In design and armor the "Alaska" class are regarded as "large cruisers" rather than battlecruisers. Their design was scaled up from , the latter being a treaty cruiser limited by the Washington, 1930 London and Second London naval treaties. Their armor scheme had sufficient gunfire protection not only against 8″ heavy cruiser shells but even the larger 11″ shells used by Germany's "pocket battleships" and . However, they lacked the underwater protection systems found on full-fledged battleships and even intermediate capital ships like the French and German classes. This left the "Alaska"s virtually defenseless against torpedoes, as well as vulnerable to shells falling slightly short and continuing underwater to hit the hull.