COLREG / ARPA / AIS Bridge Rule 24(a) Rule 24(a)(i) 🔒 Course / Premium

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...

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Scenario briefing

NIGHT. A towing vessel shows: THREE masthead lights in a vertical line on the forward mast; sidelights; sternlight; YELLOW towing light above the sternlight. What does the THREE-vertical masthead configuration tell you?

Applicable COLREG rule(s)

Rule 24(a) — referenced in this scenario. Practising this scenario reinforces correct application under realistic time pressure.

Rule 24(a)(i) — referenced in this scenario. Practising this scenario reinforces correct application under realistic time pressure.

📸 Night recognition — 8 aspects

The same vessel rendered every 45° of aspect — bow, starboard bow, beam, quarter, stern, port quarter, beam, bow. Use this strip to learn how the lights present from each approach angle. Click any image to view full size.

Towing vessel — tow over 200 m viewed head-on (bow aspect) — COLREG Rule 24(a)(i) night-recognition diagram — Bow

Towing vessel — tow over 200 m viewed from her starboard bow — COLREG Rule 24(a)(i) night-recognition diagram — STBD bow

Towing vessel — tow over 200 m viewed from her starboard beam — COLREG Rule 24(a)(i) night-recognition diagram — STBD beam

Towing vessel — tow over 200 m viewed from her starboard quarter — COLREG Rule 24(a)(i) night-recognition diagram — STBD qtr

Towing vessel — tow over 200 m viewed dead astern (stern aspect) — COLREG Rule 24(a)(i) night-recognition diagram — Stern

Towing vessel — tow over 200 m viewed from her port quarter — COLREG Rule 24(a)(i) night-recognition diagram — Port qtr

Towing vessel — tow over 200 m viewed from her port beam — COLREG Rule 24(a)(i) night-recognition diagram — Port beam

Towing vessel — tow over 200 m viewed from her port bow — COLREG Rule 24(a)(i) night-recognition diagram — Port bow

Why it matters

COLREG knowledge is the foundation of safe ship handling. Most maritime collisions happen because watchkeepers either misidentified the situation, applied the wrong rule, or acted too late. This scenario lets you train pattern recognition + correct response under time pressure — the exact skill the rules are designed to support. RYA, Yachtmaster, STCW and most national exams expect you to apply COLREGs reflexively, not just recite them.

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