ColRegs Study Guide
Everything you need to pass Rules of the Road on the USCG OUPV exam: right-of-way hierarchy, sound signals, lights reference, and Inland vs. International differences.
ColRegs Structure — The Parts
Essential Rule Numbers to Memorize
| Rule | Title |
|---|---|
| 2 | Responsibility |
| 5 | Lookout |
| 6 | Safe Speed |
| 7 | Risk of Collision |
| 8 | Action to Avoid Collision |
| 13 | Overtaking |
| 14 | Head-on |
| 15 | Crossing |
| 16 | Give-way vessel |
| 17 | Stand-on vessel |
| 18 | Responsibilities between vessels |
| 19 | Restricted visibility |
| 24 | Towing and pushing |
| 35 | Sound signals in restricted visibility |
Right-of-Way Hierarchy (Rule 18)
Each vessel type must give way to all vessels above it in the hierarchy. The lower a vessel is in the list, the more give-way duties it has.
| Rank | Vessel Type |
|---|---|
| 1 | Not Under Command (NUC) |
| 2 | Restricted in Ability to Maneuver (RAM) |
| 3 | Constrained by Draft |
| 4 | Fishing / Trawling |
| 5 | Under Sail (when also using engine = power) |
| 6 | Power-driven underway |
| 7 | Seaplane |
Green = highest privilege; Red = most give-way duties
Navigation Light Arcs Reference
| Light | Arc | Color |
|---|---|---|
| Masthead (steaming) light | 225° | White |
| Sidelights | 112.5° each | Red (port), Green (starboard) |
| Stern light | 135° | White |
| All-around light | 360° | White (or red/green for special vessels) |
| Yellow towing light | 135° | Yellow |
| Flashing yellow (air-cushion) | 360° | Yellow |
Sound Signals Reference
| Signal | Meaning |
|---|---|
| 1 short blast | I am altering my course to starboard |
| 2 short blasts | I am altering my course to port |
| 3 short blasts | My engines are going astern |
| 5 or more short blasts | Danger — I do not understand your intentions / I doubt you are taking sufficient action |
| 1 prolonged blast | Vessel leaving a berth or dock (Inland) / Power vessel in restricted visibility (International) |
| 1 prolonged + 1 short | I intend to overtake you on your starboard side (Inland) |
| 1 prolonged + 2 short | I intend to overtake you on your port side (Inland) / Towing vessel in restricted visibility |
| 1 prolonged + 3 short | Vessel being towed in restricted visibility |
| 4 short blasts | Pilot vessel signal (identity) |
| Rapid bell ringing (5 seconds, every minute) | Vessel at anchor in restricted visibility |
Inland vs. International Key Differences
Must sound 1-long + 1-short (starboard) or 1-long + 2-short (port) AND wait for agreement (1-long+1-short or 1-long+2-short back) before passing
Overtaking vessel sounds 2-long + 1-short (starboard) or 2-long + 2-short (port); no agreement required
1-short (starboard), 2-short (port) — agreement signals required before altering
1-short = altering to starboard (action already taken or about to be taken)
Ring bell for 5 seconds every minute, plus optional gong, plus may sound 3 distinct tones to warn approaching vessel
Same bell ringing, plus optional gong; 3-tone warning signal also permitted
Additional passing rules apply on designated rivers; crossing vessel always gives way regardless of bearing
No equivalent — international rules apply on high seas only
Not recognized as a privileged class under Inland Rules
Rule 28 recognizes CBD vessels; 3 all-around red lights
Frequently Asked Questions
What passing score is required for Rules of the Road on the OUPV exam?
Rules of the Road requires 90% to pass on the OUPV exam — you can miss only 5 of 50 questions. This is the highest passing threshold of any OUPV section. All other sections require 70%. This is why Rules of the Road demands disproportionate study time.
What is the difference between Inland Rules and International Rules (ColRegs)?
International ColRegs apply on the high seas and international waters. U.S. Inland Rules apply in U.S. harbors, rivers, and inland waters (generally inside the demarcation lines). Key differences: Inland Rules require whistle signals for meeting/crossing/overtaking in sight of each other (1-short = starboard, 2-short = port, 3-short = astern, 5-short = danger); International Rules use these signals differently. Western Rivers rules add specific passing signals. Distress signals and some light configurations also differ slightly.
How do you memorize the ColRegs rule numbers?
The most useful mnemonic for rule numbers: Rule 2 (Responsibility), Rule 5 (Lookout), Rule 6 (Safe Speed), Rule 7 (Risk of Collision), Rule 8 (Action to Avoid), Rule 13 (Overtaking), Rule 14 (Head-on), Rule 15 (Crossing), Rule 16 (Give-way), Rule 17 (Stand-on), Rule 18 (Responsibilities between vessels), Rule 19 (Restricted Visibility). For lights: Rule 20 (application), Rule 21 (definitions), Rule 22 (visibility of lights), Rule 23 (power-driven underway), Rule 24 (towing). Study the structure: Parts A (General), B (Steering), C (Lights), D (Sound), E (Exemptions).
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