Heavy armour helps a ship endure punishment and keep fighting, while an isolated surface raider needs to preserve mobility and avoid damage requiring repairs. That tension raises the possibility that a battlecruiser would be a better raiding tool. Scharnhorst and Gneisenau illustrate the problem when they try to draw an R-class battleship away from its convoy. The escort can refuse pursuit, forcing the faster German ships to attack on its terms if they want the merchant ships. Even a German victory could leave damage that prevents escape when other Royal Navy heavy units arrive. The likely consequences of the fight can therefore deter an attack even if the escort would probably lose.
Notable Point · 1:51:34-1:53:35
Why a slow battleship could frustrate faster surface raiders
A convoy-escort example explains why Scharnhorst and Gneisenau could be deterred by an older battleship they might defeat at considerable cost.