Merchant gross register tonnage and a warship's standard displacement measure different things. The merchant figure is associated with carrying capacity and the load line, while standard displacement describes the ship's own weight in a defined condition. A merchantman and a warship therefore cannot be compared by treating every quoted ton as equivalent. The distinction prevents a misleading specifications comparison, although this short explanation does not attempt a full definition of either measure.
Notable Point · 34:13-34:47
Why merchant tonnage and warship displacement differ
A short technical aside distinguishes a merchant carrying-capacity measure from the displacement figures used for warships.