What is a tidal gate and how should a passage plan account for one?

A. A tidal gate is another term for a tidal stream atlas symbol on the chart

B. Tidal gates only apply to vessels over 20 metres in length

C. A point on the passage (headland, strait, harbour bar) that can only be safely transited within a specific tidal window — the departure time and speed must be calculated backwards from the tidal gate time to ensure arrival within the window

D. A lock gate at a tidal harbour — only relevant to inland waterways

A. The passage plan need only identify the destination — diversion decisions are made in real time

B. A port of refuge provides a safe haven if conditions deteriorate. Suitability factors: accessible in the expected conditions (depth, bar, height of tide); distance from passage track; available facilities (fuel, medical, communications); whether it can be entered at night; holding ground if anchoring is the only option

C. Any port on the chart is automatically suitable as a refuge regardless of conditions

D. Ports of refuge only matter for vessels without an engine — sailing yachts can always divert

A. Night passages are not permitted for vessels without radar — navigation is impossible

B. Only the watch system differs — all navigational aspects are identical at night

C. Night passages require no additional planning — use the same plan as daytime

D. Light identification (lighthouse characteristics, lit buoys); watch system and crew rest schedule; approach to destination in the dark (lights, leading lines, transit); traffic density in the area at night; vessel lighting check; crew experience of night sailing