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Navigation Lights Quiz: 10 Real USCG Exam Questions

Think you know your lights? Here are 10 navigation lights questions pulled word for word from the USCG Rules of the Road question bank. Answer each one in your head, then tap "Show answer" to check yourself and see the rule behind it.

Every question here applies under both International and Inland rules. Explanations are checked against the 2022 U.S. Coast Guard Navigation Center (NAVCEN) Navigation Rules handbook.

The quiz

Question 1. BOTH INTERNATIONAL & INLAND Two all-round red lights displayed in a vertical line are shown by a vessel __________.

  1. being towed
  2. pushing a barge ahead
  3. at anchor
  4. not under command
Show answer

D. not under command

A vessel not under command shows two all-round red lights in a vertical line where they can best be seen. If she is making way, she adds sidelights and a stern light. See Rule 27(a)(i).

Question 2. BOTH INTERNATIONAL & INLAND A vessel showing a green light over a white light in a vertical line above the level of the sidelights is __________.

  1. engaged in underwater construction
  2. under sail and power
  3. a pilot vessel
  4. trawling
Show answer

D. trawling

Green over white is trawling. Red over white is fishing other than trawling. Memory hook: "green over white, trawling tonight; red over white, fishing at night." See Rule 26(b)(i).

Question 3. BOTH INTERNATIONAL & INLAND A vessel shall be deemed to be overtaking when she can see at night __________.

  1. only the stern light of the vessel
  2. a sidelight and one masthead light of the vessel
  3. only a sidelight of the vessel
  4. any lights except the masthead lights of the vessel
Show answer

A. only the stern light of the vessel

You are overtaking when you come up from more than 22.5 degrees abaft the other vessel's beam, which at night means you can see only her stern light and neither sidelight. See Rule 13(b).

Question 4. BOTH INTERNATIONAL & INLAND What describes a head-on situation?

  1. Seeing a vessel displaying both sidelights ONLY dead ahead
  2. Seeing two forward white towing identification lights in a vertical line on a towing vessel directly ahead
  3. Seeing both sidelights of a vessel directly off your starboard beam
  4. Seeing both sidelights and masthead light(s) of a vessel dead ahead
Show answer

D. Seeing both sidelights and masthead light(s) of a vessel dead ahead

At night a head-on situation means you see the masthead light or lights in a line or nearly in a line and/or both sidelights of a vessel ahead or nearly ahead. See Rule 14(b).

Question 5. BOTH INTERNATIONAL & INLAND A vessel towing is showing three forward white masthead lights in a vertical line. This means that the length of the __________.

  1. towing vessel is less than 50 meters
  2. towing vessel is greater than 50 meters
  3. tow is less than 200 meters
  4. tow is greater than 200 meters
Show answer

D. tow is greater than 200 meters

A towing vessel shows two masthead lights in a vertical line, or three when the tow, measured from the stern of the towing vessel to the after end of the tow, is longer than 200 meters. See Rule 24(a)(i).

Question 6. BOTH INTERNATIONAL & INLAND At night, which lights are required to be shown by a dredge on the side of the dredge which another vessel may pass?

  1. One red light
  2. Two red lights
  3. One white light
  4. Two green lights
Show answer

D. Two green lights

A dredge with an obstruction shows two all-round red lights on the obstructed side and two all-round green lights on the side another vessel may pass. Green means go. See Rule 27(d)(ii).

Question 7. BOTH INTERNATIONAL & INLAND At night, a power-driven vessel less than 12 meters in length may, instead of the normal navigation lights, show sidelights and one __________.

  1. white light
  2. yellow light
  3. flashing white light
  4. flashing yellow light
Show answer

A. white light

A power-driven vessel under 12 meters may show an all-round white light and sidelights instead of a separate masthead light and stern light. See Rule 23.

Question 8. BOTH INTERNATIONAL & INLAND Which lights are shown by a vessel restricted in her ability to maneuver to indicate that the vessel is making way?

  1. Masthead lights, sidelights and stern light
  2. Masthead lights and sidelights only
  3. Sidelights and stern light only
  4. Sidelights only
Show answer

A. Masthead lights, sidelights and stern light

A vessel restricted in her ability to maneuver shows red, white, red all-round lights. When making way through the water she adds masthead lights, sidelights and a stern light. See Rule 27(b)(iii).

Question 9. BOTH INTERNATIONAL & INLAND A "flashing light" is a light that __________.

  1. flashes at regular intervals at a frequency of 120 flashes or more per minute
  2. is yellow in color
  3. is visible over an arc of the horizon of not less than 180° nor more than 225°
  4. All of the above
Show answer

A. flashes at regular intervals at a frequency of 120 flashes or more per minute

Rule 21 defines a flashing light as one flashing at regular intervals at a frequency of 120 flashes or more per minute. Color and arc are not part of the definition. See Rule 21(f).

Question 10. BOTH INTERNATIONAL & INLAND An all-round flashing yellow light may be exhibited by a(n) __________.

  1. vessel not under command
  2. air cushion vessel in the nondisplacement mode
  3. vessel towing a submerged object
  4. vessel engaged in diving operations
Show answer

B. air cushion vessel in the nondisplacement mode

An air-cushion vessel operating in the nondisplacement mode shows an all-round flashing yellow light in addition to her normal power-driven lights. See Rule 23(b).

How did you do?

If you got 9 or 10, you're in good shape on lights. If you missed a few, start with the navigation lights cheat sheet, then the full lights and shapes study guide. For the daytime version, see COLREGS day shapes.

Want the rest of the lights questions? Practice every lights and shapes question in the USCG bank, including the diagram questions, with missed-question review in COLREGS: Rules of the Road for iPhone and iPad. Download on the App Store

Prefer the browser? The free web study tool has all 1,272 questions.

Frequently asked questions

Are these real USCG exam questions?

Yes. All 10 come word for word from the USCG Rules of the Road question bank, the same 1,272 questions used in COLREGS Prep.

How many navigation lights questions are on the Rules of the Road exam?

Lights questions are one of the biggest topics in the bank. In COLREGS Prep, more than 250 of the questions that apply to both International and Inland waters are tagged as lights questions, before counting the ones with diagrams.

What is the easiest way to learn navigation lights?

Learn the building blocks first (masthead, sidelights, stern light, all-round lights), then learn the special signals by color: red over red for not under command, red-white-red for restricted, green over white for trawling, red over white for other fishing.

Keep studying