All COLREG & VHF Practice Scenarios

69 browser-based maritime training drills covering the COLREG 1972 collision-avoidance rules and VHF Short Range Certificate radio procedure. Ideal for RYA, Yachtmaster, STCW prep, deck-officer cadets and skippers refreshing certification.

📜 54 COLREG 📡 15 VHF SRC ✓ 10 free demos 🌐 No install

ARPA · AIS · COLREG Bridge Simulator 54 scenarios

Bridge-style ARPA radar with AIS overlay. Practise CPA/TCPA assessment, give-way / stand-on action, restricted visibility, narrow channels, TSS, sound signals and night-light recognition.

FUNDAMENTALS — RULES 2, 5, 6, 7, 8

EXPLORE

Familiarisation — Free Mode

Busy-traffic familiarisation on an INTEGRATED BRIDGE display AIS targets overlaid on a radar-style PPI. This mirrors a modern ECDIS/radar where the two data …

RULE 7

CPA/TCPA Recognition (Rule 7)

A single target is inbound. Under Rule 7 you must use all available means (radar, AIS) to determine if risk of collision exists. Observe the target for at le…

RULE 6

Safe Speed in Fog (Rule 6)

Visibility is under 1 NM and AIS shows dense traffic. Rule 6 requires every vessel to proceed at a SAFE SPEED appropriate to prevailing conditions. Rule 19(b…

RULE 8

Action to Avoid Collision (Rule 8)

A target is inbound on a fine starboard bow, developing risk of collision. Apply Rule 8: (a) AMPLE TIME act EARLY, while the other vessel still has plenty of…

RULE 5

Look-Out Scan & Identify (Rule 5)

Conduct a proper look-out by sight and hearing. Identify all targets in the vicinity by name and bearing. Rule 5 requires every vessel to maintain a proper l…

DEPARTURE FROM THE RULES — RULE 2

RULE 2(A)

Rule 2 — Departure to Avoid Immediate Danger

DILEMMA: Clear visibility. You are the STAND-ON vessel in a crossing situation a power-driven give-way vessel is on your PORT side and has failed to act. Rul…

RULE 23(A)

Rule 23 — Power-Driven Vessel Underway Lights

NIGHT. You observe the following lights approaching from ahead: two MASTHEAD lights in a vertical line (fore lower, after higher); RED sidelight on the left,…

RULE 24(A)

Rule 24 — Towing Vessel Lights

NIGHT. You see an approaching vessel showing: TWO masthead lights in a vertical line (forward mast); red & green sidelights; white sternlight + a YELLOW "tow…

RULE 25(A)

Rule 25 — Sailing Vessel Underway Lights

NIGHT. You see an approaching vessel showing: red & green sidelights; white sternlight (she is heading generally toward you and slightly past); NO masthead l…

RULE 26(B)

Rule 26 — Fishing Vessel Lights

NIGHT. A vessel in your vicinity shows at or near her masthead two all-round lights: GREEN OVER WHITE, in a vertical line. She is making way. What is she doing?

RULE 27(A)

Rule 27 — NUC / RAM Lights

NIGHT. You observe a vessel showing at her masthead THREE all-round lights in a vertical line: RED WHITE RED. She is making way through the water and also sh…

RULE 28

Rule 28 — CBD Vessel Lights

NIGHT. A vessel shows THREE all-round RED lights in a vertical line in addition to the lights required for a power-driven vessel. What is she?

RULE 29(A)

Rule 29 — Pilot Vessel Lights

NIGHT. You observe a vessel showing at or near her masthead two all-round lights in a vertical line: WHITE OVER RED. She also shows sidelights and a sternlig…

RULE 23(D)

Rule 23(d) — PDV < 7 m AND < 7 kn

NIGHT. A very small power-driven vessel is observed. Her length is less than 7 m and her maximum speed does not exceed 7 kn. She exhibits ONE all-round WHITE…

RULE 27(D)

Rule 27(d) — Dredger / Underwater Ops

NIGHT. A vessel is engaged in dredging or underwater operations. She shows: the three RAM lights vertically (RED-WHITE-RED); normal masthead/sidelights/stern…

RULE 24(A)

Rule 24(a)(i) — Tow > 200 m

NIGHT. A towing vessel shows: THREE masthead lights in a vertical line on the forward mast; sidelights; sternlight; YELLOW towing light above the sternlight.…

RULE 23(B)

Rule 23(c) — WIG Craft (Wing-in-Ground)

NIGHT. A sleek low-flying craft with stubby wings skims just above the surface. She shows normal PDV lights (masthead + sidelights + sternlight) AND an addit…

RULE 23(B)

Rule 23(b) — Air-Cushion Vessel (Hovercraft)

NIGHT. A wide low craft skims across the surface on an inflated skirt, leaving no wake. She shows normal PDV lights (masthead + sidelights + sternlight) AND …

RULE 27(A)(I)

Rule 27(a) — NUC NOT Making Way

NIGHT. A vessel shows TWO all-round RED lights in a vertical line where they can best be seen, and NOTHING ELSE no sidelights, no sternlight, no masthead lig…

RULE 27(B)(I)

Rule 27(b) — RAM NOT Making Way / At Anchor

NIGHT. A vessel shows three all-round lights in a vertical line where they can best be seen: RED-WHITE-RED. She shows NO masthead light, NO sidelights, and N…

RULE 26(C)(I)

Rule 26(c) — Fishing (Nets / Lines, Non-Trawling)

NIGHT. A vessel at or near her masthead shows two all-round lights in a vertical line: RED OVER WHITE. She is making way, no trawl gear, working with set NET…

RULE 27(F)

Rule 27(f) — Mineclearance Vessel

NIGHT. A warship displays normal PDV lights (masthead + sidelights + sternlight) AND in addition THREE all-round GREEN lights one at the foremast head and on…

RULE 25(B)

Rule 25(b) - Sailing Tricolour < 20 m

NIGHT. A sailing vessel less than 20 m in length is approaching. She shows, at or near the top of the mast where it can best be seen, a SINGLE lantern combin…

RULE 25(E)

Rule 25(e) - Sailing AND Motoring

Daylight + NIGHT consideration. A vessel proceeds under SAIL and at the same time is being propelled by MACHINERY. What signal identifies this dual propulsio…

RULE 26(C)(II)

Rule 26(c)(ii) - Fishing with Outlying Gear > 150 m

NIGHT. A vessel engaged in fishing (not trawling) shows RED OVER WHITE all-round at or near the masthead AND, in addition, a WHITE all-round light offset 120…

NARROW CHANNELS — RULE 9

RULE 9(A)

Narrow Channel — Keep Starboard (Rule 9(a))

You are transiting a narrow channel marked by the two dashed yellow lines on the PPI. Rule 9(a): keep as near to the outer limit of the channel on your STARB…

RULE 9(E)

Narrow Channel Overtaking (Rule 9(e))

You are in a narrow channel overtaking a slower vessel. Rule 9(e)(i): overtaking is only permissible when the overtaken vessel has to take action to allow sa…

TRAFFIC SEPARATION SCHEMES — RULE 10

RULE 10(C)

TSS — Crossing at Right Angles (Rule 10(c))

You must cross a Traffic Separation Scheme whose lanes run NS (shown on the PPI). Rule 10(c): a vessel crossing traffic lanes shall do so on a heading as NEA…

RULE 10(B)(II)

TSS — Joining at a Shallow Angle (Rule 10(b)(ii))

You are joining the northbound TSS lane (right lane). Rule 10(b)(ii): a vessel joining a lane shall do so at as SMALL AN ANGLE to the general direction of tr…

SAILING VESSELS — RULE 12

RULE 12(A)

Rule 12 — Sailing vs Sailing

Clear visibility. You are under SAIL with the wind on your PORT side (port tack). A SAILING vessel ahead has the wind on her STARBOARD side (starboard tack).…

VESSELS IN SIGHT — RULES 13–17

RULE 13

Overtaking (Rule 13)

You are overtaking a slower vessel (you come from more than 22.5° abaft her beam). Rule 13 applies even in restricted visibility you must keep out of the way…

RULE 13

Being Overtaken (Rule 13 / 17)

A faster vessel is overtaking you from astern. The overtaking vessel must keep out of the way. Under Rule 17 you generally keep your course and speed unless …

RULE 14

Head-On Situation (Rule 14)

Clear visibility. A power-driven vessel approaches you on a reciprocal course, nearly right ahead. Rule 14(a): each shall alter course to STARBOARD so that e…

RULE 15

Crossing — You Are Give-Way (Rule 15 / 16)

Clear visibility. A power-driven vessel is on your STARBOARD side, crossing from right to left. Rule 15: you shall keep out of the way and, if circumstances …

RULE 17(A)(I)

Crossing — You Are Stand-On (Rule 17(a)(i))

A power-driven vessel is on your PORT side, crossing right to left. You are the stand-on vessel. Rule 17(a)(i): keep your course and speed. The other vessel …

RULE 17(A)(II)

Stand-On — Last-Moment Action (Rule 17(b)(c))

Crossing situation target on your PORT quarter/beam is the give-way vessel but is NOT altering. Rule 17(a)(ii): as stand-on you may take action when it becom…

RESPONSIBILITIES BETWEEN VESSELS — RULE 18

RULE 18(A)(IV)

Power-Driven Gives Way to Sailing Vessel (Rule 18(a)(iv))

AIS identifies the target as a sailing vessel (badge "S"). You are a power-driven vessel Rule 18(a)(iv): a power-driven vessel under way shall keep out of th…

RULE 18(A)(III)

Power-Driven Gives Way to Fishing Vessel (Rule 18(a)(iii))

Target is identified by AIS as a vessel ENGAGED IN FISHING (badge "F"). Rule 18(a)(iii): a power-driven vessel under way shall keep out of the way of a vesse…

RULE 18(A)(II)

Power-Driven Gives Way to Vessel RAM (Rule 18(a)(ii))

The AIS target reports "Restricted Ability to Manoeuvre" (RAM) e.g. a cable-layer or dredger (badge "R"). Rule 18(a)(ii): a power-driven vessel shall keep ou…

RULE 18(D)

Avoid Impeding Vessel Constrained by Draught (Rule 18(d))

Chart overlay shows a narrow DREDGED APPROACH CHANNEL (blue, ~0.8 NM wide, dredged to 15 m) with wider water around it (stippled, 57 m). Your draught is 3.0 …

RESTRICTED VISIBILITY — RULE 19

RULE 19(D)

RV — Target Right Ahead (Rule 19(d))

Fog. Visibility under 0.5 NM. A target has been detected by radar right ahead, closing on reciprocal course. Take action in ample time. Rule 19(d)(i) prohibi…

RULE 19(D)(I)

RV — Target on Port Bow (Rule 19(d)(i))

Fog. A target is detected 030° on the port bow (forward of the beam), closing with significant risk of collision. Rule 19(d)(i): avoid an alteration of cours…

RULE 19(D)(I)

RV — Target on Starboard Bow (Rule 19(d)(i))

Fog. Target detected on your starboard bow, forward of the beam. Rule 19(d)(i) forbids alteration to port. Altering toward the target (i.e. to starboard when…

RULE 19(D)(II)

RV — Target Abeam Starboard (Rule 19(d)(ii))

A target is detected abeam on your starboard side (relative bearing ~090°). Rule 19(d)(ii): AVOID alteration of course TOWARD a vessel abeam or abaft the bea…

RULE 19(D)(II)

RV — Target Abaft Port Beam (Rule 19(d)(ii))

Target detected abaft your port beam, slowly closing (relative bearing ~160° port / ~200° true from your heading). AIS identifies her as a SAILING vessel (ba…

RULE 19(E)

RV — Close Quarters Unavoidable (Rule 19(e))

You hear a fog signal forward of the beam. The target is detected very close (under 2 NM) on a steady bearing. Rule 19(e): when close-quarters cannot be avoi…

RULE 19

RV — Multi-Target Encounter (Rule 19)

RESTRICTED VISIBILITY (fog, heavy rain, snow). You cannot see either vessel visually you only have radar/AIS. Rule 19 governs: there is NO stand-on/give-way,…

SOUND SIGNALS — RULES 34–35

RULE 34(A)

Rule 34(a) — Whistle Manoeuvring Signals

POWER-DRIVEN vessels in sight of one another use whistle signals to indicate helm actions (Rule 34(a)): (1 short, 1s) = "I am altering my course to STARBOARD…

RULE 34(D)

Rule 34(d) — Doubt / Disagreement Signal

POWER-DRIVEN vessels in sight of one another, when in DOUBT whether sufficient action is being taken by the other to avoid collision, shall indicate such dou…

RULE 35(A)

Rule 35(a) — PDV Underway in Fog

FOG. Visibility 0.3 NM. You are a power-driven vessel MAKING WAY through the water. Rule 35 requires you to sound specific signals at intervals of NOT MORE t…

RULE 35(C)

Rule 35(c) — NUC / RAM / Sailing / Fishing Fog Signal

FOG. You hear, at intervals of not more than 2 minutes, one prolonged blast followed by two short blasts: . Under Rule 35(c), which of the following vessels …

LIGHTS & SHAPES — RULES 23–31

RULE 30(A)

VHF SRC Radio Simulator 15 scenarios

Realistic Icom-style VHF radio panel. Practise voice Mayday, DSC distress alerts, Mayday Relay, Pan-Pan urgency, Sécurité safety and routine calls — exactly what your VHF SRC examiner will check.

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VHF SRC practice scenario.