From scout cruiser to modern light cruiser

Design work began in 1911, and the class moved into construction in 1912 before the first launches in 1913. The Arethusas were the Royal Navy's overdue answer to scout cruisers that were too slow for their own safety. Because a small cruiser could not rely on heavy protection, speed was especially important. The target was 30 knots so they could lead destroyers in combat, although the completed ships managed about 28.5 knots. Oil firing and steam turbines made that performance possible. The comparison with faster British dreadnoughts exposes how long the service had tolerated a mismatch between the scout cruiser's mission and its machinery.