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RulesRule 4
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Part B-IBasic

Rule 4: Section I application

Section I is always active, regardless of visibility.

Detailed Explanation

Rules 4 to 10 apply in any visibility condition. Even in dense fog, these baseline conduct rules still apply, with Rule 19 adding specific restricted-visibility actions.

Key Points

  • Rules 4-10 apply in ALL visibility conditions
  • Fog adds Rule 19 but never suspends Section I
  • Section I is the always-on baseline of conduct

Examples

  • In dense fog you observe a radar target 6 miles ahead. Rules 5-10 still apply in full; you begin plotting immediately and post an extra lookout.
  • A container ship transits a TSS in clear weather. Section I (Rules 4-10) governs her conduct; should visibility drop, Rule 19 adds additional obligations on top.

Common Mistakes

  • Believing Rules 4-10 only apply in good visibility and can be suspended in fog.
  • Forgetting that Section I rules remain fully active even when Rule 19 also applies in restricted visibility.

Related Rules

R5Look-outR11Section II applicati…R19Conduct in restricte…
Mini Quiz

Rule 4: which statement is most correct in practice?

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