Convert Ton Register (ton reg) to Acre-Foot (US Survey) (ac*ft (US)) instantly.
About these units
Ton Register (ton reg)
A register ton, or ton register, is a unit of volume, not mass, equal to 100 cubic feet. It is used in maritime contexts to measure the internal capacity of ships—specifically cargo-carrying volume, not weight. Ship registries rely on register tons to calculate taxes, port fees, and cargo classifications. The unit dates back to 19th-century maritime law, where consistent volumetric measurement was critical for international shipping regulation. Despite changes in global trade and containerization, register tons remain important for historical vessel documentation, as well as for understanding older merchant and naval ship specifications.
Acre-Foot (US Survey) (ac*ft (US))
The US survey acre-foot differs extremely slightly from the international acre-foot due to the slight difference between the survey foot and the international foot. While the distinction is negligible in most contexts, it is important in surveying, legal water rights, and long-term hydrological accounting, especially in regions where large historical datasets were recorded using US survey measures. This variant highlights how even subtle unit differences can have major implications when dealing with huge volumes over long timescales, such as state water budgets and inter-state compacts.