Module 5 - COLREGs
Day Shapes
Day shapes are black shapes hoisted where they can best be seen during daylight to indicate a vessel's status or activity. They supplement or replace lights during the day and are required by Part C of the COLREGs.
A vessel at anchor displays a ball. A vessel motor-sailing (under sail and engine) displays a cone with the apex pointing downward. A vessel not under command (NUC) displays two balls in a vertical line. A vessel restricted in ability to manoeuvre (RAM) displays ball-diamond-ball in a vertical line.
A vessel constrained by her draught (CBD) displays a cylinder. A vessel towing, where the tow exceeds 200m, displays a diamond shape (both towing vessel and tow). A vessel engaged in fishing with gear extending more than 150m horizontally displays two cones with their apexes together (point-to-point) in the direction of the gear.
Key points
- Ball — vessel at anchor
- Cone apex down — motor-sailing (engine + sails)
- Two balls — Not Under Command (NUC)
- Ball-diamond-ball — Restricted in Ability to Manoeuvre (RAM)
- Cylinder — Constrained by Draught (CBD)
- Diamond — towing with tow exceeding 200m
- Two cones apex together — fishing with gear extending >150m
Tip: Day shapes must be displayed where they can best be seen. On a yacht motor-sailing, the cone should be hoisted forward — though vessels under 12m are exempt from this requirement.
Continue studying COLREGs
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