Which situation requires you to furnish a notice of marine casualty to the Coast Guard?

Correct Answer: Option C — Your vessel is at anchor and grounds at low tide with no apparent damage.

46 CFR § 4.05-1 requires reporting for any grounding, regardless of whether damage is immediately apparent. Groundings are considered significant marine casualties because they can cause hidden structural damage to the hull or propulsion systems, necessitating a formal assessment and report to the Coast Guard to ensure vessel seaworthiness.