Term: gross tonnage (maritime)
The overall volume of a ship's hull, including crew cabins, storerooms and machinery spaces. A ton equals 100 cubic feet. The calculation of tonnage is complex, and a major revision in tonnage calculation laws occurred in 1864. The term "old measurement"
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[Source: "Glossary." Wisconsin's Great Lakes Shipwrecks (http://www.wisconsinshipwrecks.org/)]