Boating Coach US
Aids to navigationQuestion 256 of 352

Which light rhythm does a safe water mark show?

  1. White, with a short and a long flash (Morse A)
  2. Red, two flashes then one
  3. White, two flashes in a group
  4. Yellow, slow flashing
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Correct answer: White, with a short and a long flash (Morse A)

The Morse A rhythm is a short flash and then a long flash. It is white.

Source: US Code of Federal Regulations (eCFR), 33 CFR Part 62: United States Aids to Navigation System, § 62.45 Light characteristics

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Questions last reviewed: 18 October 2026