Churchill blamed Cradock for failing to concentrate around HMS Canopus and argued that, without her, he should have followed von Spee until reinforcements arrived. The opposing account points out that the Admiralty had separated a squadron on South America's east coast, leaving neither British force adequately equipped for the German squadron. The engineer Phillips also challenged the idea that Canopus offered absolute protection. His rebuttal put her older 12-inch guns' range at 13,500 yards against 16,000 yards for the German cruisers' 8.3-inch guns, allowing them to remain outside her reach. He compared Canopus's Harvey armour unfavourably with the German ships' Krupp armour despite similar thickness. These were the technical grounds for disputing Churchill's use of Canopus as a secure centre for Cradock's force. The word battleship alone could not settle that argument.
Chapter · 23:10-24:26
Canopus could not guarantee Cradock's safety
The technical comparison behind Churchill's Coronel defense shows why calling HMS Canopus a battleship did not make her an invulnerable shield against von Spee's cruisers.