It's The Law: Required Equipment

The masthead light and sternlight may be combined as an all-round white light on vessels less than 39.4 feet long.

The required navigation lights must be displayed between sunset and sunrise and during periods of restricted visibility.

Power-Driven Vessels Less Than 20 Meters Long When Underway

If less than 65.6 feet long, these vessels must exhibit the lights as shown in Figure 1. Remember, power-driven vessels include sailboats operating under engine power. The required lights are:

• Red and green sidelights visible from a distance of at least two miles away—or if less than 39.4 feet long, at least one mile away—on a dark, clear night.
• An all-round white light (if less than 39.4 feet long) or both a masthead light and a sternlight. These lights must be visible from a distance of at least two miles away on a dark, clear night. The all-round white light (or the masthead light) must be at least 3.3 feet higher than the sidelights.
  

An alternative to the sidelights and sternlight is a combination red, green, and white light, which must be exhibited near the top of the mast.

If less than 23.0 feet long, these vessels should:

• If practical, exhibit the same lights as required for unpowered vessels less than 65.6 feet in length.
• If not practical, have on hand at least one lantern or flashlight shining a white light as inFigure 3.