Tonnage

High Quality Content by WIKIPEDIA articles! The terms "Tonnage" and "Ton" have different meanings and are often confused. Tonnage is a measure of the size or cargo capacity of a ship. The term derives from the taxation paid on tuns of wine, and was later used in reference to the weight of a ship's cargo; however, in modern maritime usage, "tonnage" specifically refers to a calculation of the volume or cargo volume of a ship. The term is still sometimes incorrectly used to refer to the weight of a loaded or empty vessel. Measurement of tonnage can be less than straightforward, not least because it is used to assess fees on commercial shipping.