A Suezmax is the largest type of ship that can pass through the Suez Canal. The word "suezmax" is a common term used in naval architecture to refer to how far below and above the waterline the craft can go. While sailing through the canal, a ship has limited depth due to water level and height restrictions because it must go under the Suez Canal Bridge. Typically, a craft that can manage a depth of about 66 feet (20.1 meters) and a height of 223.1 feet (68 meters) is under or exactly at Suezmax specifications.
Ships in the Suezmax category are primarily tankers. These craft typically carry crude oil and chemicals. They can usually make it through the canal with up to 240,000 tons of deadweight (DWT). In order to conform to canal specifications, the ship must fall far below that weight as the number includes the weight of cargo, the ship, crew, and any other equipment.
Changes in the depth of the canal over the years have changed the specifications of Suezmax ships. For example, in 2009 a major change increased the depth from 60 to 66 feet (18 to 20 meters). These changes are tracked on charts created by the Suez Canal Authority, which naval architects and builders can use as a resource when designing and constructing new ships.
If the height, width, or weight of a ship goes over the Suezmax parameters, there are several ways to handle the problem. Some ships will avoid the canal and sail around the southern tip of Africa. Others will unload cargo and transport it via other means through the canal.
The process of removing cargo to other forms of transportation is known as transhipment. Usually extra cargo is temporarily moved to other vessels and then returned to the main ship after transport through the canal. Some cargo may also be moved through pipes, commonly known as pipeline terminals.
Other common types of ships that travel through the Suez Canal include very large crude carriers (VLCCs) and the Aframax. VLCCs are supertankers and tend to require transhipment as they are usually too heavily loaded to travel through the canal. Aframax ships travel well through the canal because they are smaller than both Suezmax and VLCC craft. In order to increase efficiency of transport, VLCCs have become less common for canal transport while the other two models have grown in popularity.