Tonnage is a measure of a ship's enclosed volume rather than its weight or displacement, so similar ships can have differing Gross Tonnages due to factors such as if a viewing platform is fully enclosed or open to the weather. References External links Official website Revolution Design, Incat's in house naval architects Companies based in Hobart Shipbuilding companies of Australia Shipyards of Australia Vehicle manufacturing companies established in 1977 1977 establishments in Australia