Collision Regulations and Buoyage
Core concepts
You must know the steering and sailing rules (COLREGs) cold: the give-way and stand-on vessel roles, the requirement to keep a proper lookout and a safe speed, and the specific rules for head-on (both alter to starboard), crossing (give-way vessel alters to starboard and passes astern), and overtaking (overtaking vessel keeps clear). Learn the hierarchy of responsibility: vessels not under command, restricted in ability to manoeuvre, constrained by draft, fishing, sailing, and power-driven vessels. Understand IALA Region A buoyage (South Africa uses Region A): port-hand red can, starboard-hand green cone, safe water, isolated danger, special marks, and cardinal marks with their topmarks and light rhythms.
Traps
The classic trap is the crossing rule: the vessel with the other on her starboard side is the give-way vessel. Also watch the difference between 'in sight of one another' and 'restricted visibility' rules. Cardinal mark questions often test the topmark and light characteristic, not just the colour. Remember that a vessel engaged in fishing has right of way over a sailing vessel in many cases.
Worked example
You are under power, steering 000°. Another power vessel is sighted bearing 045° (on your starboard bow), steady bearing and closing. You are the give-way vessel - alter to starboard and pass astern of her. If the bearing were 315° (port side), you would be stand-on and should hold course and speed.
Rule of thumb
'If she's on your starboard side, you give way.' For cards: North = two cones point-up, South = two cones point-down, East = cones base-to-base, West = cones point-to-point.