The speed margin needed to control a battle

A small speed advantage is useful but does not automatically permit escape from accurate heavy-gun fire. The rule of thumb offered here gives equivalent ships about three knots to dictate the pace of battle. A battlecruiser facing a battleship may need five or six knots because it must withdraw in good order before the heavier ship's practised gunnery settles on the target. The Japanese squadron's theoretical two-knot edge falls below either threshold. Armour differences elsewhere in the design further reduce the value of relying on speed alone.