Final answer:
A vessel over 50m must display specific lights and day shapes to indicate its size and type. The lights include a white masthead light, a stern light, and a red light on the port side. Day shapes include a ball shape for anchoring and two black balls or black cones for restricted maneuverability or sailing.
Step-by-step explanation:
For a vessel over 50m, there are specific lights and day shapes that must be displayed to indicate its size and type. These lights and day shapes help other vessels determine the size and maneuverability of the vessel and take appropriate action to avoid collisions.
Lights:
A vessel over 50m must display a white masthead light at the front of the vessel, a stern light at the back of the vessel, and a red light on the port (left) side.
If the vessel is towing or pushing, it must display an additional yellow towing light.
A vessel at anchor must display an all-round white light.
Day Shapes:
A vessel over 50m must display a ball shape during the day to indicate it is at anchor.
If the vessel is restricted in its ability to maneuver, it must display two black balls vertically.
If the vessel is making way through the water using sails, it must display two black cones, apexes together, pointing upwards.