There are two common types of container handling gantry crane: high profile, where the boom is hinged at the waterside of the crane structure and lifted in the air to clear the ships for navigation, and low profile, where the boom is shuttled toward and over the ship to allow the trolley to load and discharge containers. Low-profile cranes are used where they may be in the flight path of aircraft, such as where a container terminal is located close to an airport. The type of crane selected in container terminal design process is determined by the design vessel and local environment.