Netted Day Signal Shapes

Day shapes are mast head signals visually indicating the status of a vessel to other vessels on navigable waters during daylight hours whether making-way, anchored, or aground. These signals consist of a set of simple geometric shapes—ball, cylinder, cone, and diamond—that are displayed, hung from a mast, in a prescribed manner to indicate a vessel’s operational status; some of these signals may be somewhat involved.

Day shapes are black in color and their sizes are determined by the ColRegs; for example, the size of the ball is not less than 0.6 metres (2.0 ft). The vertical distance between shapes is at least 1.5 metres (4.9 ft). Vessels of less than 20 metres (66 ft) length may use shapes of smaller size commensurate with the size of the vessel.