Restricted minimum service periods of warships before replacement was allowed according to the Second London Naval treaty of 1936

The Second Naval Treaty ratified by the United Kingdom, USA and France in 1936 was a result of the expiration of the Washington Naval Treaty of 6 February 1922 and the First London Naval Treaty of 22 April 1930. The new treaty to be enter in force on 29 July 1937 and to expire on 31 December 1942 and was a renewed effort to prevent a naval arms race. Instead to the earlier treaties refused Japan and Italy to sign the new treaty.

One of the restrictions was to allow replacement not earlier as when ships were ‘over age’ or a certain number of years after completion. Capital ships 26 years, aircraft carriers 20 years. Light surface vessels subcategories ‘a’ and ‘b’ if laid down before 1 January 1920 16 years and if laid down after 31 December 1929 20 years, light surface vessels sub-category ‘c ’16 years and finally submarines 13 years.

Light surface vessels other than aircraft carriers, minor war vessels or auxiliary vessels with a displacement between 100 tons/102 metric tons-10.000 tons/10.160 metric tons and with a main armament of maximum 20,3cm/8” guns. There were 3 sub categories:

a. with a main armament with a maximum of 15,5cm/6.1” guns;

b. without a main armament with a maximum of 15,5cm/6.1” guns and with a standard displacement of minimum 3.000 tons/3.048 metric tons;

c. without a main armament with a maximum of 15,5cm/6.1” guns and with a standard displacement of maximum 3.000 tons/3.048 metric tons.