Nothing Remains Static: The Never Built G3, Amagi, and Lexington Class Battle Cruisers


Artists Depiction of G3 Battlecruiser 

Friends of Padre Steve’s World,

This weekend I will be reflecting on the old year and the coming new year, but tonight I decided to tweak and republish an article from about four years ago dealing with the battle cruisers being built by Great Britain, Japan, and the United States after the First World War. They represented the pinnacle of naval design for their era and would have been far superior to their adversaries had technology and war remained static. As Admiral Ernest King noted:

“Nothing remains static in war or military weapons, and it is consequently often dangerous to rely on courses suggested by apparent similarities in the past.”

As the First World War ended a new Naval Race was heating up. The United States had announced its intention during the war to build a navy second to none while Imperial Japan was making plans for a fleet that would give it superiority in the Western Pacific. The British, though still be far the largest naval power in the world were burdened by the massive costs of war and empire, but also seeking to maintain their naval dominance and to that end they were in the process of building a class of massive super-Dreadnought battleships, and Battle Cruisers.

The ships known as battle cruisers were first built by the British Royal Navy as a compliment to the all big gun Dreadnought battleships. The Battle Cruiser concept was for a ship of roughly the same size and firepower as a Battleship but sacrificing protection for greater speed, endurance and range.  and Japan joined in the Battle Cruiser race before and during the war. Unlike Britain the United States had concentrated on building battleships but following the war began to design and build its own class of massive battle cruisers.


HMS Invincible Blowing Up at Jutland 

During the war the weaknesses of the type were exposed during the Battle of Jutland where three British Battle Cruisers, the HMS InvincibleHMS Indefatigable and HMS Queen Mary blew up with the loss of most of their crews; of the 3311 officers and sailors on the ships only 26 survived. The HMS Lion was almost lost in a similar manner but the heroic actions of her crew saved her from her sisters fate. The British ships had glaring deficiencies in armor protection and the arrangement of their ammunition magazines and hoists which certainly contributed to their loss. Their German counterparts on the other hand proved much tougher and though all sustained heavy damage while engaging British Battleships and Battle Cruisers, only one the Lützow was lost. She absorbed over 30 hits from large caliber shells and only lost 128 crew members.


HMS Hood

As the war progressed other Battle Cruisers were built, the British launched the HMS Repulse and HMS Renown and completed the HMS Hood shortly after the war was over. The Japanese built the four ship Kongo class from a British design, the first of which, the Kongo was completed in a British yard. As the powers embarked on the next Naval Race planners and naval architects designed ships of massive firepower, better protection and higher range and speed. All would have been better classed as Fast Battleships.

The British designed and began construction on the G3 class in 1921, while the Japanese began work on the Amagi Class, and the United States the Lexington Class. However the construction and completion of these ships as Battle Cruisers was prevented by the Washington Naval Treaty.

invincible 490

The treaty, which was ratified in 1922 limited the United States and Great Britain to a maximum of 525,000 tons in their battle ship fleets and 125,000 tons in aircraft carriers.  The Japanese agreed to a limit of 315,000 tons and the French and Italians 175,000 tons each. Tonnage for battleships was limited to a maximum of 35,000 tons with a limitation on guns size to 16 inches.  Since the bulk of the ships planned or being built by the US and Japan exceeded those limits they would be effected more than the British whose post war shipbuilding program had not begun in earnest, in fact the G3 Class had just been approved for construction.

The G3 class would have comprised four ships and been similar to the N3 Class Battleships. They were very well balanced ships and would have mounted nine 16” guns in three turrets on a displacement of 49,200 tons and deep load of 54,774 tons. They had an all or nothing protection plan meaning that the armored belt was concentrated in vital areas around the armored citadel, conning tower, turrets and magazines and engineering spaces. Their armor belt would have ranged from 12-14 inches, deck armor from 3-8 inches, conning tower 8 inches, barbettes 11-14 inches, turrets 13-17 inches and bulkheads 10-12 inches. Their propulsion system of 20 small tube boilers powering 4 geared steam turbines connected to 4 propeller shafts would have produced 160,000 shp with a designed speed of 32 knots.

The four ships, none of which were named were ordered between October and November of 1921. Their construction was suspended on November 18th 1921 and they and the N3 Battleships were cancelled in February 1922 due to the limitations of the Washington Naval Treaty. Many concepts of their design were incorporated in the Nelson Class battleships which were a compromise design built to stay within the limits of the treaty.


Amagi Class as Designed, Akagi as Completed (below) 


The four planned Japanese Amagi Class ships would have mounted ten 16” guns on a displacement of 47,000 tons at full load. Their propulsion system 19 Kampon boilers powering four Gihon turbines would have given them a maximum speed of 30 knots, They would have had less protection than the G3 ships being more of a traditional Battle Cruiser design. As a result of the Washington Naval Treaty the Japanese elected to convert two of the ships, the Amagi and Akagi to aircraft carriers. Amagi was destroyed on the ways during the great Tokyo earthquake and Akagi was completed as a carrier. The other two vessels were scrapped on the ways.




The United States Navy planned the six ship Lexington Class. These ships would have mounted eight 16” guns on a ship measuring 874 feet long and 105 feet in beam, displacing 43,254 tons at full load, or nearly the size of the Iowa Class battleships. They would have had a maximum speed of 33 knots being powered by 16 boilers which drove 4 GE electric turbines producing 180,000 shaft horse power. Theirs was a massive engineering plant and while the class did not have as heavy armor protection as either the G3 or Amagi classes, they were superior to them in speed as well as endurance. Upon ratification of the Washington Naval Treaty four of the six ships were cancelled and the remaining two, the Lexington and Saratoga competed as aircraft carriers.  Had any of the ships been completed as Battle Cruisers it is likely due to their speed that they would have operated primarily with the the carriers that the US Navy built during the 1930s.


One can only speculate what the navies of World War II would have looked like had the Washington and the subsequent London Naval Treaties not been ratified. One can also only imagine how the war at sea would have been different had the ships completed as carriers been completed as Battle Cruisers.

However that was not to be, of the planned 14 ships of these three classes only three were completed, all as aircraft carriers, ships that helped to forge the future of naval operations and warfare for nearly a century. Thus the uncompleted ships are an interesting footnote in naval history yet have their own mystique. and one might wonder if the new aircraft carriers currently being built by the United States, Britain, China, India and other nations will also be displaced by advancing technology as were these ships.

Until tomorrow,


Padre Steve+


Filed under History, Military, Navy Ships, US Navy

5 responses to “Nothing Remains Static: The Never Built G3, Amagi, and Lexington Class Battle Cruisers

  1. David W. Harris

    A fascinating episode in naval history, a post dealing with the proposed battleship classes would be very welcome. The battle cruiser concept is often criticised as being deeply flawed from the outset, in fact I can only think of one instance when concept was enacted as Admiral Lord Fisher had intended it should be. The correct use of a battle cruiser was to destroy an armoured cruiser, this was exactly what happened at the battle of the Falkland Islands. The criticism of battlecruisers should correctly be addressed to the misuse of battlecruisers in the role of battleships or in the scouting role which is correctly the preserve of light cruisers. Never the less some very good work was effected by battlecruisers in both the great wars of the twentieth century.

    • padresteve

      Totally agree, they were not meant to be in the line of battle. Chasing down raiders, engaging other battle cruisers, and later escorting carrier and task forces or making surface raids on shore targets like the fast battleships did against Japan in 1945.

      • super390

        But isn’t it inherent in the nature of a democracy that the capabilities of expensive weapons are oversold to get them funded, and a belief takes hold even within the military that the overselling is the truth? Interesting that the authoritarian Germans and Japanese seemed able to get reasonably well-protected battlecruisers built, and properly used, in the World Wars. No parliamentarians to harass Naval Ministers to put the most expensive ships into the battle line over there.

        Then again, my own feelings about these ships are so illogical that I have to wonder where I’m coming from. Perhaps it is precisely because the battlecruiser is a concept so extreme, extravagant, and narrow that it has a romantic appeal even greater than the battleship. Or the aircraft carrier. Science fiction is full of space battlecruisers, more than battleships. The Hood and its unbuilt responses exist in a fantasy World War 2 where aircraft do not herald the coming flash of the mushroom cloud and the megadeath-by-hand that went on inland goes unseen. The battlecruiser Lexington is an obsession of mine, yet the carrier Lexington was better at every one of the former’s intended functions. The same was true of the Akagi. But no one has ever called a carrier duel romantic.

    • super390

      It was interesting for me to learn as I delved back into warship history (it’s been forty years since I prowled the libraries at Kadena Air Base and the Universities of Houston and Michigan) to learn that in 1916 the heavy cruiser did not exist. Light cruisers were hardly more than stretched destroyers. Naval architects with wartime blank checks were playing with all sorts of idea for midsize armored ships, with guns up to 12″. A British anomaly, the HMS Hawkins, caused a great furor among the rival Allies. In fact it violated Britain’s imperial interest in cheap light cruisers that could be launched in bulk. The British wisely conceded further such construction at the Washington Treaty, and the Hawkins’ specs were the basis of the Treaty’s limitations on cruisers. With all the armored cruisers being scrapped, can we say that the fast, somewhat-armored heavy cruisers built under the Treaty accidentally proved to be the Killer App that the battlecruiser failed to be? Cheap enough to put in harm’s way, numerous enough to escort any kind of ship, guns powerful enough for fire support.

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