Rule 5

Look-out

Any visibility

Keep a proper look-out by sight and hearing — and every other available means — at all times.

In plain language

Someone must always be watching and listening — the rule names sight and hearing specifically, so radar, AIS, and alarms can add to a look-out but never replace it. The goal is a full appraisal of the situation: what is around you, what it is doing, and whether risk of collision exists. Most collisions trace back to a failure of this one short rule.

Takeaway

Eyes and ears, always — electronics assist the look-out, they never replace it.