Observe and identify
Developing level, about 3 min. IALA Region B.
The situation
You are following the northbound conventional direction of buoyage in Region B. Inspect the junction mark by playing its live light for a full cycle, then connect it to the chart plan.
Which branch does the mark prefer, and how do you leave it?
- Preferred branch to starboard; leave the mark to port
- Preferred branch to port; leave the mark to starboard
- A special mark giving no preferred branch
Answers and explanations
Lookout: Can and cylinder mean port; use Region B for the colour; the broad contrasting band identifies a channel division.
The sound answer
Preferred branch to starboard; leave the mark to port
In the direction of buoyage, leave this mark to port to follow the preferred branch. Reverse the passing side when travelling against that direction.
Why the other options fall short
Preferred branch to port; leave the mark to starboard
This mark retains the port-hand form and dominant colour for the selected region. It indicates the preferred channel to starboard.
A special mark giving no preferred branch
The broad contrasting band and composite (2+1) light identify a modified lateral mark, not a yellow special mark.
Modified lateral marks
At a channel division, the preferred branch lies to starboard when following the direction of buoyage. In the direction of buoyage, leave this mark to port to follow the preferred branch. Reverse the passing side when travelling against that direction.