Treaty Cruiser

The United States built 18 heavy cruisers and nine light cruisers subject to the 1922 and 1930 Naval Arms Limitation Treaties. These were known as Treaty Cruisers, but to those who built them, they were the "tin clads." To those men that fought on them, the term tin clad was unacceptable, as they proved to be efficient and beautiful fighting ships.

1921 - Washington Naval Conference

At the 1921-1922 Conference on the Limitation of Armament, the United States proposed an aggregate tonnage limitation on "auxiliary surface combatant craft" which included cruisers (exclusive of battle cruisers), flotilla leaders, destroyers, and all other surface types except those specifically exempted. Existing monitors, unarmored surface craft under 3,000 tons, fuel ships, supply ships, tenders, repair ships, tugs, mine sweepers, and vessels readily convertible from merchant vessels were exempt from the terms of this agreement. No new auxiliary combatant craft would be built exempt from this agreement regarding limitation of naval armaments that exceed 3,000 tons displacement and 15 knots speed, and carry more than four 5-inch guns. No surface vessel carrying guns of caliber greater than 8 inches shall be laid down as replacement tonnage for auxiliary combatant surface craft.

The understanding of France was that the conference contemplated that cruisers would be used as means of communication with colonial possessions, and in this respect long distances must be covered. These vessels should, therefore, be able to offer sufficient conditions of well-being for their crew and passengers. In order to offer proper conditions of stability, they might also require a tonnage superior to 10,000 tons. France took the position that the difference between cruisers and capital ships had already been fixed by settling a maximum for the caliber of their guns at 8 inches, and saw no sufficient reason for further restrictions on displacement set at 10,000 tons, proposed by the UK.

The British delegation was of the view that the possibility of a cruiser of 20,000 or 30,000 tons, bristling with 8-inch guns, and possibly large enough to carry large bodies of troops to the colonies, was one which could hardly contribute toward the reduction of expenditure on armaments. Great Britain, for example, was not in a financial position to bear the burden of such an expenditure. Admiral de Bon of France had said that 10,000 tons was rather small from the point of view of commodiousness and habitability. Speaking as a layman, the larger the ship he had to travel in, the better was he pleased.

The British delegation was of the view that 10,000 tons was a very ample size for a cruiser, and this figure had been selected because at the present time no light cruisers of even this tonnage were being built in any country, and the British delegation therefore thought it was a good opportunity to put an end there and then to the development of this type of vessel. The UK was under the impression that the allowance was very liberal, in view of the tonnage being adopted for cruisers now under construction. The new cruisers then building for the United States Government were of 7,500 tons burden, and the French light cruisers were of 8,000 tons.

Baron Kato said that on behalf of the Japanese delegation he accepted the proposal to limit the tonnage of light cruisers to 10,000 and the caliber of guns carried by such ships not to exceed 8 inches.

Vessels other than capital ships and aircraft carriers are not covered by the 1922 agreement. They may therefore be built, but there is a limitation upon warcraft smaller than capital ships, and which experts considered more effective weapons. For example, Article XI provides that "No vessel of war exceeding 10,000 tons (10,160 metric tons) standard displacement, other than a capital ship or aircraft carrier, shall be acquired by, or constructed by, for, or within the jurisdiction of, any of the Contracting Powers." This is a limitation of no mean value upon the size. There is also a limitation upon the guns which such vessels shall carry; thus, the same article provides that "No vessel of war of any of the Contracting Powers, hereafter laid down, other than a capital ship, shall carry a gun with a calibre in excess of 8 inches (203 millimetres)."

Thus the 1922 Conference defined cruisers as having a diplacement of no more than 10,000 tons, mounting guns no greater than 8 inches. It is notable that these specifications correspond approximately to those of a British Hawkins class cruiser.

The Treaty measured the displacement of the ships based on their 'standard displacement", a weight accounting methodology defined within the Treaty. The intent of the standard displacement was to avoid unfairly penalizing Great Britain and the United States for the large steaming distances the two countries required. Standard displacement did not count the weight of the fuel and reserve feed water needed for long range against the Treaty limits.

This had an immediate and dramatic effect on ship design within the United States. For the first time, weight estimation, control, and reduction moved to the forefront of design drivers for new ship designs. The US had not invested resources in investigating weight reduction measures in the years preceding the Treaty implementation. Additionally, US designers were suddenly trying to design a ship that would be just under the Treaty limits without fuel weight, while meeting speed and range requirements which are naturally tied to the amount of fuel onboard.

The bizarre effects of the Treaty were also evident in all of the US Navy conceptual designs coming after the Treaty's implementation. For each, the potable water, which might be excluded from standard displacement, was carried in the turret overhangs, and thus balance secured without added (Treaty) weight.

The limitations on the cruiser displacement and armament were not arbitrarily assigned, rather they were a rationally arrived upon set of restrictions due to the world's intention to maintain parity with rival nations' capabilities. By this time the US Navy had two years of experience designing 10,000 ton, 8-inch cruisers and had convinced itself that nothing smaller was really worth building, considering Pacific distances. The British Hawkins class cruisers had already made the 8-inch gun cruiser the standard for long range cruisers in every nation, and agreeing to the 10,000 ton displacement limit and 8-inch armament limitation was naturally amenable to the US.

This had the immediate, if unintentional, effect of simultaneously creating both an upper and lower bound of future cruiser designs. While the Treaty did indeed curtail the arms race of building capital ships, it inadvertently supplanted this contest with a new arms race of building "Treaty cruisers."

1927 - Geneva Naval Conference

Though the Five-Power Treaty of 1922 controlled tonnage of each navy's warships, some classes of ships were left unrestricted. As a result, a new race to build cruisers emerged after 1922, leading the powers back to the negotiating table in 1927 and 1930 to close the remaining loopholes in the agreements.

The heavy cruiser race began in earnest in 1922 with Japan's announcement of a major construction program of cruisers, destroyers, and submarines. The British, Americans, French and Italians soon followed suit. The first attempts to curtail the buildup began in 1925 through the League of Nations. These talks and a second series of talks in 1927 in Geneva both failed. The United States and Britain were fundamentally at odds on the issue of heavy cruiser buildup.

The British preference was for smaller cruisers because they were easier to build and maintain across the vast British Empire. The existence of heavy cruisers was an obvious threat to a predominantly light cruiser oriented British fleet. The British did, however, need heavy cruisers for working with the fleet. Therefore, their position was not to eliminate the heavy cruiser, but to limit its numbers.

For the American fleet, trade protection was not a major consideration. The US needed to maintain naval communications out to the Philippines in the Far East. Large cruisers were vital, since American refueling facilities and naval bases in the Pacific were few. The American position was to maintain the current restrictions set forth in the Washington Naval Treaty, but to control escalating costs by restricting the numbers built by the negotiating navies.

The Japanese had very little use for light cruisers as trade protection was not a major concern. They instead required cruisers which could work with the fleet. The Japanese wanted parity with their American and British counterparts, and to maintain the Washington Naval Treaty restrictions concerning heavy cruisers.

The Three Power Geneva Naval Conference of 1927 was a gathering of the United States, Great Britain and Japan. Great Britain proposed dividing the classes of cruisers into "heavy" and "light," so that heavy cruisers did not exceed 10,000 tons, and light cruisers did not exceed 7,000. The British problem was that they had extensive worldwide shipping routes to patrol they needed more not larger ships, a larger number of smaller ships unsuited to American needs. As the British had a far greater need for light cruisers, it proposed limiting production of heavy cruisers, while including more freedom for building those in the lighter class. They proposed an overall cruiser limit of 70 ships and 600,000 tons. This plan would have required the United States to build as many as thirty new heavy cruisers just to maintain parity between the two nations, thus sparking an arms race instead of disarmament. Japan proved to be the most flexible party with regard to the cruiser limitations, but preferred that a 10:10:7 ratio be applied to auxiliary craft, rather than the Washington Conference ratio of 5:5:3.

The differences between the parties emerged in several areas. There was a dispute about whether "parity" should be measured based on tonnage or number of vessels. The United States preferred tonnage, while the British preferred to count the fleet. To keep overall tonnage below the established limits, the British preferred to build light cruisers, but because light cruisers were essentially useless in battle against heavy cruisers, they wanted the United States and Japan to build the lighter variety as well. The United States had virtually no use for light cruisers and felt that as long as they stayed below the tonnage limit, they should be able to build as many heavy cruisers as they liked. It was a fundamental impasse.

In the interim between the failed Geneva talks of 1927 and the London Naval Treaty of 1930, several key compromises were worked out between the negotiating parties. The United States agreed to restrict its total number of heavy cruisers to 18, and build the remainder of its tonnage allowance in light cruisers. Japan gained a higher ratio of 10:7 against the American and British light cruisers and destroyers, and maintained the 10:6 ratios in heavy cruisers. The maximum armament allowed for subsequent light cruisers was set at 6-inch guns and maximum displacement 10,000 tons.

1930 - London Naval Conference

At the London Naval Conference of 1930, as in 1927, Japan insisted that the ratio for auxiliary vessels be increased to 10:10:7, rather than maintaining the 5:5:3 ratio. If the United States was to have 18 heavy cruisers, the latter ratio placed the Japanese limit at 10 cruisers. The other key issue of the 1930 conference was the maximum tonnage for light cruisers. The United States was adamantly opposed to any maximum lower than 10,000 tons. The other powers were far more willing to accept the British maximum of 7,000 tons. The treaty set maximum tonnage for cruisers at 339,000 tons for Great Britain, 323,500 tons for the United States, and 208,850 tons for Japan. The maximum numbers of heavy cruisers were set at 18 for America, 15 for Great Britain, and 12 for Japan.

The London treaty of 1930 subdivided cruisers into class A Heavy Cruisers (CA) with guns of over 6.1 inches calibre and type B Light Cruisers (CL), those with guns of 6.1 inches of less. It also allocated tonnage quotas. In 1926, construction had begun in the US on a new group of light cruisers, armed with eight-inch guns instead of the six-inch or smaller weapons carried by the existing CLs. Eight of these were completed between late 1929 and early 1931 as CL-24 through CL-31. At the beginning of July 1931, these eight ships were redesignated as "heavy cruisers" (CA), based on warship classifications established by the previous year's London Naval Treaty, but their hull numbers were not changed. These were simply a continuation of the same ships' previous light cruiser numbers and were not part of the earlier "ACR"/CA series, which became extinct with the scuttling of the old USS Rochester (CA-2) on Christmas Eve 1941, soon after the outbreak of the Pacific War.

1935 - London Naval Conference

The 1930 London Naval Treaty had specified that in 1935 another naval conference should be held between the parties. As talks began, a clear delineation became apparent with the Anglo-American parties aligning against Japan's demands for full parity. Japan walked out of the talks in 1936, leaving the United States, Great Britain, and France as the only signatories of the 1936 Treaty.

The six-year building holiday in the Second London Naval Treaty of 1936 applied to light cruisers exceeding 8,000 tons. Great Britain, France, and the United States signed an agreement declaring a six-year holiday on building large light cruisers in the 8,000 to 10,000 ton range. That final decision marked the end to the decade-long controversy over cruisers.

The failure of Japan to abide by the Treaty's qualitative restrictions in building programs led the signatory powers to invoke the escape clauses in the Treaty. By 1938 the 1936 Treaty was effectively no longer in effect and, since the 1930 Treaty had lapsed in 1936, naval limitations of any kind no longer existed. By 1938 Hitler and Mussolini were firmly in power and headed on a direct course for war in Europe. In the East, the steadily growing threat of Japanese Imperialism loomed larger with each passing month. It is into this world that the United States emerged from the naval limitations treaties, and began its steady slide into the global conflict soon to erupt across the globe.