What is required on vessels that are more than 16 feet but less than 40 feet in length on Missouri state waters?

Vessels that are more than 16 feet but less than 40 feet in length when operating on Missouri state waters are required to carry a whistle or horn. This requirement is in place to ensure that vessels can signal other boats and communicate effectively in various situations, particularly in instances where visibility may be limited or when navigating crowded waterways. Having an appropriate sound signaling device enhances safety on the water by allowing boaters to alert others of their presence and intentions.

The other options, while they may serve useful purposes in certain scenarios, are not mandated for this specific size category of vessels in Missouri. A bell is typically required for larger vessels or specific situations, a flag may denote specific conditions but is not a standard requirement, and while a compass is useful for navigation, it is not a legal requirement for vessels in this size range. Therefore, the emphasis on the whistle or horn is crucial for safety and compliance with Missouri boating regulations.