Final answer:
Power-driven vessels pushing ahead (composite unit) are required to display specific lights and shapes to indicate their status to other vessels.
Step-by-step explanation:
Power-driven vessels pushing ahead (composite unit) are required to display specific lights and shapes to indicate their status to other vessels. According to the International Regulations for Preventing Collisions at Sea (COLREGs), a power-driven vessel underway and pushing ahead is considered to be a vessel towing or pushing another vessel, and is required to display the same lights as a vessel towing, which are:
- A white all-round light at the stern.
- An additional flashing or steady yellow light on the side or sides of the composite unit being pushed.
In addition to these lights, the towing vessel must also display a basic set of navigation lights, including red and green sidelights and a white masthead light. These lights help other vessels determine the size, navigation direction, and status of the power-driven vessel underway.