In the competitive ferry industry, ships often change operators, especially in Europe. Other ferries have alternated between summer service in the northern and southern hemispheres every six months. Some Incat vessels of the 1990s have been operated by up to six shipping companies with regular name changes.

Gross 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.