Final answer:
In Alabama, an 18 foot powerboat must be equipped with a sound device such as a horn or whistle audible for at least one-half mile to meet safety regulations.
Step-by-step explanation:
When boating on Alabama waters on an 18 foot powerboat, there are specific safety requirements that need to be met, including having certain sound-devices on board. The Alabama Marine Patrol Division mandates that all vessels, including powerboats, must have a means of making an efficient sound signal. This typically means that powerboats like the one described should be equipped with a horn or whistle that is audible for at least one-half mile. These sound signals are essential for notifying other boaters of your presence in foggy conditions or to signal distress if necessary.