08/19/2026
🚨 NUC AT 0200: CAN YOU READ THE LIGHTS?
Every OOW knows RED–RED, but the real test comes when the vessel is closing fast and you must interpret the situation correctly.
⚓ THE SCENARIO
• 🚢 300 m container ship suffers steering failure.
• 🕑 Time: 0200, coastal traffic nearby.
• ❌ Vessel cannot manoeuvre as required.
• → She is potentially Not Under Command (NUC).
• → NUC is not simply “engine stopped.”
🔴 WHAT SHOULD YOU SEE?
• 🌙 Night: two all-round red lights vertically.
• ☀️ Day: two black balls vertically.
• 🚢 If making way: sidelights + sternlight also displayed.
• ❌ RED–WHITE–RED = RAM, not NUC.
🧭 THE WATCHKEEPER'S TRAP
• → NUC signals communicate the vessel's condition.
• ❌ They do not mean “I have priority.”
• → Other vessels still apply the COLREGs.
• → Assess CPA, TCPA, traffic and developing risk.
🎯 REMEMBER
NUC = RED over RED / BALL over BALL.
Confusing NUC with RAM can turn an exam mistake into a collision-risk mistake.
👇 OOWs: have you ever encountered a genuine NUC vessel? What failed?
