What do planning hulls generally do in terms of movement on water?

Planning hulls are designed to lift out of the water as they gain speed, allowing them to ride on top of the water's surface. This design helps reduce drag, which enhances fuel efficiency and allows for higher speeds. By minimizing water contact, planning hulls can transition from displacement mode, where the entire hull is submerged and displaces water, to planing mode, where the hull rises and skims across the top of the water. This characteristic makes planning hulls ideal for activities like water skiing, racing, and other high-speed maneuvers, providing both performance and agility.