Boat Navigation Lights & Day Shapes

Enhance on-water safety by learning the meaning behind navigation lights for boats and day shape configurations to avoid a collision on the water.

Boat navigation lights and day shapes are tools used to indicate the status of a vessel on the water and the direction in which it’s moving. It’s important to know a few basics so you can make safe decisions about how to manage your own boat and how to interpret the status of the vessels around you so you avoid a collision.

All boats have basic navigation lights (or boat running lights) for when they’re underway at night and those include red (port), green (starboard) and white (anchoring, steaming or stern). It gets more complicated when lights are used in different combinations to indicate the status of a boat whether underway or not. Day shapes are signals used during daylight hours (dawn to dusk) that correspond to the various configurations of lights used at nighttime. Both boat navigation lights and day shapes are defined by the International Regulations for Preventing Collisions at Sea (ColRegs) and you should be familiar with a few of the key ones whenever you go out on your boat.

 

Man Standing on Bow at Bayliner Trophy Center Console Fishing Boat Reeling in Fish

Know your boat’s navigation lights

Red, green, white, blue and yellow lights may be arranged in various combinations to help you determine what the boats around you are doing. Lights are specified as to the degrees or angles from which they are visible. Typically, placement should display a green starboard light on the right side and a red port light on the left side, both visible from ahead to 112.5 degrees aft on their respective sides. Additionally, a white stern light should be positioned at the rear, visible from 135 degrees on either side.

Some common combinations include:

  • All-around (360 degrees) white light: Vessel anchored.
  • Red over green: Vessel sailing.
  • Red over red: Vessel not under command.
  • Red over white: Vessel engaged in commercial fishing.
  • Green over white: Vessel actively engaged in trawling.
  • White over red: Harbor pilot.
  • White over white: Vessel towing – short tow.
  • White over white over white: Vessel towing – long tow.
  • Red over white over red: Vessel restricted in ability to maneuver.
  • Red over red over red: Vessel restricted by draft.
  • Yellow (amber) lights: Designate vessel towing/pushing or a submarine depending on how displayed.
  • Blue lights: Authority vessel such as a police boat.

    • Always consult local maritime authorities for specific boat navigation light and day shape guidelines in your area.

    Man Driving Bayliner Deck Boat, Women Riding at Bow and Stern, Starboard View, Boat Underway

    Understanding different day shapes

    Day shapes are shown at the masthead or in the “rigging” from dawn to dusk. On small boats, that means as high up as possible but vessels under 7 meters (23 feet) and in some cases 12 meters (39 feet) aren’t typically required to display day shapes. Even if you don’t need to display them, you should know what they mean to understand what is happening with the vessels around you.

    Day shapes are black geometric shapes (ball, cone, cylinder and diamond) that can be used alone or in various combinations to denote a different vessel status. Some common ones include:

  • One black ball: Vessel anchored.
  • Two black balls displayed vertically: Vessel not under command.
  • Three black balls displayed vertically: Vessel aground.
  • Three balls in a cross formation: Minesweeper.
  • One cone pointing downward: Vessel under sail.
  • Two cones pointing toward each other: Vessel engaged in commercial fishing.
  • One diamond: Vessel towing.
  • One ball, one diamond, one ball arranged vertically: Vessel restricted in its ability to maneuver.
  • One cylinder: Vessel constrained by draft.

    • Bonus boater tip

    To remember the basics of port and starboard try this: “Port” has four letters as does the word “left” and port wine is red. If you see a red and green, the vessel is coming head on. If you see a white light only, the vessel is moving away from you or is anchored. If you see a red light (with or without a white behind it) that vessel is coming from your right and has the right of way in a crossing situation.

    For more complex boat navigation light and day shape configurations, a useful tool is the LIGHTrule from Weems and Plath. Shaped like a large slide rule, it identifies 60 light combinations from bow, stern, port and starboard angles, and 15 corresponding day shapes. It even includes sound signals used in fog or during times of limited visibility. Keep the LIGHTrule aboard for quick reference throughout the boating season.

    Understanding how vessels communicate via lights and shapes is important knowledge you need to avoid a collision. You don’t need to know each combination, but you should be familiar with a few to stay safe on your boat.