What is the primary feature of planing hulls?

The primary feature of planing hulls is that they glide on top of the water at higher speeds. This design allows the boat to rise above the water's surface rather than pushing through it, which reduces drag and enhances speed. When a planing hull reaches a certain speed, it creates lift, allowing it to skim over the water rather than being fully submerged. This capability makes planing hulls particularly suitable for recreational activities such as water skiing and fast cruising, where speed and maneuverability are crucial.

The other features mentioned are characteristic of different hull types. For instance, hulls that displace a large volume of water are typically displacement hulls, which are designed for stability but move slower. In contrast, hulls designed for stability in rough waters usually feature a more pronounced shape that can handle waves better, which is not the primary trait of a planing hull. Lastly, round-bottomed hulls are generally not associated with planing; instead, they are more stable at lower speeds. Planing hulls usually have a flatter bottom that facilitates quick ascension to a higher speed.