Rules & lights
Recognise navigation lights and the key give-way rules.
Navigation lights
Masthead (white) + sidelights (red/green) + sternlight (white).
Sidelights + sternlight, but NO masthead light.
All-round red over all-round white. When making way, also sidelights + sternlight. Non-trawling fishing (shooting nets).
All-round green over all-round white — the only difference from other fishing (red over white). When making way, also sidelights + sternlight.
One all-round white light.
Red = port (left), green = starboard (right).
All-round green light over an all-round white light. E.g. cable or reaction ferry — no further lights.
Same green-over-white, plus sidelights and sternlight — but NO white masthead light.
Light sectors (angles)
Each light shines over a fixed angle. Together they make a full circle of 360°.
Key rules
- A masthead light is NOT all-round (225°). An all-round light covers 360°.
- The masthead light is always above the sidelights — never below.
- Vessels under 20 metres may combine the lights in one lantern; masthead and sternlight may be combined into one all-round white light.
- A sailing vessel NEVER carries a masthead light: only sidelights + sternlight. A small sailing vessel (< 20 m) may instead carry a tricolour lantern at the masthead (sidelights + sternlight combined).
- If a sailing vessel motors at night, it counts as a motor vessel: masthead light on. By day it then carries a cone, point down.
- A fishing vessel shows two all-round lights stacked: trawling = GREEN over white, other fishing = RED over white. When making way, the ordinary sidelights + sternlight are added. When lying still to shoot its nets it shows ONLY those two lights (no side/sternlights). While hauling in the catch it may show bright deck lighting.
- A ferry always shows an all-round green light over an all-round white light. A non-free-moving ferry (cable or reaction ferry) shows only that; a free-moving ferry also shows sidelights + sternlight, but NO masthead light.
- Remember for the exam: a ferry in service has right of way over ALL other vessels — not just small ones, but large vessels too. (In practice the ferry often waits for large ships.)
Light explorer: circle the vessel
Pick a vessel type and drag the observer around the boat. See live which lights become visible — linking the light sectors (112.5° · 135° · 225°) to what you actually see at night.
Masthead (225°) + sidelights (112.5° each) + sternlight (135°). Past the beam the sidelight disappears; from astern you see only the white sternlight.
Floating equipment
Floating equipment (dredger, pile driver, …) marks each side to show whether you may pass: green = free, red = not free. If both sides are free, it shows green on both.
Two green rhombuses (by day) or two green all-round lights (at night). You may pass on this side.
A red ball (by day) or a red all-round light (at night). You may NOT pass on this side.
Flashing lights
A flashing light draws extra attention. Its colour tells you who it is.
Police, fire service and enforcement officials (assistance / urgent duty).
A vessel carrying out works.
Give-way rules
Two motorboats head-on: both turn to starboard and pass port to port.
The vessel that has the other on its starboard side gives way. Here the blue boat gives way.
The overtaking vessel (blue) keeps clear; the overtaken vessel holds its course.
A small vessel must not hinder a large one and gives way with ample room.