How often should an anchored vessel's sound signal be repeated?

Answer: A — Every one minute

The frequency of sound signals from an anchored vessel is designed to ensure that other vessels in the vicinity can detect its presence, particularly under conditions of limited visibility. According to the COLREGs, specifically Rule 35, a vessel at anchor must sound a signal, which is a short blast, at intervals of every one minute. This practice helps to maintain awareness of the anchored vessel's position and informs nearby mariners that it is indeed anchored and not under way. The choice of one minute as the interval strikes a balance between signaling its presence and avoiding excessive noise in the environment. Thus, following this specific timing is crucial for maritime safety and navigation.