Spain had treaty freedom to protect its two flagships

At almost 11,000 tons standard, the class still offered too little protection to make a persuasive case for escalating treaty cruiser limits. Spain's older Almirante Cervera light cruisers had belts between two and three inches thick, decks between one and two inches, and six-inch conning-tower armour. Spain had not signed the Washington Naval Treaty, and the Vickers-operated yard was technically owned by the Spanish government, so treaty compliance did not compel the compromise. A design of about 11,500 tons, or a little more, is suggested as a way to retain the desired capabilities and add useful protection, subject to Spanish industrial limits. Nelson and Rodney provide the comparison: as the Royal Navy's only two 16-inch battleships, they sacrificed speed for armour. Spain's two intended flagships had a similar claim on protection because there were so few of them.