Final answer:
A whistle or horn is required aboard a 22-foot powerboat according to Navigation Rules.
Explanation:
In accordance with the Navigation Rules, a whistle or horn must be aboard a 22-foot powerboat. This device is crucial for emitting sound signals to alert other vessels of the powerboat's presence or intentions, enhancing safety on the water. While a searchlight, GPS, Loran-C receiver, and VHF radio can be beneficial for navigation and communication, a whistle or horn is a legal requirement under the Navigation Rules.
Learn more about Navigation Rules and safety equipment on a powerboat here:
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