A sailing vessel with the wind abaft the beam is navigating in fog. She should sound _____________.

When a sailing vessel has the wind abaft the beam while navigating in fog, it is required to sound one prolonged blast followed by two short blasts. This combination of sounds serves as a communication signal to warn other vessels of its presence and intentions while operating in limited visibility conditions.

The one prolonged blast indicates the vessel is under way and maintaining its course, while the two short blasts communicate that the vessel is sailing, distinguishing it from other types of vessels that may use different sound signals. This is particularly important in foggy conditions, where visibility is significantly reduced, and sound signals become a crucial means of preventing collisions.

This signaling protocol is established in the International Regulations for Preventing Collisions at Sea (COLREGs) and is essential for the safety of all vessels operating in close proximity under such conditions. Other sound signals, while they may refer to different situations or vessel statuses, do not convey the specific message that one prolonged and two short blasts do in the context of a sailing vessel with the wind abaft the beam in fog.