The Bisson-class example is used to show a stated speed range of roughly 30 to 32 knots and a displacement difference of 36 tons. That is a meaningful variance for relatively small destroyers rather than a negligible rounding error. Speed affects screening, scouting, and the ability to coordinate with a larger formation, while displacement differences can reflect changes made during a building programme. It is a reminder that class labels do not always describe identical ships.
Notable Point · 1:07:55-1:08:16
Variation within the Bisson-class destroyers
A short design comparison shows how ships grouped in one destroyer class could still differ materially in speed and displacement.