The treaty was seen as an extension of the conditions agreed in the
Washington Naval Treaty, an effort to prevent a naval
arms race after
World War I. The conference was a revival of the efforts that had gone into the 1927
Geneva Naval Conference at which the various negotiators had been unable to reach agreement because of bad feelings between the British and the American governments. The problem may have initially arisen from discussions held between US President President
Herbert Hoover and UK Prime Minister
Ramsay MacDonald at
Rapidan Camp in 1929, but a range of factors affected tensions, which were exacerbated by the other nations at the conference. Under the treaty, the
standard displacement of submarines was restricted to 2,000 tons, with each major power being allowed to keep three submarines of up to 2,800 tons except that France was allowed to keep one. The submarine gun caliber was also restricted for the first time to with one exception, an already-constructed French submarine being allowed to retain guns. That put an end to the 'big-gun' submarine concept pioneered by the British
M class and the French
Surcouf. Per the terms of the treaty, Britain, the United States, and Japan reduced their number of capital ships, Japan by one, the United States by three, and Britain by five. Some were scrapped and others converted to auxiliary or training ships. All of these had been launched prior to WWI, and had smaller guns than most of the ships which were retained. The treaty also established a distinction between cruisers armed with guns up to ("
light cruisers" in unofficial parlance) from those with guns up to ("
heavy cruisers"). The number of heavy cruisers was limited: Britain was permitted 15 with a total tonnage of 147,000, the Americans were permitted 18, totalling 180,000, and the Japanese were permitted 12, totalling 108,400 tons. For light cruisers, no numbers were specified but tonnage limits were 143,500 tons for the Americans, 192,200 tons for the British, and 100,450 tons for the Japanese. Destroyer tonnage was also limited, with destroyers being defined as ships of less than 1,850 tons and guns up to . The Americans and the British were permitted up to 150,000 tons and Japan 105,500 tons. Article 22 relating to submarine warfare declared
international law applied to them as to surface vessels. Also, merchant vessels that demonstrated "persistent refusal to stop" or "active resistance" could be sunk without the ship's crew and passengers being first delivered to a "place of safety". Article 8 outlined smaller surface combatants. Ships between 600 and 2,000 tons, with guns not exceeding with a maximum of four gun mounts above without torpedo armament and up to , were exempt from tonnage limitations. The maximum specifications were designed around the French
Bougainville-class avisos, which were in construction at the time. Warships under 600 tons were also completely exempt. That led to creative attempts to use the unlimited nature of the exemption with the Italian
Spica-class torpedo boats, Japanese
Chidori-class torpedo boats, French
La Melpomène-class torpedo boats and British
Kingfisher-class sloops. ==Aftermath==