Why class displacement is not one exact number

Quoted displacement figures should not be read as identical weights for every ship. A class may be designed around a round target while individual hulls vary because of steel thickness, alloy composition, construction tolerances, and later additions. Soviet institutional pressure could encourage reports that a goal had been met exactly even when the completed ship differed. British Tribal-class destroyers were reported at 1,850 tons standard displacement under treaty obligations, although individual ships were lighter or heavier. The comparison is a practical caveat for evaluating warship specifications across sources.