Malaccamax is a class of cargo ship. As the name suggests, it refers to the largest size of ship that can fit through the Strait of Malacca, which lies between the Malay Peninsula and the Indonesian island of Sumatra. The straight is rather wide, so in this case, the controlling measurement is the minimum depth of the strait, which is just 25 meters (82 feet) at its shallowest point. Accordingly, a typical Malaccamax tanker or dry bulk freighter will have a length of 333 meters (1,093 feet), beam of 60 meters (197 feet), draught of 20.5 meters (67.3 feet), and dry weight tonnage of 300,000.
As the shortest path between Asian manufacturing powerhouses like China and Japan and other major world economic zones such as South Asia, East Africa, the Middle East, and Europe, the Straight of Malacca is one of the most important and busiest sea lanes in the world. Even the slight detour to go around the island of Sumatra can make a difference of hundreds of thousands of dollars per voyage in fuel costs and lost transit time, making the Malaccamax size a particularly useful parameter to consider when designing large cargo ships.
Similar terms include Panamax, Suezmax, and Seawaymax, which refer to the largest ships capable of passing through the Panama Canal, Suez Canal, and Saint Lawrence Seaway, respectively.