The Royal Navy's paper N3 design might have traded some maximum protection for 27 or 28 knots if rival 30-knot battleships became real. A two-knot disadvantage would not make pursuit hopeless because weather, machinery condition, or a lucky hit could erase it. The faster ship would also struggle to dictate range reliably when its advantage was so small. A margin of three to four knots is presented as the point where speed becomes dependable tactical control rather than a paper advantage.
Notable Point · 41:31-42:55
How much speed is needed to control the range
The closing design comparison argues that a 28-knot battleship could still threaten a 30-knot opponent because a two-knot edge is too small to guarantee control of the engagement.