The penalty of a sliding-breech 18-inch turret

How large would a German twin 18-inch turret be if it retained sliding breech blocks?

Enormous: the panel estimates that a British quadruple 16-inch turret could fit in about the same footprint.

The panel's rough comparison gives a German twin 18-inch turret with sliding breech blocks about the same footprint as a British quadruple 16-inch turret. That estimate makes the breech arrangement a major constraint on the proposed installation. No detailed dimensions or weight calculations accompany it. It remains an informal comparison of how much space different heavy-gun arrangements could require.