Advanced Scenario Check: Terms

Scenario: the transit expected before the turn has not closed, depth is reducing faster than planned and GNSS shows the yacht offset from the EP. The crew report the correct lights, but visibility is worsening and the tidal-gate margin is narrowing.

Do not average contradictory evidence into false confidence. First decide which observations share a common source: a chartplotter position, ground track and derived cross-track error may all depend on the same GNSS input. A visual transit and depth can be more independent, but both still require correct identification, chart datum, position and interpretation.

The first command is the action that preserves options—slow, stop where safe, turn away or create sea room according to the vessel and pilotage plan. Then allocate the recheck: one person verifies objects and bearing, another confirms depth and position, while the helm follows one clearly referenced instruction.

State the abandonment trigger before continuing. If the required independent evidence cannot be established, the clearing limit is approached, visibility falls below the plan or the gate is missed, use the safer alternative. A decision table helps revision; it is not a substitute for local pilotage, vessel handling or the skipper's real-time judgement.