The Awesome Alaska Class: America’s (Not Quite) Battlecruisers

 
 

War History online proudly presents this Guest Piece from Chris Knupp

This class of cruiser is perhaps one of the more confusing ships ever put to sea by the United States. Designed to prowl the oceans and hunt down enemy commerce raiders, they possessed high speed and considerable firepower. Vastly more powerfully than typical cruisers and at a disadvantage against battleships, the classification of these ships has divided historians. Today, we look at the unique features and challenging design history of these warships and try to find where they fit.

The Idea behind the Alaska Class

The forerunner to the Alaska class design got its start as a result of the introduction of the German “pocket battleships.” Well armed and with a respectable speed, they posed a threat to merchant vessels. Britain, France, and the United States all worked on new designs intended to counter this threat. However, for the US, the designs remained on the drawing board. They would be resurrected years later following rumors of supposed “super cruisers” Japan was thought to be building. While some in the Navy felt that designing ships solely to hunt down commerce raiders was a waste of resources, others thought the threat was grave enough to warrant these new vessels. President Franklin D. Roosevelt was one such proponent of these new cruisers and strongly pushed for their construction. It is possible that the Alaska class was created as a result of politics rather than wartime thinking.

Pocket Battleship. The “pocket battleships” of the German Navy. Their introduction caused considerable alarm among many rival navies. They influenced the early designs for the future Alaska class cruisers.

A ship born from politics would certainly explain the confusing design process. The designers initially had no clear idea on what role the ship was to perform and produced a wide variety of designs. At one point there were no less than nine separate designs. Designs ranged from 6,000 ton fast cruisers to enlarged heavy cruisers and even a 38,000 ton “light” battleship. However, General Board finally settled on a design that was essentially an enlarged Baltimore class heavy cruiser. The reuse of a hull design coupled with the adoption of the machinery from the Essex class carriers suggests that designs attempted to save money. They were also ordered at a time when Japan was known to possess a very powerful fleet of cruisers. It is possible that utilizing existing components might have accelerated development of these ships to counter the threat of Japan’s cruisers. Perhaps aware of the increasing power of aircraft carriers, designers were also quick to ensure the ships would be well suited to screening the carriers as well.

The Design Features of the Alaska Class

Alaska Forward Battery. The 12″/50 Mark 8 of the Alaska class. Despite their size, they were very powerful weapons.

 

Firepower

Being the middle ground between battleship and cruiser, it was only natural that the Alaska class carry an intermediate weapon. The 12″/50 Mark 8 Naval gun was a return to a barrel size not used by the US in over three decades. However, the Mark 8 represented an entirely different breed of naval cannon. Like the larger 16″ weapons of the US battleships, the Alaska class received their own “super heavy” shells. When firing these shells, the Mark 8 offered performance slightly superior to that of US battleships mounting 14″ naval guns. In this regard, the Mark 8 could be considered the most powerful naval gun of World War 2 in terms of size. Had the Alaska class ever had the opportunity to fight the German raiders or Japanese super cruisers, they would have had an impressive advantage in firepower.

Baltimore Class Cruiser Profile.

When compared to the Baltimore class cruiser, one can immediately spot the similarities in the arrangement of the secondary weapons. The arrangement of the 5″ secondary guns is immediately clear with the dual port and starboard mounts. Two additional mounts are superfiring over the main cannons. Even the 40mm and 20mm Anti-air weapons are arranged in a similar manner.

Of particular note in the photos is the location of the aircraft catapults. Despite being based on the Baltimore class, the Alaska class opted for the amidships aircraft catapults like older US cruisers. Some felt this was detrimental as the location could have housed additional 5″ gun mounts and increased anti-aircraft weaponry.

Armor

Armor would prove to be the greatest weakness of the Alaska class. Being designed as “cruiser killers” they were essentially designed to resist cruiser guns and not much else.In an effort to reduce weight, the Alaska class cruisers were designed without a torpedo defense system. What little protection they had was against a 700lb warhead at a time when Japan was fielding torpedoes with 1100lbs of explosives.

What the Alaska class lacked in underwater protection, they made up for it in gunfire protection. Against 8″ cruiser gunfire, they were protected at 10k to 30k yards. Even the larger German 11″ shell would have difficulty penetrating the belt at typical combat ranges. Had the Alaska class gotten the chance to actually hunt down Axis cruisers, they would have been formidable opponents.

On the subject of protection, it should be noted that the Alaska class devoted only 28.4% of their tonnage to armor compared to the 32% or more that battleships typically did. Battlecruisers traditionally devoted anywhere from 19.5% (HMS Invincible),29% (Lexington class Battlecruiser), and even up to 32% (HMS Hood) of their tonnage to armor, a category the Alaska class squarely falls into.