How to Pass the USCG Rules of the Road Exam Section (COLREGS)

Why Rules of the Road Is Different

Every section of the USCG captain's license exam requires a 70% passing score — except one. The Rules of the Road (COLREGS) section requires 90%. Miss more than one out of ten questions and you fail the whole section, even if you aced everything else.

The Coast Guard is not making this hard for fun. The International Regulations for Preventing Collisions at Sea — COLREGS — are the foundational legal framework for avoiding ships running into each other at night, in fog, and in congested waterways. When these rules break down, people die. The USCG holds captains to a higher standard on this material because the stakes of getting it wrong at sea are irreversible.

In my experience teaching USCG exam prep, COLREGS is the section that fails more students than any other. It's also the section where focused study pays off fastest — because unlike chart work or celestial navigation, Rules of the Road is primarily conceptual and logical. Once the framework clicks, questions become predictable.

The Most Tested Rules: Know These Cold

The exam doesn't test all 41 COLREGS rules equally. These are the ones that appear on virtually every exam:

Rule 5 — Look-Out

"Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision."

This sounds simple but generates a lot of exam questions about what "proper" means in various conditions — restricted visibility, high traffic, at anchor. Know that a proper lookout is always required and that a single person cannot simultaneously serve as lookout and helmsman on a busy vessel.

Rule 8 — Action to Avoid Collision

Actions must be positive, made in ample time, and large enough to be readily apparent to the other vessel. The exam loves to test the "readily apparent" requirement — a small course change that the other vessel cannot detect is not a proper action under Rule 8. When in doubt, make bold maneuvers.

Rules 13-17 — The Overtaking and Crossing Rules

These define who gives way and who stands on in various encounter situations:

• Rule 13 (Overtaking): Any vessel overtaking another is the give-way vessel, regardless of what types of vessels are involved. The overtaking vessel must keep clear until finally past and clear.
• Rule 14 (Head-On): Both vessels alter course to starboard when meeting head-on. The classic "red-to-red" rule.
• Rule 15 (Crossing): The vessel with the other on her starboard side is the give-way vessel. Think of it as the vessel on the right having right of way — the vessel on its left must give way.
• Rule 16 (Give-Way Vessel): Must take early and substantial action to keep well clear.
• Rule 17 (Stand-On Vessel): Must maintain course and speed. But — crucially — if the give-way vessel fails to act, the stand-on vessel must take action to avoid collision. This is the most tested nuance in this cluster.

Rule 18 — Responsibilities Between Vessels

This is the vessel hierarchy rule — the master rule that governs which type of vessel gives way to which. Memorize this hierarchy from most privileged (least burdened) to least privileged (most burdened):

1. Vessel Not Under Command (NUC)
2. Vessel Restricted in Ability to Maneuver (RAM)
3. Vessel Constrained by Draft (CBD)
4. Vessel Engaged in Fishing (with gear deployed)
5. Sailing vessel
6. Power-driven vessel underway

A power-driven vessel gives way to all of the above. A sailing vessel gives way to NUC, RAM, CBD, and fishing vessels. Note that a vessel "constrained by draft" only applies in narrow channels and is an International Rules concept — it doesn't appear in the Inland Rules.

A common exam trick: a vessel displaying CBD lights in open water is still just a power-driven vessel for rule purposes. CBD only applies when a vessel's draft relative to the available depth genuinely restricts her ability to deviate from the channel.

Light Patterns That Appear Most on the Exam

Navigation lights questions make up a significant portion of the COLREGS section. The exam typically shows you a diagram of lights and asks you to identify the vessel type, or describes a vessel situation and asks what lights are displayed.

Essential light configurations to know:

• Power-driven vessel under 50m: Masthead light (225° forward arc), sidelights (port red 112.5°, starboard green 112.5°), sternlight (135° white)
• Power-driven vessel over 50m: Same as above plus a second masthead light aft and higher than the forward masthead light
• Sailing vessel underway: Sidelights and sternlight only — no masthead light. Optionally, a tri-color masthead light instead (but not both)
• Vessel at anchor: All-round white light (vessels under 50m: one all-round white; over 50m: all-round white forward and all-round white or less bright white aft)
• NUC: Two all-round red lights in a vertical line
• RAM: Ball-diamond-ball shape by day; red-white-red all-round vertical lights at night
• Trawler (fishing): Green-over-white all-round lights (the "Christmas tree") when trawling; red-over-white when other fishing gear is deployed
• Pilot vessel: White-over-red all-round lights

Sound Signals

Sound signals show up reliably on the exam. The key ones:

• One short blast: I am altering course to starboard
• Two short blasts: I am altering course to port
• Three short blasts: I am operating astern propulsion
• Five or more short rapid blasts: Danger signal (the other vessel's actions are unclear or insufficient)
• In restricted visibility (fog): Power-driven vessels sound one prolonged blast every 2 minutes; vessels not under command or restricted in ability to maneuver sound one prolonged and two short blasts every 2 minutes

A critical distinction: the Inland Rules use sound signals as agreement signals (one blast means "I intend to pass port-to-port, do you agree?") while the International Rules treat them as action signals ("I am altering to starboard"). The exam will specify whether you're in Inland or International waters — read the question carefully.

Top Mistakes Students Make

After teaching this material to many students, these are the errors I see repeatedly:

1. Confusing Inland vs. International sound signals. They work differently. Always identify which set of rules applies before answering a sound signal question.
2. Forgetting that overtaking always applies. Rule 13 overrides the crossing rules. If you're catching up to another vessel, you're overtaking — even if the geometry looks like a crossing situation.
3. Not knowing that the stand-on vessel must eventually act. Rule 17 doesn't mean you hold course until collision. If the give-way vessel isn't acting, you must take action. Many students think "stand-on" means "stay put no matter what."
4. Mixing up RAM and NUC. NUC means the vessel cannot maneuver due to an exceptional circumstance (engine failure, steering failure). RAM means the nature of the work restricts the vessel's ability to maneuver (dredging, mine-clearing, cable laying). RAM vessels are still under command — they're just doing something that prevents them from getting out of your way.
5. Light arc degrees. Forgetting exact arc degrees kills exam scores. Masthead: 225°. Stern: 135°. Sidelights: 112.5° each. All-round: 360°.

A 3-Week Study Strategy

This is the approach I recommend to every student who comes through my prep sessions:

Week 1 — Framework. Read Rules 1-19 in full. Don't memorize — understand. Focus on the logic. Why does a sailing vessel give way to a fishing vessel with gear deployed? Because the fishing vessel has less ability to maneuver. The rules have an internal logic. Once you see it, the hierarchy becomes intuitive.

Week 2 — Details. Memorize light configurations and arc degrees. Memorize sound signals. Do 20-30 practice questions per day, reading every explanation — even for questions you got right. Understanding why the right answer is right is as important as getting it right.

Week 3 — Drilling for 90%. Take full COLREGS practice sets daily. You need to hit 90% consistently before exam day — not occasionally. If you're scoring 80-85%, identify exactly which rules are tripping you up and go back to the source text. At this point, a missed question should send you directly to the actual COLREGS rule, not a summary.

The COLREGS text itself is freely available online from the USCG. Read the actual rules, not just study guides. The exam draws from exact rule language.

Tools That Help

The free COLREGS Quick Reference Sheet here on The Chartroom summarizes the key rules, vessel hierarchy, and light configurations in a format you can print and drill with. The Rules of the Road practice tool lets you drill individual rules until you're consistent.

The most important thing I can tell you about passing the COLREGS section: don't treat it as memorization. Treat it as learning a system of logic. Vessels in trouble get right of way over vessels that can maneuver. Bold action beats hesitation. The stand-on vessel still has to avoid a collision if the other vessel fails to act. That logic runs through all 41 rules. Once you see it, the 90% becomes achievable — and then routine.