Who gives way

Everything in the collision regulations hangs off two rules that have no exceptions, no priorities and no excuses — the lookout and the assessment of risk. They are short enough to know verbatim:

Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision.

Every vessel shall use all available means appropriate to the prevailing circumstances and conditions to determine if risk of collision exists. If there is any doubt such risk shall be deemed to exist.

The practical risk test is a steady bearingsteady bearingA converging vessel whose bearing does not change while range closes — you are going to meet.full glossary →: watch a converging vessel over the rail or with the hand-bearing compass — if her bearing does not change and the range closes, you are going to meet. Note the rules’ humility: any doubt means risk exists. You never argue yourself out of taking action.

Between two power-driven vessels: meeting head-on, each alters to starboard and passes port-to-port. Crossing, the vessel which has the other on her starboard side gives way — and the rules ask the give-way vesselgive-way vesselThe vessel required to keep out of the way — early, boldly and visibly.full glossary → to act early, boldly and visibly, ideally avoiding a turn to port for a vessel on her own port side. The stand-on vesselstand-on vesselThe vessel that holds course and speed — until it is clear the other is not acting.full glossary → holds course and speed — until it becomes clear the other is not acting, at which point she too must manoeuvre.

Between two sailing vessels: different tacks, port tack gives way; same tack, windward gives way. (Port tack here means wind on the port side.) And one rule trumps the lot regardless of sail or power: an overtaking vessel — anything approaching from more than 22.5° abaft the beam — keeps clear of the vessel being overtaken, for as long as it takes.

Sail does not outrank everything. A yacht under sail gives way to vessels not under command, restricted in their ability to manoeuvre, constrained by their draught, and to vessels engaged in fishing — and motor-sailingmotor-sailingSails up with the engine driving — legally a power vessel, cone point-down by day.full glossary → (sails up, engine driving) makes you a power vessel, with day shapeday shapesThe black balls, cones, diamonds and cylinders vessels hoist by day to declare their status.full glossary → to match. In narrow channels, small craft under 20 m and sailing vessels do not impede vessels that can only navigate inside the channel: practically, a yacht keeps to the edge and crosses fast at right angles, never dawdles down the middle.

Traffic separation schemes

Where shipping concentrates — the Dover Strait is the famous one — traffic is organised into separation schemes: one-way lanes divided by a separation zone, all printed in magenta on the chart. Rule 10 sets the small-craft etiquette. Join or leave at the ends where you can; if you must CROSS, do it on a HEADING as near as practicable at right angles to the lane — heading, not ground trackground trackThe path actually made over the seabed, tide included.full glossary →, so that even with tide skewing your path, approaching ships see your full beam and read your intent instantly. Cross briskly, don’t anchor in a scheme, and stay out of the separation zone except to cross it.

And the rule that surprises sailors: inside a scheme, vessels under 20 m and sailing vessels shall NOT impede power-driven vessels following a lane. Your sail rig buys no priority here. Where an inshore traffic zone exists, small craft are generally expected to use it rather than the lanes — usually the more pleasant water anyway.