Danger, Safe Water, Special, and Emergency Wreck Marks

• Distinguish isolated-danger, safe-water, special and emergency-wreck marks by the navigation question each family answers before using colour, topmark or light detail.
• Explain why navigable water around both families does not make isolated danger and safe water interchangeable, then state the different route checks each requires.
• Combine the isolated-danger body's horizontal black and red bands, two-sphere topmark, white group-flashing-two light and charted position without inventing a fixed body shape or passing distance.

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