A maximum armour figure describes the thickest protection, without showing how much of the hull it covers. Battleships and battlecruisers could distribute their protection across different areas even when individual thicknesses looked comparable. The comparison here places battlecruiser schemes closer to selective, all-or-nothing protection earlier than contemporary battleships, whose turtleback schemes provide the contrast. Judging protection therefore requires the extent and arrangement of the armour as well as its maximum thickness.
Notable Point · 25:06-25:57
Why armour coverage matters alongside maximum thickness
Comparing the area protected explains why maximum belt thickness alone gives an incomplete picture of a capital ship's armour.