Meteorology & Passage Planning Flashcards

A CPA (Closest Point of Approach) calculation shows another vessel will pass 0.1 nm off your bow in 8 minutes. What is the most appropriate action?

Answer: Take early and substantial avoiding action well before the CPA, as 0.1 nm is too close

0.1 nm is dangerously close — at most small craft speeds this is under a minute of travel. The give-way vessel must take early, substantial action (COLREGs Rule 16) well before the CPA.

A passage plan for a coastal trip should include which of the following?

Answer: Intended route with waypoints, hazards, tidal gates, weather windows, abort points, and emergency contacts

A proper passage plan covers: route, waypoints, depths, tidal gates (timing critical for headlands), weather window, potential anchorages, abort options, and who holds a float plan ashore.

A 'tidal gate' in passage planning refers to:

Answer: A point where the tidal stream becomes favourable or adverse at a specific time, making timing critical

A tidal gate is a stretch of water or headland where the tidal stream has a decisive effect on passage speed, safety, or feasibility. Timing arrival at tidal gates is a key passage planning skill.

What does 'leeway' mean for a sailing yacht?

Answer: The sideways drift of a sailing vessel caused by wind pushing the hull to leeward

Leeway is the angular difference between the direction the boat is pointing (heading) and the direction it is actually moving through the water (course made good through water), caused by the wind's sideways force.

A vessel's GPS shows Course Over Ground (COG) as 080°T and speed 5 knots. The compass heading is 090°T. What is the tidal set?

Answer: The tide is setting toward approximately 350°–010°T (pushing northward), shifting the track left

The COG (080°) is to the left (north) of the heading (090°). This means the tide is pushing the vessel northward (set approximately north). The helmsman must steer right (090°) to track toward 080°.

What information does a Navtex message provide?

Answer: Navigational warnings, weather forecasts, and urgent notices to mariners for coastal waters

Navtex (NBDP radio) automatically broadcasts navigational warnings, meteorological forecasts, and search-and-rescue information on 518 kHz in English for coastal waters.