Anchor Light Requirements

The Inland Rules have specific requirements as to anchor lights. That rule is quoted below, as is the USCG site reference.

A 360-degree white all-around masthead light with two-mile visibility normally fulfills this requirement for most pleasure boats, but familiarize yourself with and follow the rule. Wire gauge, length of wiring, connections and battery condition can affect a light's performance. Follow manufacturer's instructions to ensure compliance with U.S. Coast Guard regulations. If you have one of the newer LED anchor lights, it may not be as bright as earlier lights. Be sure that the manufacturer specifies in writing that it meets USCG requirement.

Displaying a proper anchor light when anchored at night isn't merely a matter of law. It's a matter of safety for you and others. Even if the boat is in a known or designated anchorage area, dinghies and other boats may be traveling in that area and will need to know the location of your boat. People have been severely injured and killed because a skipper decided that he'd not burn an anchor light.

Following is Rule 30 of the Rules found here.

Rule 30 - Anchored Vessels and Vessels Aground

(a) A vessel at anchor shall exhibit where it can best be seen:

(i) in the fore part, an all-round white light or one ball;

(ii) at or near the stern and at a lower level than the light prescribed in subparagraph (i), an all-round white light.

(b) A vessel of less than 50 meters in length may exhibit an all-round white light where it can best be seen instead of the lights prescribed in paragraph (a) of this Rule.

(c) A vessel at anchor may , and a vessel of 100 meters and more in length shall, also use the available working or equivalent lights to illuminate her decks.

(d) A vessel aground shall exhibit the lights prescribed in paragraph (a) or (b) of this Rule and in addition, if practicable, [Inld] where they can best be seen;

(i) two all-round red lights in a vertical line;

(ii) three balls in a vertical line.

(e) A vessel of less than 7 meters in length, when at anchor not in or near a narrow channel, fairway or where other vessels normally navigate, shall not be required to exhibit the shape prescribed in paragraphs (a) and (b) of this Rule.

(f) A vessel of less than 12 meters in length, when aground, shall not be required to exhibit the lights or shapes prescribed in subparagraphs (d)(i) and (ii) of this Rule.

(g) A vessel of less than 20 meters in length, when at anchor in a special anchorage area designated by the Secretary, shall not be required to exhibit the anchor lights and shapes required by this Rule. [Inld]