Bottom line: build the UAMS domain around a decision loop — classify the vessel, judge risk of collision, assign stand-on or give-way status, choose the maneuver, name the signal. Drill the Inland-versus-International divergences, whistle signals, aids to navigation, and the navigation publications as separate skills, then combine them in paper contact scenarios. For administrative details such as endorsement applications and testing arrangements, consult the U.S. Coast Guard National Maritime Center directly.
Why Reciting Rule Text Breaks Down When a Contact Appears on the Bow
The rules domain rewards a decision sequence, not quotations: classify the vessel, assess risk, assign stand-on or give-way status, choose an action, and identify the signal. Practicing that loop turns rule text into usable conning decisions.
Rule 7 defines risk of collision operationally: use every available means, and if a compass bearing of an approaching vessel does not appreciably change, risk shall be deemed to exist. In a paper scenario, practice the observation first — record two successive bearings of the contact and note whether they drift. This grounds the rule in something checkable, and it mirrors the plotting habit of drawing the contact's true bearing line to see whether it rotates as range closes.
The loop also prevents an ordering error: choosing a maneuver before assigning a role. Rules 13, 15, and 18 assign roles; Rules 16 and 17 then say what each role owes. When you rehearse a contact card, write the role down before considering any alteration of course. If new facts change the classification — a vessel you took for constrained becomes not under command, for example — restart the loop from the classification step instead of patching the old answer.
Assigning Stand-On and Give-Way Roles in Crossing and Overtaking Situations
Rule 13 makes the overtaking vessel give-way whatever the angle of approach, and Rule 15 makes the crossing power-driven vessel that has the other on her starboard side give-way. Name your role first; the maneuver follows from it.
Scenario 1 (paper exercise): you are conning a power-driven vessel when another power-driven vessel bears broad on your starboard bow; range is closing and the bearing is steady. A tempting mistake is assuming the larger or slower vessel must yield, then altering to port to 'stay clear of everything.' The better decision: the other vessel is on your starboard side, so Rule 15 makes you the give-way vessel. Sound one short blast, alter to starboard early and substantially, and pass astern of the other vessel rather than crossing ahead of her. This matters because Rule 16 requires early, substantial, easily observable action, and crossing ahead cancels the benefit of that action by prolonging the encounter.
Overtaking carries a nuance worth isolating in your notes: Rule 13 covers a vessel approaching from more than 22.5 degrees abaft the beam, and adds that a vessel which cannot determine whether she is overtaking shall be deemed to be overtaking. The role then survives angle changes — an overtaking vessel that draws abeam of the stand-on vessel remains give-way until finally past and clear. When drilling, deliberately include contacts near that 22.5-degree boundary so you must state which clause resolves the ambiguity before you answer.
Inland Versus International Rules: Four Differences That Flip an Answer
The two texts share structure but diverge in details that decide answers: the narrow-channel overtaking agreement, the constrained-by-draft category, the leaving-dock signal, and towed barge lighting. Identify which text governs before answering any signal or precedence question.
Both texts apply to U.S. mariners, but in different waters: the Inland rules govern navigable waters of the United States inside the demarcation lines drawn for that purpose, and the International rules (COLREGS) apply beyond them. The core steering-and-sailing content is closely aligned, which is exactly why the divergences are instructive — a rule answered from the wrong text fails even though the general principle was understood. Build the habit of asking 'which text governs this water?' before any signal question.
A practical study method: annotate your rules copy at each divergent rule — 18, 25, and 34 are the core set — and write one sentence per rule stating how the Inland text differs. Make the difference itself the flashcard front, for example 'What signal must the vessel being overtaken sound in a narrow channel under the Inland rules?' The table below collects the differences most worth carrying into a scenario drill.
| Point of difference | International rules (COLREGS) | Inland rules |
|---|---|---|
| Overtaking agreement in a narrow channel | The vessel to be overtaken, if in agreement, sounds the same signal as the overtaking vessel and permits safe passing | The vessel to be overtaken, if in agreement, answers with one prolonged, one short, one prolonged, one short |
| Rule 18 precedence categories | Includes the vessel constrained by her draft | Constrained by draft is not a Rule 18 category |
| Signal on leaving a dock or berth | Not prescribed | One prolonged blast |
| Towed barge lighting | Standard stern, sidelight, and towing light provisions | Additional specific provisions for barges carried ahead or astern of a tug |
Whistle Signals: Matching the Blast Pattern to Maneuver, Doubt, and Overtaking
One short blast means altering course to starboard, two to port, and three astern propulsion; a short blast is about one second and a prolonged blast four to six seconds. Maneuvering signals are exchanged between vessels in sight of one another.
Scenario 2 (paper exercise): in a narrow channel, your vessel overtakes a slower tow from astern. You sound two prolonged blasts followed by one short blast, signaling an intention to pass on the tow's starboard side. A plausible mistake is treating silence as consent and beginning the pass — or sounding the one-prolonged, one-short, one-prolonged, one-short pattern yourself. The better decision: under Inland Rule 34(c), that agreement signal belongs to the vessel being overtaken; wait for it before committing, then conduct the pass while monitoring the bridge-to-bridge communication where it is required. The why: the rule assigns the answer to a specific vessel, and inventing it manufactures a false agreement that both bridges may act upon.
Round out the signal set deliberately: the doubt or danger signal is five or more short and rapid blasts; a vessel approaching a blind bend sounds one prolonged blast; and the Inland text adds one prolonged blast when leaving a dock or berth. In restricted visibility, Rule 35 governs: a power-driven vessel making way sounds one prolonged blast at intervals of not more than two minutes, and one not making way sounds two prolonged blasts with about a two-second interval. Tie each signal to a trigger condition, not to a memorized list position.
Lateral Aids to Navigation: Applying 'Red Right Returning' Without Guessing Shapes
Under the IALA Region B system, returning from sea you leave red markers to starboard and green to port; nuns are red with even numbers, cans green with odd numbers. Shape, color, number, and light rhythm should agree before you trust an aid.
Work the attributes as a set. Red nuns with even numbers mark the starboard side returning from sea; green cans with odd numbers mark the port side. Junction and preferred-channel markers combine both colors, so the topmark and the light rhythm carry the decision — and a quick-flashing or interrupted-quick-flashing rhythm on a junction marker points to the preferred channel. Safe-water marks and isolated-danger marks follow their own shape and color logic, so do not force lateral reasoning onto them.
Fixed daymarks follow the same color logic with shapes: red triangles and green squares. Two cautions belong in your notes. First, floating aids are moored and their positions are approximate, so a charted buoy is a guide, not a fix. Second, the chart is a snapshot — a printed chart can lag the current aid configuration, so reconcile any discrepancy against the Light List and Notice to Mariners rather than against memory. A drill that builds this: from a written aid description alone, sketch the aid and state the side on which you would leave it when returning from sea.
Light List, Coast Pilot, and Notice to Mariners: Which Publication Answers Your Question
The Light List describes aids — position, characteristic, height, range, structure; the Coast Pilot supplies local navigation knowledge; the Notice to Mariners carries corrections. Match each question's need to the right publication before hunting for details.
Sort the publications by the question they answer. Need an aid's exact light characteristic, structure, or nominal range? Light List. Need anchorage areas, local currents, prominent dangers, or facility notes for a coast? Coast Pilot. Need to know whether the chart or the aid description has changed? Notice to Mariners. Add the tide and tidal current tables for predictions, and the distinction becomes mechanical rather than a guess under time pressure.
A short lookup drill builds the mapping: given the description 'green can buoy No. 15, flashing green four seconds, at the outer channel edge,' list the Light List columns you would check to confirm it, then explain how a Notice to Mariners correction would be applied to the chart versus to your Light List copy. Expected observations from the drill: corrections flow to both the chart and the publications, and magenta notes on a chart typically point you to the Coast Pilot for the fuller story. If a lookup stalls, the stall is usually a vocabulary gap — characteristic abbreviations — not a search gap.
Building an Adaptable Study Sequence With a Self-Check Rubric
Work the rules first, signals and Inland differences second, aids and publications third, then mixed practice under time pressure. Score yourself on behavior-based checkpoints — role before maneuver, signal before action, publication before detail — not on raw question counts.
One adaptable sequence: weeks one and two, read the steering-and-sailing rules and re-run the five-step loop on paper contacts daily; weeks three and four, drill whistle signals and the Inland/International divergences as paired flashcards; week five, aids to navigation, chart symbols, and the publication lookups; week six, mixed sets answered against the clock. Shift the proportions toward whichever checkpoint below you cannot yet meet — the sequence is a scaffold, not a calendar contract.
Core exercise — the contact card drill: write ten short situations (two crossing, two overtaking, two narrow-channel, two restricted visibility, two open-ended), and for each record classification, the bearing observation behind your risk verdict, role, maneuver, and signal before checking any reference. You are ready to move from review to exam-style drilling when you can explain each divergent rule from memory, sketch the light picture implied by a paper scenario, and route a fact-finding question to the correct publication without hesitating. For endorsement applications and testing logistics, the Coast Guard National Maritime Center is the administrative authority.
- States the role before any maneuver on every contact card — 2 points
- Names a signal for every maneuver and for each visibility condition — 2 points
- Separates the Inland from the International answer on the divergent rules — 2 points
- Identifies an aid from color, shape, number, and light rhythm together — 2 points
- Routes each fact-finding question to the correct publication on the first try — 2 points
- Self-check milestones: 8 or more points signals readiness for mixed timed sets; 5-7 points means re-drill the weakest line; below 5 points, return to the per-topic sequence.
References and further reading
Use these references to explore the concepts and check the latest information from the relevant organizations.