What is a clearing line and how does it differ from a leading line?

A. Clearing lines only apply in harbours, not in open coastal waters

B. A clearing line defines the boundary of a safe area — when two charted objects are in transit, the vessel is on the edge of safe water. The navigator maintains position on one side of the transit (e.g. "keep the church in line with the cliffs or to the south") to stay clear of a danger

C. A clearing line is a safety depth contour drawn on the chart plotter

D. Clearing lines are the same as leading lines — both guide vessels through a channel

A. The almanac page for the port read below decks as you approach

B. A pilotage plan is only required for commercial vessels entering commercial ports

C. Large-scale chart of the harbour; tidal height at entry time; leading lines and transit bearings; light characteristics of key marks; VHF channel for port/marina; depth of bar or shallowest point; hazards on approach; abort decision point; a sketch on a card visible at the helm

D. Only the GPS waypoints for the harbour entrance — GPS provides all other information

A. Leading lines are depth contours marked on the chart to guide vessels along the 5m contour

B. Leading lines require a radar to use — they cannot be identified visually

C. Only day marks can serve as leading lines — lit structures cannot be used at night

D. Two charted marks aligned in transit indicate the centre line of the safe channel. Keep both marks in line (one above the other) to maintain the correct track. If the marks separate, steer to bring them back in line. The bearing of the transit is fixed and compass-error-free