Speed is most valuable when it creates a large proportional advantage over the ships a force must fight or evade. Moving from 18 to 24 knots or from 21 to 28 knots increases speed by roughly one third, enough to shape interception and disengagement. Moving from 36 to 40 knots gains only about one ninth while demanding increasingly powerful machinery and escorts that can keep pace. For the technology under discussion, useful battlecruiser speed falls in the 33-to-36-knot range. Once both sides can reach that band, matching the opponent and spending the remaining displacement on armor and subdivision may produce more strategic value than chasing four additional knots.
Notable Point · 1:01:39-1:05:57
Why battlecruiser speed produces diminishing returns
The tactical freedom gained from extra knots shrinks as capital ships become faster, making protection a better investment beyond a useful threshold.