Navigation Lights

One of our readers is undertaking a total rebuild of an old Chris-Craft. Along with a few concerns about boat wiring, he also asked us for a quick rundown of his navigation light requirements for the project.

There are a number of on-line references for this info. As you would expect, Attwood, the industry’s top manufacturer of these lights, provides one of the best. According to their site, there are

“…four basic types of navigation lights, differentiated by lens color, beam angle (horizontal cut-off angle), and location on the boat. All lights are for 12-volt DC applications only. Styles may vary, but the color, cut-off angle, and location must always comply with the following standards:

Attwood then goes on to define the four basic navigation lights as:


Color: red port, green starboard. Cut-off: from dead ahead to 112.5° aft on either side of center line (225° total horizontal arc)

All-Round Lights

For boats less than 12 meters (39.4 feet). The white all-round light may be used in lieu of the masthead and transom light. Color: white. Cut-off: unbroken arc of 360° on the horizon. Mounting: As near to the fore and aft centerline as possible.

Masthead Lights

Color: white. Cut-off: unbroken arc from dead ahead to 112.5° aft on either side of center line (225° total horizontal arc). Mounting: Placed over the fore and aft centerline.

Transom Lights

Color: white. Cut-off: unbroken horizontal arc of 67.5° each side dead astern (135° total horizontal arc). Mounting: As far aft as possible.

The size, type and disposition of the boat being lighted dictates which of these lights are to be installed – and when they are to be used. Here are the general rules:

Boats At Anchor
When anchored in other than designated areas, any boat under 50 meters (164 feet) must have a 360° white light in view (a single all-round light, or a masthead and transom light, or other means).

Power Boats Underway

Power-driven boats less than 12 meters (39.4 feet) with maximum speed over 7 knots are required to use a:

  • Sidelight pair or combined-1 mile
  • All-Round Light-2 mile; or
  • Masthead Light-2 mile with Transom Light-2 mile.
  • Larger powerboats, those measuring from 12 to 20 meters (39.4 to 65.6 feet), must use a

  • Sidelight pair or combined-2 mile;
  • Masthead Light-3 mile; and Transom Light-2 mile.
  • All-Round Light may not be used.
  • Sailboats Under Motor Power

    When under power, sailboats are considered power boats and must operate with power boat lights as outlined above.

    As for those times when the boat is exclusively under sail:

    Sailboats less than 12 meters (39.4 feet) under sail:

  • Sidelight pair or combined-1 mile;
  • Transom Light-2 mile; flashlight or lighted lantern
  • Sailboats 12 to 20 meters (39.4 to 65.6 feet) under sail

    On these larger sailboats, 3 different light configurations may be acceptable:

  • Sidelights & Transom Light or
  • A Sidelight & Transom Light combined in one light (a Tri-Color Light) mounted at or near top of mast or
  • Sidelights & Transom Light, or two All-Round Lights, mounted at or near the top of the mast, the upper light being red and the lower green.
  • And, finally, for those readers who are rebuilding on a somewhat smaller scale…

    Small, Oar-Driven Boats

  • Sidelight pair or combined, 1 mile
  • Transom Light-2 mile; flashlight or lighted lantern
  • According to Attwood, various other light requirements are outlined in the standards regarding towing, vessels aground, and other special conditions. Consult the Inland Navigation Rules, 72 COLREGS, or USCG for details.

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