What is parallel indexing on radar and what is it used for?

A. A technique for measuring the distance between two vessels on the radar screen

B. A method of aligning two radar targets to fix position

C. A technique where the navigator sets a line parallel to the intended track at a predetermined distance from a radar-conspicuous object — as the vessel moves, a return should track along this line confirming the vessel is maintaining the correct track clear of dangers

D. Parallel indexing is only possible with ARPA radar — standard radar cannot perform it

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