Day shapes
Day Shapes are mast head signals indicating the navgation status of a vessel at sea to other vessels.
The meanings of the shapes are defined by the International Regulations for Preventing Collisions at Sea.
The most common signals are as follows:-
| Navigation status | Day shape | Restriction |
|---|---|---|
| Vessel Under Sail & Power | Cone | > 12m |
| Anchored | Ball | > 7m (not in channel) > 20m (in anchorage) |
| Constrained by Draft | Cylinder | |
| Aground | 3 Balls (vert. line) | > 12m |
| Not Under Command | 2 Balls (vert. line) | > 12m |
| Restricted in Ability | 1 Ball+1 Diamond+1 Ball | > 12m (except dive boats) |
| Fishing (commercial) | 2 Cones (vert. line) | > 20m (but must display (nets or trawling) basket shape |
| Vessel Towing | Diamond | Tow > 200m |
| Vessel Being Towed | Diamond | Tow > 200m |