What lights must sailboats show when underway at night?

What lights must sailboats show when underway at night?

• A. A towing light above the stern light
• B. Red and green sidelights and a stern light
• C. Identity lights at all times
• D. One all-round white light

Answer: (B)

When a sailing vessel is underway at night, it must show red and green sidelights plus a white stern light. The red sidelight marks the port (left) side and the green sidelight marks the starboard (right) side, telling other vessels where you’re coming from and which way you’re heading. The white stern light behind you helps others judge your position and angle from behind. The other options don’t fit the underway-at-night requirement: a towing light is only used if you’re towing; identity lights are for specific regulatory situations; and a single all-round white light alone doesn’t convey your direction while underway.

When a sailing vessel is underway at night, it must show red and green sidelights plus a white stern light. The red sidelight marks the port (left) side and the green sidelight marks the starboard (right) side, telling other vessels where you’re coming from and which way you’re heading. The white stern light behind you helps others judge your position and angle from behind. The other options don’t fit the underway-at-night requirement: a towing light is only used if you’re towing; identity lights are for specific regulatory situations; and a single all-round white light alone doesn’t convey your direction while underway.