Editing Courageous-class aircraft carrier (section)

== Careers as battlecruisers ==
{{Main|Courageous-class battlecruiser}}

[[File:HMS Glorious (1917) profile drawing.png|thumb|left|''Glorious'' as a battlecruiser]]
The first two ships of the class, ''Courageous'' and ''Glorious'', spent the First World War on [[North Sea]] patrols, climaxing in the [[Second Battle of Heligoland Bight]] in November 1917. Their half-sister ''Furious'' was designed with a pair of {{convert|18|in|0|adj=on}} guns—as opposed to four {{convert|15|in|0|adj=on}}—but was modified while being built to hold a flying-off deck and [[hangar]] in lieu of her forward [[gun turret|turret]] and [[barbette]]. She made some patrols in the North Sea before her rear turret was removed and another flight deck added. Her aircraft attacked [[Zeppelin]] sheds during the [[Tondern raid]] in July 1918.<ref>Roberts, p. 123</ref>

All three ships were reduced to reserve after the war. The Washington Naval Treaty of 1922 limited the signatory nations to a set amount of capital ship tonnage; all ships in excess of this figure had to be scrapped. Up to {{convert|66000|LT|t|lk=on}} of existing ships could be converted into aircraft carriers, and the Royal Navy decided to use the ''Courageous''-class ships due to their high speed. Each ship was reconstructed with a flight deck during the 1920s.<ref>Friedman, p. 97</ref>