Regions A and B: state buoyage direction first

A lateral mark identifies a side of a channel. Understanding it needs two references: the IALA region and the conventional direction of buoyage.

That direction is established for the place; it does not follow each boat’s bow. This explains why the same mark can appear on our left on one journey and on our right on the return, without changing its identity.

The diagram’s arrow fixes the conventional direction. Imagine looking along it: port is to the left and starboard to the right.

Those sides classify the marks in that direction, rather than the viewpoint of someone ashore or taking a photograph from an opposite heading. Chart north is a different reference: a buoyage arrow can point north, south or in any other direction.

Lateral colours change, including the light when fitted. The sides associated with shapes remain: can for port, cone apex upwards for starboard.

A can has a flat top; a cone ends at an apex. Not all buoys have these distinctive bodies.

A pillar or spar can carry the corresponding topmark where practicable. This upper recognition feature helps identify the mark; it is not a radar reflector.

The regional change does not swap cardinal, isolated danger, safe water, special or emergency characteristics. A north cardinal remains black above yellow with two upward cones in both regions.

Europe uses Region A, including Portugal and the United Kingdom. Region B includes the Americas, Japan, the Republic of Korea and the Philippines, among other areas.

The reference for a particular area should be confirmed in the appropriate nautical documents.

R1001 provides for the general direction of approach from seaward to a harbour, river, estuary or other waterway. It also allows a direction determined by the competent authority, consulting neighbouring countries where appropriate; in principle it runs clockwise around landmasses.

“Entering, red to port” is a memory aid for A, but does not replace the definition. A through-channel may need a published reference that cannot be inferred simply from the word entering.

Portaria 177/2016 adopts Region A and assigns technical direction to Direção de Faróis within DGAM. It commenced on publication on 24 June 2016 and transposes IALA’s 2010 revision.

The international recommendation consulted here is June 2023. A newer recommendation does not automatically amend the national act.

R1001 and RBMN also relate numbering and lettering to conventional direction; even numbers on red and odd on green should not be extended to every aid type or used instead of local identification.

A boat’s port and starboard are fixed sides, defined when looking forward from stern to bow. They do not change when someone turns around.

Lateral marks apply those same names to a channel with its declared conventional reference. Keeping the two uses separate also avoids confusing a red buoy light with a vessel’s red navigation light, which belongs to COLREGs and serves a different purpose.