The battle gives a clear role-substitution lesson. Canada provides backup while the formation closes under orders to avoid torpedoes. The so-called battlecruiser counterpart is really doing heavy-cruiser work because the available cruiser designs were unsatisfactory. Its 9.2-inch, 6-inch, and 3-inch battery is meant to tear apart cruisers and destroyers rather than fight like a conventional capital ship. Canada's twelve 15-inch guns supply the capital-ship weight behind it, so the improvised heavy cruiser works as part of a layered force rather than alone.
Notable Point · 1:40:57-1:48:57
Battlecruiser as heavy-cruiser substitute
A battlecruiser action explains why a navy might use a much larger ship to fill a heavy-cruiser role it cannot design satisfactorily.