stand-on, overtaking, narrow channels).
Meteorology covers pressure systems, fronts, air masses, sea breeze, Beaufort scale, cloud types, fog formation and weather warnings. Passage planning follows a structured sequence: assess, plan, execute, monitor.
Traps in questions
- Applying variation the wrong way: variation east, magnetic least (from true to magnetic, subtract easterly variation).
- Confusing set (direction of tidal stream) with drift (speed).
- Using speed through water when ground speed is required over the ground.
- Misidentifying cardinal marks: remember the black/yellow pattern and topmark arrangement.
- Forgetting that deviation is vessel-specific while variation is geographic.
Rule of thumb: 60D = ST
Distance in nautical miles = speed in knots × time in hours. The factor 60 links minutes of arc to nautical miles.
Worked example: 8 kn for 45 minutes = 8 × 0.75 = 6 nm. If a current sets 2 kn on the beam for that period, drift = 1.5 nm; combine vectors to find course to steer.