A yacht has 4 crew on a 36-hour offshore passage. What watch system balances effective watchkeeping with adequate crew rest?

A. One crew member on watch at all times with the others available if needed

B. All 4 crew on watch simultaneously for maximum safety, sleeping in shifts of 2h

C. Watches only required when crossing shipping lanes — otherwise no formal watch needed

D. Swedish watch (common on yachts): 6h on / 6h off for 2 pairs, or 4h watches with 4 crew. Each crew should get minimum 6h sleep in any 24h. The skipper should plan for reduced cognitive ability in all crew after 20h without sleep

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. 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

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

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

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