What is the primary feature of a Panamax ship?

The primary feature of a Panamax ship is that it is specifically designed to pass through the locks of the Panama Canal. This design limitation is significant because the dimensions of the Panama Canal locks dictate the maximum size of the vessels that can transit through them. The term "Panamax" refers to the maximum allowable dimensions for ships navigating this key waterway.

Panamax vessels typically have specific dimensions: they must not exceed a length of around 965 feet (294.1 meters), a breadth of approximately 106 feet (32.3 meters), and a draft not exceeding 39.5 feet (12.0 meters) when the canal is at its regular water level. These restrictions ensure that the ships can be accommodated safely within the confines of the locks during transit.

While other features, such as cargo capacity or engine efficiency, may be important in assessing a ship's capabilities, the defining characteristic that sets Panamax ships apart is their design for Panama Canal navigation. This specifically addresses the constraints imposed by the canal infrastructure.