Hydrofoils are wing-like structures attached to the hull of a boat that lift the vessel above the water's surface as it gains speed. This design reduces drag and allows for faster travel, making hydrofoils popular in various watercraft, including ferries and racing boats. When a hydrofoil is submerged, it generates lift, similar to how an airplane wing works in the air. As the boat accelerates, the hydrofoils rise, creating a smoother ride and improving fuel efficiency. Hydrofoils can be found in both recreational and commercial applications, showcasing their versatility in marine technology.