When a vessel-related accident occurs on the navigable waters of the United States, the investigation machinery starts up almost immediately. The operator, owner, or person in charge of a vessel involved in such a casualty is obliged to give the soonest practicable notification, often followed by a written report, to the local Coast Guard Sector or office. This begins a process in which livelihoods, liberty, and civil liability might all be at stake. Careful thought is required when the Coast Guard investigating officer calls to request an interview.