Collision Regulations (COLREGs) and Lights, Shapes and Sound Signals
The steering and sailing rules
Learn the core rules by heart. Rule 5 - proper lookout by all means. Rule 6 - safe speed. Rule 7 - risk of collision; if in doubt, assume it exists. Rule 8 - action to avoid collision must be positive, made in ample time, and large enough to be readily apparent. Rule 13 - overtaking vessel keeps clear. Rule 14 - head-on: both alter to starboard. Rule 15 - crossing: the vessel with the other on her starboard side gives way. Rule 16 - give-way vessel takes early and substantial action. Rule 17 - stand-on vessel holds course and speed but may act if collision is imminent. Rule 18 - power gives way to sail, sail to fishing, fishing to vessels not under command or restricted in ability to manoeuvre.
Lights, shapes and sound signals
Know sidelights (red port, green starboard, 112.5° arcs), sternlight (white, 135°), masthead light (225° forward), and the all-round lights. Recognise the shapes: ball, cone (point down for fishing), cylinder (not under command / constrained by draught), diamond (towing). Sound signals in restricted visibility: one prolonged blast every two minutes for power-driven under way; two prolonged blasts with a gap for stopped; one prolonged plus two short for a vessel not under command, restricted in ability to manoeuvre, sailing, fishing or towing.
Traps
Questions often present a crossing situation where the give-way vessel is on your port side - you are stand-on. Do not forget that a vessel engaged in fishing does not include a vessel whose gear has been temporarily stopped. Remember that a vessel at anchor shows an all-round white light where best seen and, by day, a black ball forward.