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Boating Navigation Rules curriculum

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197 concepts
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Everything the adaptive question bank can teach and test in Boating Navigation Rules, from foundations through advanced practice. Work through it in order, or start practising and let the questions find your level.
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A free 14-minute primer — the mental model, the mistakes beginners make, and what to practise first.
A. Foundations (Rules 2, 5–8, 17)
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The two roles defined; hold course/speed vs early and substantial action.
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Sight AND hearing, at all times, every vessel.
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The factors: visibility, traffic, stopping distance, night background light, wind/sea/current, draft.
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Risk of collision: constant bearing, decreasing range.
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Ample time, readily apparent, avoid a succession of small alterations.
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No rule excuses neglect; departure allowed to avoid immediate danger.
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May act when give-way clearly isn't acting; must act in extremis; avoid turning port for a vessel on own port side.
B. Meeting, crossing & overtaking (Rules 13–15)
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Both power vessels alter starboard, pass port-to-port; night cue: both sidelights plus masthead lights.
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The vessel with the other on her STARBOARD side gives way; avoid crossing ahead.
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The overtaking vessel ALWAYS gives way — even sail overtaking power; >22.5° abaft the beam / sternlight-only cue.
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Power gives way in meeting/crossing, except when sail overtakes or in narrow-channel/impede cases.
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Opposite tacks: port tack gives way; same tack: windward gives way; the port-tack-unsure rule.
C. The Rule 18 hierarchy
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NUC > RAM > (CBD, International only) > fishing > sail > power > seaplane; overtaking trumps all.
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NUC = exceptional circumstance; RAM = nature of the work; "fishing" = gear restricting maneuverability, not sport trolling.
D. Sound signals (Rules 32–35, Inland)
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Short ≈1 s vs prolonged 4–6 s.
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Signals of INTENT with agreement by echo: 1 short = leave you on my port side; 2 = starboard; 3 = astern propulsion; 5+ = danger/doubt.
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International: 1 short = I AM altering to starboard (action, not intent) — hard-band delta.
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Leaving a dock or berth; the blind bend and its reply.
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Rule 35: power making way 1 prolonged ≤2 min; not making way 2; sail/fishing/NUC/RAM/towing 1+2; anchored rapid bell; aground bell pattern.
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Whistle required; the <12 m bell-alternative rule.
E. Lights & dayshapes (Rules 20–31)
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Sunset to sunrise plus restricted visibility.
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Sidelights 112.5° red-port/green-starboard; sternlight white 135°; masthead white 225°; all-round 360°.
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Power <12 m: all-round white plus sidelights option.
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Sidelights + sternlight, NO masthead light; red-over-green option; motorsailing = power plus cone apex down.
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Red+green+white ahead = head-on; single red = her port side; single green = her starboard; white alone = stern or anchored.
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Anchored all-round white/ball; NUC red-over-red/two balls; RAM red-white-red/ball-diamond-ball; CBD three reds (International).
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Trawling green-over-white; other fishing red-over-white; pilot white-over-red.
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Masthead pair (tow ≤200 m) or triple (>200 m); yellow tow light over the sternlight; diamond shape >200 m.
F. US Aids to Navigation (IALA-B)
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Red = even = nun; green = odd = can; numbers increase from seaward.
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Lighted buoys match side color; daymarks red triangle / green square.
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Safe-water (red-white stripes, pass either side); preferred-channel (top band governs); isolated danger (black-red, two balls).
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White-orange: diamond = danger; crossed diamond = exclusion; circle = controlled; square = information.
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Mooring buoy (white + blue band) is the only buoy to tie to; yellow = special marks.
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ICW yellow triangle/square reflectors — hard band.
G. Narrow channels & restricted visibility (Rules 9, 19)
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Keep to the starboard edge; <20 m/sail must not impede channel-bound vessels; no anchoring in a channel.
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NO stand-on vessel in fog; detect forward of the beam → avoid altering to port; hear a signal forward of the beam → minimum steerage way.
H. Part A — general provisions (Rules 1–3)
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Rules apply to ALL vessels on the applicable waters; Inland shoreward of the demarcation lines, International seaward.
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The COLREGS demarcation lines (33 CFR 80) are the physical boundary that switches which code you are under.
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Authorities may make special rules for roadsteads, harbors, rivers and inland waters; conformity "as closely as possible" for warships.
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Vessel traffic services established under Rule 1 and the duty to comply where they exist.
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"Vessel" = every description of watercraft used or capable of being used as a means of transportation on water — including a paddleboard.
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Power-driven = propelled by machinery, regardless of hull type or whether sails are also set.
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Sailing vessel = under sail AND propelling machinery, if fitted, NOT in use — the motorsailing trap.
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"Engaged in fishing" = nets, lines or trawls that RESTRICT maneuverability; trolling lines are explicitly excluded.
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Underway = not at anchor, not made fast to the shore, not aground — a drifting vessel with the engine off is underway.
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Making way = underway AND moving through the water; the distinction drives which fog signal you sound.
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Not under command: an exceptional circumstance leaves her unable to maneuver as required — a breakdown, not a choice.
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Restricted in ability to maneuver: the NATURE OF THE WORK restricts her — dredging, cable-laying, replenishment, launching aircraft.
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Constrained by draft (International only): draft relative to available depth and width, not merely a large ship.
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Fog, mist, falling snow, heavy rainstorms, sandstorms "and any other similar causes" — the trigger for Rule 19.
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Vessels are "in sight of one another" only when one can be observed VISUALLY from the other; radar contact alone is not in sight.
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Length and breadth mean LENGTH OVERALL and greatest breadth — the measurement every length threshold uses.
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Seaplane and wing-in-ground craft definitions and where each sits in the hierarchy.
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Rule 2(a): nothing exonerates from the consequences of neglect of ordinary practice of seamen or special circumstances.
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Rule 2(b): due regard to all dangers and special circumstances may REQUIRE a departure from the Rules to avoid immediate danger.
I. Part B section I — conduct in any condition of visibility (Rules 4–10)
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Rules 5–10 apply in ANY condition of visibility, fog included; Rules 11–18 only apply in sight of one another.
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"By sight and hearing as well as by all available means" — radar, AIS and a hand-held light are part of a proper lookout.
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The single-handed operator: why steering, phone use and passenger duties do not excuse a missed lookout.
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The second Rule 6 list for radar-equipped vessels: characteristics and limitations, scale in use, sea clutter, small-craft detection.
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Draft in relation to available depth of water as a safe-speed factor.
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Night background lighting from shore or your own deck lights degrades detection and lowers safe speed.
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Assumptions shall not be made on scanty information, ESPECIALLY scanty radar information.
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Proper use of radar: long-range scanning for early warning, plotting or equivalent systematic observation.
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The CBDR exception: risk may exist despite an appreciable bearing change with a very large vessel, a tow, or at close range.
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If there is ANY doubt, risk of collision shall be deemed to exist.
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Action must be large enough to be readily apparent to another vessel observing visually or by radar.
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A substantial alteration of COURSE alone may be most effective when there is sufficient sea room.
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Slacken speed, stop, or reverse — taking all way off is a legitimate collision-avoidance action.
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Action must result in passing at a safe distance, and its effectiveness is checked until FINALLY PAST AND CLEAR.
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A vessel required "not to impede" must take early action for sea room, and remains bound by Part B once risk develops.
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A vessel shall not cross a narrow channel if the crossing impedes a vessel that can navigate only within it.
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The narrow-channel overtaking protocol: the overtaker signals, the overtaken vessel must agree before the pass.
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Vessels engaged in fishing shall not impede any other vessel navigating within a narrow channel or fairway.
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Avoid anchoring in a narrow channel; a channel is not a parking spot.
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Traffic separation schemes: proceed in the lane's general direction of flow, keep clear of the separation zone.
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Join or leave at the termination of the lane where possible; joining from the side is done at as small an angle as practicable.
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Cross a lane on a heading as nearly as practicable at RIGHT ANGLES to the direction of flow.
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A vessel under 20 m or a sailing vessel shall not impede a power-driven vessel following a traffic lane.
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Inshore traffic zones: who may use them and the general prohibition on through traffic.
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Rule 16: the give-way vessel takes early and SUBSTANTIAL action to keep well clear.
J. Part B section III — restricted visibility procedure (Rule 19)
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Rule 19 applies to vessels NOT IN SIGHT of one another in or near an area of restricted visibility.
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Proceed at a safe speed adapted to the circumstances; a power-driven vessel keeps engines ready for immediate maneuver.
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When another vessel is detected by radar alone, determine whether close quarters or risk of collision is developing.
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Avoid an alteration to PORT for a vessel forward of the beam, other than for a vessel being overtaken.
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Avoid an alteration of course TOWARD a vessel abeam or abaft the beam.
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Hearing a fog signal apparently forward of the beam: reduce to bare steerageway and, if necessary, take all way off.
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"Navigate with extreme caution until danger of collision is over" — the standard once you are blind and close.
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There is no stand-on vessel in restricted visibility, so the Rule 13–18 privileges simply do not apply.
K. Lights and shapes — general provisions (Rules 20–22, Annex I)
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Rules 20–31 apply in ALL weathers; the lights are not optional on a clear night.
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No other light may be shown that can be mistaken for, impair the visibility of, or interfere with the prescribed lights.
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Shapes prescribed by these Rules are exhibited by DAY; the lights-vs-shapes pairing for each status.
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Masthead light: white, over the fore-and-aft centerline, 225° arc, 22.5° abaft the beam on each side.
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Sidelights: green to starboard, red to port, 112.5° each; a combined lantern is allowed under 20 m.
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Sternlight: white, 135° arc, placed as nearly as practicable at the stern.
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Towing light: YELLOW, with the same 135° characteristics as a sternlight.
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All-round light: unbroken over 360°; the building block for anchor, NUC, RAM and fishing displays.
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Flashing light: regular flashes at 120 or more per minute.
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Inland-only special flashing light: yellow, 50–70 flashes per minute, at the head of a pushed tow.
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Required visibility ranges step down with vessel length (6/5/3/2-mile masthead bands); a small boat's lights are legally dimmer.
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Annex I vertical positioning and spacing: how far apart stacked lights must be so the pattern is readable at range.
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Sidelight inboard screens exist so a red is never visible from starboard — the reason aspect reading works.
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Annex I luminous intensity and the relationship between intensity and required range.
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Ball, cone, cylinder and diamond dimensions and their vertical spacing.
L. Lights and shapes by vessel status (Rules 23–31)
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Masthead light forward, a second masthead abaft and higher if 50 m or more, sidelights, sternlight.
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Power-driven under 12 m: an all-round white plus sidelights is the alternative display.
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An air-cushion vessel in non-displacement mode adds an all-round FLASHING YELLOW.
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WIG craft taking off, landing or flying near the surface add a high-intensity all-round flashing RED.
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Two masthead lights in a vertical line (three if the tow exceeds 200 m), sidelights, sternlight, towing light above it.
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A diamond shape is shown by the towing vessel and the tow when the tow exceeds 200 m.
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Pushing ahead or towing alongside: two masthead lights in a vertical line and no towing light.
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Inland: a tug and a rigidly connected pushed unit are lit as ONE power-driven vessel.
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The vessel or object being towed shows sidelights and a sternlight — a dark barge astern is a hazard, not a legal display.
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Partly submerged and inconspicuous tows: all-round whites at the ends and a diamond, because the object itself is nearly invisible.
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A sailing vessel may combine sidelights and sternlight in one tricolor at the masthead — but only under 20 m and never with a masthead light.
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A sailing vessel under 7 m may show a white lantern or torch in time to prevent collision if the prescribed lights are impractical.
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A vessel under oars may show sailing-vessel lights or exhibit an electric torch in time to prevent collision.
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A vessel under sail AND power shows a cone apex downward forward; Inland exempts vessels under 12 m.
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Trawling: all-round GREEN over WHITE, plus a masthead light abaft and higher when making way.
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Fishing other than trawling: all-round RED over WHITE, and a white light or cone toward outlying gear beyond 150 m.
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Two cones apex together in a vertical line; a vessel under 20 m may substitute a basket.
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A fishing vessel NOT engaged in fishing shows only the lights for her length — the trap of the parked trawler.
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Not under command: two all-round REDS in a vertical line / two balls; sidelights and sternlight only when making way.
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Restricted in ability to maneuver: RED-WHITE-RED all-round / ball-diamond-ball, plus the normal underway lights when making way.
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A RAM vessel with an obstruction shows two reds/two balls on the foul side and two greens/two diamonds on the side to pass.
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A towing operation that severely restricts the tug's ability to deviate shows the RAM display in addition to the towing lights.
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A small vessel engaged in diving shows a rigid replica of flag "A" at least 1 m high; the recreational red-and-white diver-down flag is state law, not a Rule 27 signal.
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Mine clearance: three all-round GREENS / three balls, and the 1,000 m standoff obligation.
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Constrained by draft: three all-round REDS in a vertical line or a CYLINDER — International only.
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Pilot vessel on duty: all-round WHITE over RED, plus sidelights and sternlight underway or anchor lights at anchor.
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At anchor: an all-round white forward and a second lower aft (100 m or more), or one all-round white under 50 m; a BALL by day.
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Vessels 100 m or more must, and others may, use available working lights to illuminate the decks at anchor.
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Aground: anchor lights plus two all-round REDS in a vertical line; three BALLS by day.
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Under 7 m at anchor outside a channel or anchorage, and under 12 m aground, are exempt from parts of Rule 30.
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A seaplane or WIG craft unable to comply exhibits lights and shapes as close as possible in characteristics and position.
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Annex II additional signals for fishing vessels working in close proximity (shooting, hauling, net fast on an obstruction).
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Inland: the flashing blue light identifying a law-enforcement vessel, and the alternately flashing red-and-yellow for public-safety vessels.
M. Sound and light signals (Rules 32–37, Annexes III–IV)
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Rule 32 defines "whistle", "short blast" (~1 s) and "prolonged blast" (4–6 s) — every other signal is built from these.
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Sound-signal equipment scales with length: whistle and bell at 12 m and above, gong as well at 100 m and above.
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Maneuvering signals may be supplemented by an all-round white (Inland: white or yellow) light synchronized with the blasts.
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Inland maneuvering signals are proposals: the other vessel echoes to agree, or sounds the danger signal to refuse.
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International Rule 34 signals announce action already being taken, so there is no agreement echo — the classic Inland/International delta.
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Narrow-channel overtaking: two prolonged + one short (pass on your starboard) or + two short (your port), answered before the pass.
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Five or more short and rapid blasts is the doubt/danger signal, with an optional matching light signal.
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One prolonged blast approaching a bend or obstruction, and the answering prolonged blast from a vessel within hearing.
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Inland: one prolonged blast when leaving a dock or berth.
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Fog signals are sounded at intervals of NOT MORE THAN 2 minutes — the interval is part of the signal.
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Power-driven making way through the water: ONE prolonged blast.
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Power-driven underway but STOPPED and making no way: TWO prolonged blasts about 2 seconds apart.
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NUC, RAM, CBD, sailing, fishing and towing vessels all sound one prolonged + two short — the shared pattern and why it is ambiguous.
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The last manned vessel of a tow sounds one prolonged + THREE short, immediately after the towing vessel.
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At anchor: rapid ringing of the bell for about 5 seconds each 2 minutes minimum.
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100 m or more at anchor: the bell forward AND a gong aft, so the listener hears the vessel's length.
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The optional one short + one prolonged + one short to warn an approaching vessel of your position at anchor.
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Aground: three distinct strokes before and after the rapid bell ringing.
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Under 12 m need not sound the prescribed signals, but MUST make some efficient sound signal at least every 2 minutes.
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A pilot vessel on duty may add four short blasts as an identity signal.
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Signals to attract attention must not be mistakable for a Rule signal; a searchlight must not embarrass another vessel.
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Rule 37 points to Annex IV: any of the listed distress signals, used together or separately, means distress and need of assistance.
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The Annex IV list: gun at intervals, continuous fog apparatus, rockets, MAYDAY, NC flags, square flag and ball, flames, red flares, orange smoke, slow arm raising, EPIRB, dye.
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Using a distress signal when not in distress, or any signal that could be confused with one, is prohibited.
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Annex III whistle fundamental frequency, sound-pressure level and audibility range scale with vessel length.
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Bell and gong material, diameter and hammer requirements; why a small boat's horn substitute is not equivalent.
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33 CFR 26: VHF channel 13 (or 67 in designated areas) bridge-to-bridge radiotelephone, and radio agreement in lieu of whistle signals on Inland waters.
N. The US Aids to Navigation System in depth
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The US is IALA Region B, which is why RED is on the starboard hand returning — the opposite of Region A.
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"Returning from seaward" is a defined convention, not a compass heading; how it runs along coasts and up rivers.
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Unlighted buoys carry the meaning in SHAPE (nun vs can); lighted buoys carry it in color, because shape is lost at night.
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Numbers increase from seaward; even on red, odd on green; letters on non-lateral marks.
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Flashing, quick flashing, occulting, isophase, composite group flashing and Morse "A" — what each rhythm signals.
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Red and green lights repeat the lateral color; white lights appear on safe-water, isolated-danger and special marks.
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Junction marks: the TOP band gives the preferred channel; composite group flashing (2+1) rhythm.
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Red and white vertical stripes, Morse "A" white light, spherical or with a red spherical topmark — mid-channel, pass either side.
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Black with a red band, two black spherical topmarks, group flashing (2) white — moored ON or near the danger.
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Yellow marks for anchorages, dredging, fishnet areas and traffic separation — informational, not lateral.
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Fixed daybeacons carry dayboards on a structure; floating buoys can drag, sink or go off station.
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A buoy's charted position is approximate; never navigate so close that a shifted buoy becomes a grounding.
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Range marks in line define a channel centerline; directional lights use white, red and green sectors for the same job.
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A lighthouse's red sector marks foul ground; the color you see tells you which side of the safe arc you are on.
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Radar beacons and reflectors extend an aid's usefulness to a radar screen.
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The USCG Light List and the Local Notice to Mariners are the correction channel; an uncorrected chart is out of date.
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Reading buoy, light and depth symbols on a NOAA chart; the light characteristic abbreviation format.
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Where the ICW coincides with another waterway, dual-purpose marks carry BOTH sets of markings; the yellow triangle/square governs the ICW.
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Western Rivers use mile boards, passing and crossing daymarks, and lights without numbers.
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The Uniform State Waterway Marking System on state waters (33 CFR 66) and how it relates to the federal system.
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Private aids to navigation require Coast Guard authorization; an unauthorized mark is a hazard.
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Damaging, moving or mooring to a federal aid is prohibited; discrepancies are reported to the Coast Guard.
O. Traffic management, bridges and regulated areas
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VTS user requirements: designated frequency guard, sailing plan and position reports where required.
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VTS may issue measures or directions, but the master remains responsible for the safe navigation of the vessel.
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Vessel movement reporting systems and mandatory reporting points on congested waterways.
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RNAs, safety zones and security zones: what each restricts and how they are published.
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33 CFR 100 regattas and marine parades: temporary restrictions and patrol-vessel instructions.
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Designated anchorage grounds and the places anchoring is prohibited.
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Requesting a drawbridge opening: the sound and radio signal, and the acknowledging or "cannot open" reply.
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Bridge lighting and clearance gauges: reading the channel span and vertical clearance at the actual water level.
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Lock signals and lockage priority; small craft yield to commercial traffic.
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Blind zones, stopping distance measured in ship lengths, and the suction and bank effects that pull a small boat in.
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Judging a towline in the dark; never passing between a tug and its tow.
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Operating around ferries on fixed routes, dive-flag standoffs and working fishing fleets.
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