Yachtmaster Offshore Standard: Restricted-Visibility Command Board

The RYA describes a Yachtmaster Offshore as competent to skipper by day or night in a wide range of weather and assesses skippering, navigation, safety awareness and the collision regulations. Written revision can rehearse a defensible decision structure; it cannot demonstrate practical radar use, lookout, vessel handling, crew leadership or examination competence.

Open the command board by stating the legal and operational condition. Restricted visibility includes fog, mist, falling snow, heavy rainstorms and similar causes. When vessels are not in sight of one another in or near it, Rule 19 applies alongside Rules 4–10: lookout, safe speed, risk assessment, positive action and routeing duties remain active. There is no radar-only stand-on vessel and no automatic starboard-turn rule.

Keep own-ship control separate from target interpretation. Record speed and manoeuvring limits, engines ready for immediate manoeuvre, navigation lights, the correct Rule 35 signal, sight-and-hearing lookout and the next safe-water constraint. Safe speed is a continuous judgement, not a number chosen once when visibility first closes.

Audit the detection chain before trusting its output. Record radar range, tuning, rain or sea clutter, blind sectors, heading and speed inputs, motion or stabilisation mode and target-acquisition age. MCA guidance warns that incorrect heading or speed inputs can create serious ARPA errors and that a tracked solution can take up to about three minutes to settle. Keep AIS identity and ground-referenced data supplementary and do not use an uncertain VHF passing agreement to replace the Rules.

For every contact, record timed raw range and bearing observations, whether own course and speed changed, the maturity and input quality of any automatic vector, the applicable Rule 19 caution, the available sea room and the evidence that would show the action is working. There is no universal safe CPA or TCPA; the required margin depends on the complete circumstances.

Close the loop with a command brief: facts, uncertainty, immediate control action, helm and engine limits, crew roles, the next timed observation and the trigger for further action. If a fog signal is heard apparently forward and collision risk has not been determined not to exist, Rule 19 requires reducing to the minimum speed at which the vessel can be kept on course, taking all way off if necessary and navigating with extreme caution. Sound direction can be deceptive, so it is not a precise turn bearing.