OUPV Navigation Rules Practice Test

The sound signal for a vessel that is underway and unsure of another vessel’s intentions is one prolonged blast. This signal is used to communicate uncertainty and to alert other vessels to the situation. It serves as a way to indicate to nearby vessels that there is some confusion regarding movements or intentions, allowing them to be more cautious or clarify their own intentions.

In the context of navigation rules, using a prolonged blast effectively communicates the vessel's status or intentions beyond the immediate visibility range, which is essential for maintaining safety in busy waters. This signal helps prevent misunderstandings that could lead to close quarters situations or collisions.

Other sound signals have different specific meanings: one short blast indicates a turn to starboard, while two short blasts signify a turn to port. Two prolonged blasts typically represent a vessel operating in restricted visibility, so it is crucial to understand that each sound has its distinct purpose in maritime communication.