Sailing and power-driven vessels

A photograph of a mast does not determine whether a vessel is legally sailing. Rule 3(c) requires being under sail without using propelling machinery. A sailboat using mechanical propulsion is power-driven in that state. The distinction affects encounters and signals, not merely its commercial model category. The first panel separates states of the same fictional hull; the second explains the wind relationship used by Rule 12 without depicting a manoeuvre. A boat’s design does not fix the legal state in which it operates at every moment.

Rule 12 lies in Section II, applicable to vessels in sight. Paragraph (a) concerns two sailing vessels approaching with collision risk. Section I remains relevant, and Rule 13 overtaking may be decisive. “Both have sails” therefore does not finish the assessment. Retain actual classification, visual condition, risk and overtaking relationship. Additional Rules 9 and 10 obligations in channels and traffic schemes also remain. A diagram that omits those conditions can help explain wind geometry but cannot independently determine all responsibilities in a real encounter.