Tonnage and poundage to be one of the complaints of his Long Parliament. The refusal of and subsequent disputes about tonnage and poundage rights is seen as one of the many events bearing responsibility for the English Civil War. Tonnage and poundage Tonnage and Poundage were certain duties and taxes first levied in Edward II's reign on every tun (cask) of imported wine, which came mostly from Spain and Portugal, and on every pound weight of merchandise exported or imported. Traditionally tonnage and poundage was granted by Parliament to the king for life until the reign of Charles I. Tonnage and poundage were
Tonnage less the volume of spaces that do not hold cargo (e.g., engine compartment, helm station, and crew spaces, again with differences depending on which port or country does the calculations). It represents the volume of the ship available for transporting freight or passengers. It was replaced by "net tonnage" in 1994, under the Tonnage Measurement convention of 1969. The Panama Canal/Universal Measurement System (PC/UMS) is based on "net tonnage", modified for Panama Canal purposes. PC/UMS is based on a mathematical formula to calculate a vessel's total volume; one PC/UMS net ton is equivalent to 100 cubic feet of capacity. Suez