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

A. 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

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

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 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