The semi-displacement hull is a combination of characteristics of the ______ hull and the ______ hull. Many ______ boats are this type.

The semi-displacement hull is a combination of characteristics of the ______ hull and the ______ hull. Many ______ boats are this type.

• A. Displacement hull and Planing hull; Many Coast Guard boats are this type.
• B. Displacement hull and Deep-V hull; Many fishing boats are this type.
• C. Planing hull and Semi-displacement hull; Many sailing boats are this type.
• D. Semi-displacement hull and Displacement hull; Many racing boats are this type.

Answer: (A)

A semi-displacement hull blends the efficiency and seakeeping of a displacement hull with the speed potential of a planing hull. At lower speeds it behaves like a displacement hull, giving stable handling and good fuel economy for long patrols. As speed increases, the hull starts to lift and ride more on top of the water, reducing resistance and allowing higher speeds than a pure displacement hull, though it doesn’t reach the full sprint of a pure planing hull. This gives a practical balance between range, stability, and faster response when needed. Coast Guard boats use this type because they need to cruise efficiently over long distances while still being able to accelerate to respond quickly to incidents, especially in rough seas where stability and range matter. Other hull types either sacrifice efficiency at speed (pure planing) or speed at efficiency (pure displacement), and deep-V designs are typically associated with planing configurations rather than the mixed characteristics described here.

A semi-displacement hull blends the efficiency and seakeeping of a displacement hull with the speed potential of a planing hull. At lower speeds it behaves like a displacement hull, giving stable handling and good fuel economy for long patrols. As speed increases, the hull starts to lift and ride more on top of the water, reducing resistance and allowing higher speeds than a pure displacement hull, though it doesn’t reach the full sprint of a pure planing hull. This gives a practical balance between range, stability, and faster response when needed.

Coast Guard boats use this type because they need to cruise efficiently over long distances while still being able to accelerate to respond quickly to incidents, especially in rough seas where stability and range matter.

Other hull types either sacrifice efficiency at speed (pure planing) or speed at efficiency (pure displacement), and deep-V designs are typically associated with planing configurations rather than the mixed characteristics described here.