What does the term WIG craft refer to in maritime terminology?

The term WIG craft stands for Wing-In-Ground craft. This designates a type of vehicle that is capable of flying or gliding at very low altitudes, typically just above the water's surface. WIG craft utilize the ground effect, which is the increase in lift and decrease in drag that occurs when an aircraft flies close to a surface. This allows them to travel efficiently over water with a unique aerodynamic profile that makes them different from traditional aircraft.

Understanding this term is significant in maritime contexts as WIG craft are often used for various applications, including transport and surveillance, and they can have implications for navigation and collision avoidance due to their speed and low flight nature. In contrast, the other options presented do not accurately describe the nature of these craft and hence are not the correct definition.