According to the Navigation Rules, a rapidly ringing bell every minute signals what?

A rapidly ringing bell every minute is a specific signal used by boats that are anchored in foggy conditions. This practice aligns with the Navigation Rules designed to enhance safety on the water by ensuring that vessels can communicate their presence effectively in low visibility situations. The sound of the bell serves to alert other nearby vessels of the anchored boat's position, thus preventing possible collisions and promoting safe navigation. Understanding the function of sound signals like this is vital for boaters, especially when navigating through fog, where visibility may be significantly compromised.