An American four-stacker of about 1,310 tons standard shows the scale of the large First World War inventories affected by the replacement rules. Destroyers were limited to 1,850 tons and guns no larger than 5.1 inches, while ships laid down after 1920 received a sixteen-year service life. Pre-1921 ships could be replaced after twelve years, encouraging the renewal of the American four-stackers and British V and W classes. Replacing them in one concentrated programme would create another large replacement bill later. Britain and the United States each received 150,000 tons and Japan 105,500 tons. The 16-percent leader allowance shaped flotilla organization because the larger ships consumed tonnage faster than ordinary destroyers.
Chapter · 12:00-15:35
The London Treaty's destroyer rules
The 1930 treaty defined destroyers, set replacement ages, capped national tonnage, and reserved only 16 percent of that allowance for larger leaders.