COLREGs Rule 30: Anchored vessels and vessels aground lights

Last reviewed: October 14, 2026

Rule 30 sets the lights and shapes a vessel at anchor or aground must exhibit. Small vessels have exceptions. The Inland rule adds provisions for special anchorage areas and for moored barges.

Applies toVessels at anchor and vessels aground; the Inland rule also applies to certain barges.

What it says

  1. A vessel at anchor must exhibit, where it can best be seen, an all-round white light or one ball in the fore part.

    COLREGs Rule 30(a)“A vessel at anchor shall exhibit where it can best be seen:”

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

    COLREGs Rule 30(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.”

  3. International: A vessel at anchor may use available working or equivalent lights to illuminate her decks, and a vessel of 100 meters and more in length shall do so.

    COLREGs Rule 30(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.”

  4. International: A vessel aground must exhibit the anchor lights from paragraph (a) or (b) and, where they can best be seen, two all-round red lights in a vertical line or three balls in a vertical line.

    COLREGs Rule 30(d)“A vessel aground shall exhibit the lights prescribed in paragraph (a) or (b) of this Rule and in addition, where they can best be seen:”

  5. Inland: A vessel aground must exhibit the anchor lights and, if practicable, the added red lights and balls.

    COLREGs Rule 30(d)“A vessel aground shall exhibit the lights prescribed in paragraph (a) or (b) of this Rule and in addition, if practicable, where they can best be seen:”

  6. A vessel of less than 7 meters in length at anchor need not exhibit anchor lights or shape, if it is not in or near a narrow channel, fairway or anchorage, or where other vessels normally navigate.

    COLREGs Rule 30(e)“A vessel of less than 7 meters in length, when at anchor, not in or near a narrow channel, fairway or anchorage, or where other vessels normally navigate,”

  7. Inland: A vessel of less than 20 meters in length at anchor in a special anchorage area designated by the Coast Guard need not exhibit the anchor lights and shapes required by this Rule.

    COLREGs Rule 30(g)“A vessel of less than 20 meters in length, when at anchor in a special anchorage area designated by the Coast Guard ‡, shall not be required to exhibit”

  8. Inland: Barges described in paragraph (h) must carry two unobstructed all-round white lights visible for at least 1 nautical mile and meeting Annex I (33 CFR part 84).

    COLREGs Rule 30(i)“Barges described in paragraph (h) of this Rule shall carry two unobstructed all-round white lights of an intensity to be visible for at least 1 nautical mile”

Common questions

What lights must an anchored vessel show?

A vessel at anchor must exhibit an all-round white light or one ball in the fore part. It must also show an all-round white light at or near the stern, at a lower level.

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

Does a small vessel aground need to show red lights or balls?

A vessel of less than 12 meters in length when aground is not required to exhibit the red lights or balls.

“A vessel of less than 12 meters in length, when aground, shall not be required”

When must an anchored vessel light its decks?

A vessel at anchor may use working lights to illuminate her decks. International: a vessel of 100 meters and more in length must do so; Inland: 100 meters or more.

“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.”

The text of COLREGs Rule 30

U.S. Coast Guard, Navigation Rules and Regulations Handbook

Rule 30: Anchored Vessels and Vessels Aground

International (COLREGs)

(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. Vessel at anchor—less than 50 meters in length. Same for Inland.

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

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

(ii) three balls in a vertical line. Vessel aground. Same for Inland.

(e) A vessel of less than 7 meters in length, when at anchor, not in or near a narrow channel, fairway or anchorage, or where other vessels normally navigate, shall not be required to exhibit the lights or 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.

Inland Rules

Vessels anchored, aground and moored barges

(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 paragraph (i) of this Rule, 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 or more in length shall, also use the available working or equivalent lights to illuminate her decks. Vessel at anchor with deck illumination. Same for International.

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

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

(ii) Three balls in a vertical line. Vessel aground—less than 50 meters in length. Same for International.

(e) A vessel of less than 7 meters in length, when at anchor, not in or near a narrow channel, fairway, anchorage, or where other vessels normally navigate, shall not be required to exhibit the lights or 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 paragraphs (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 Coast Guard ‡, shall not be required to exhibit the anchor lights and shapes required by this Rule.

(h) The following barges shall display at night and if practicable in periods of restricted visibility the lights described in paragraph (i) of this Rule:

(i) Every barge projecting into a buoyed or restricted channel.

(ii) Every barge so moored that it reduces the available navigable width of any channel to less than 80 meters.

(iii) Barges moored in groups more than two barges wide or to a maximum width of over 25 meters.

(iv) Every barge not moored parallel to the bank or dock. ‡ See 33 CFR 110 Subpart A

(i) Barges described in paragraph (h) of this Rule shall carry two unobstructed all-round white lights of an intensity to be visible for at least 1 nautical mile and meeting the technical requirements as prescribed in Annex I (33 CFR part 84).

(j) A barge or a group of barges at anchor or made fast to one or more mooring buoys or other similar device, in lieu of the provisions of this Rule, may carry unobstructed all-round white lights of an intensity to be visible for at least 1 nautical mile that meet the requirements of Annex I (33 CFR part 84) and shall be arranged as follows:

(i) Any barge that projects from a group formation, shall be lighted on its outboard corners.

(ii) On a single barge moored in water where other vessels normally navigate on both sides of the barge, lights shall be placed to mark the corner extremities of the barge.

(iii) On barges moored in group formation, moored in water where other vessels normally navigate on both sides of the group, lights shall be placed to mark the corner extremities of the group.

(k) The following are exempt from the requirements of this Rule:

(i) A barge or group of barges moored in a slip or slough used primarily for mooring purposes.

(ii) A barge or group of barges moored behind a pierhead.

(iii) A barge less than 20 meters in length when moored in a special anchorage area designated in accordance with § 109.10 of this chapter.

(l) Barges moored in well-illuminated areas are exempt from the lighting requirements of this Rule. These areas are as follows: CHICAGO SANITARY (18) Mile 316.8 CALUMET RIVER SHIP CANAL (19) Mile 316.85 to 317.05 (31) Mile 328.5 to 328.7

(1) Mile 293.2 to 293.9 (20) Mile 317.5 (32) Mile 329.2 to 329.4

(2) Mile 295.2 to 296.1 (21) Mile 318.4 to 318.9 (33) Mile 330 west bank to

(3) Mile 297.5 to 297.8 (22) Mile 318.7 to 318.8 330.2

(4) Mile 298 to 298.2 (23) Mile 320 to 320.3 (34) Mile 331.4 to 331.6

(5) Mile 298.6 to 298.8 (24) Mile 320.6 (35) Mile 332.2 to 332.4

(6) Mile 299.3 to 299.4 (25) Mile 322.3.6 to 322.4 (36) Mile 332.6 to 332.8

(7) Mile 299.8 to 300.5 (26) Mile 322.8

(8) Mile 303 to 303.2 (27) Mile 322.9 to 327.2 CUMBERLAND

(9) Mile 303.7 to 303.9 RIVER

(10) Mile 305.7 to 305.8 CALUMET SAG (37) Mile 126.8

(11) Mile 310.7 to 310.9 CHANNEL (38) Mile 191

(12) Mile 311 to 311.2 (28) Mile 316.5

(13) Mile 312.5 to 312.6

(14) Mile 313.8 to 314.2 LITTLE CALUMET

(15) Mile 314.6 RIVER

(16) Mile 314.8 to 315.3 (29) Mile 321.2

(17) Mile 315.7 to 316 (30) Mile 322.3

Sections it refers to

  • 33 CFR part 84
  • 33 CFR 110 Subpart A

The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of August 12, 2024. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.