Day shapes
Day shapes are signals shown by day in all weathers on vessels to denote certain activities in which vessels are engaged.
In restricted visibility, the appropriate lights should also be displayed by day. You must be able to recognize these day shapes which are generally used by larger vessels.
Vessels at anchor
When at anchor, vessels greater than 7 m must display forward, where best seen, one black ball. This is not required for vessels of less than 7 m when at anchor, not in or near a narrow, fairway or anchorage, or where others normally navigate.
Vessels under power with sails set
A vessel proceeding under power with sails set, that is motor sailing, must display forward, where best seen, one black cone, point down.
Fishing vessels
A fishing vessel using trawls, nets or other gear, whether under way or at anchor must display in a vertical line, two black cones pointing toward each other.
Vessels not under command
No day shapes are required for vessels under 12 m, except those engaged in diving operations. Vessels greater than 12 m, must display two black balls in a vertical line where they are best seen. This indicates inability to manoeuvre not distress.
Vessels constrained by their draught
A power-driven vessel restricted to a narrow channel by her draught and thus unable to deviate from her course must display one cylinder where it is best seen.
Vessels aground
A vessel greater than 12 m aground must display three black balls in a vertical line where they are best seen. This signal does not indicate distress or a need for help and is not required for vessels under 12 m length.
Vessels restricted in ability to manoeuvre
A vessel restricted in its ability to manoeuvre, for example, one engaged in flying aircraft, laying cable laying, replenishment at sea, underwater operations, servicing navigation marks, towing, where manoeuvre is restricted by tow, must display a black ball, black diamond, black ball in a vertical line where best seen. This signal does not indicate distress or a need for help. When at anchor, the vessel must also show the shape required at anchor.
Vessels engaged in underwater operations or dredging
A vessel with an obstruction on one side because they are engaged in underwater operations or dredging shall display two black balls on the side of the obstruction, and two black diamonds on the side on which vessels may pass. The ball, diamond, ball shape that indicates a vessel is restricted in its ability to manoeuvre must also be shown.
Black balls on both sides may be used to indicate passage or channel is blocked and vessels should await instructions before proceeding.
Power-driven vessels towing
A power-driven vessel towing another when the length of tow is greater than 200 m must show one black diamond where best seen. The same shape must also be displayed on the towed vessel.
