Rules of the Road
International/Inland
Lights & shapes
Rule 23-Power-driven vessels underway
(a) A power-driven vessel underway shall exhibit:
(i) a Masthead light forward;
(ii) a second masthead light abaft of and higher than the forward one; except that a vessel of less than 50 meters in length shall not be obliged to exhibit such a light but may do so;
(iii) sidelights; and
(iv) a stern light
*note on side lights. Red is port side (left) and green is starboard side (right)
Power-driven vessels less than 65.6 feet (20 meters) long must exhibit a red and green light on their starboard and port sides, respectively, when underway between sunset and sunrise in addition to an all-round white light. These lights help other vessels determine the direction of travel and avoid collisions.
Power-driven vessels less than 65.6 feet long must exhibit a green light on the starboard side and a red light on the port side, in addition to an all-around white light, when underway between sunset and sunrise. These lights help other vessels determine the direction the vessel is moving and avoid collisions at night.
Port and starboard steaming lights and stern light
Power-driven vessels less than 656 feet (20 meters) long must exhibit both a red light and a green light when underway between sunset and sunrise, in addition to the all-round white light. The red light should be on the vessel's port side, and the green light should be on the vessel's starboard side.
A masthead light, side lights and a stern light are the lights that power driven vessels less than 65.6 feet long and underway between sunset and sunrise exhibit.
In addition to an all-round white light, power-driven vessels less than 65.6 feet (20 meters) long must exhibit sidelights (red and green) and a sternlight when underway between sunset and sunrise. The red sidelights should be displayed on the port side, while the green sidelights are on the starboard side. These lights help indicate the vessel's direction and improve visibility to other vessels at night.
Rules of the RoadInternational/InlandLights & shapesRule 23-Power-driven vessels underway(a) A power-driven vessel underway shall exhibit:(i) a Masthead light forward;(ii) a second masthead light abaft of and higher than the forward one; except that a vessel of less than 50 meters in length shall not be obliged to exhibit such a light but may do so;(iii) sidelights; and(iv) a stern light*note on side lights. Red is port side (left) and green is starboard side (right)
Power-driven vessels less than 65.6 feet long must exhibit a white masthead light and a white stern light between sunset and sunrise when underway. Additionally, they should also display red and green sidelights when the visibility is restricted.
red and green sidelights
Port and starboard running light and stern light.
A sailing vessel under sail at night must exhibit red and green sidelights and an all-round white light when underway. The red light is displayed on the port side, and the green light on the starboard side, while the all-round white light indicates the vessel's presence and helps prevent collisions. This lighting configuration is essential for visibility and safety on the water.
A vessel that is underway but not making way would exhibit sidelights if it is a power-driven vessel or a sailing vessel with a motor. Sidelights consist of a green light on the starboard side and a red light on the port side, indicating the vessel's orientation. Even when not making way, the sidelights serve to signal the vessel's presence and direction to other vessels in the vicinity. Additionally, a vessel at anchor would display an all-round white light instead of sidelights.