Which of the following is crucial to declare in a float plan?

Declaring the estimated time of arrival (ETA) in a float plan is crucial because it provides essential information to others about when to expect your return. This helps in ensuring safety, as the ETA assists search and rescue operations in the event of an emergency. If a vessel does not return as scheduled, the authorities and loved ones will have a timeline to initiate search efforts. Establishing a clear ETA contributes to accountability and enhances overall safety during a boating trip.

Uncharted soundings and pictures of crew, while potentially useful in certain scenarios, do not provide the key safety information that an ETA does. The vessel’s maximum speed, although it may give a rough idea of travel time, doesn’t communicate a specific timeframe for return, which is the critical aspect of a well-prepared float plan. Thus, the estimated time of arrival is the most important piece of information for those who need to track the vessel's safety.