Scout cruiser

HMS Sentinel, the first scout cruiser

A scout cruiser was a type of warship of the early 20th Century, which were smaller, faster, more lightly armed and armoured than protected cruisers or light cruisers, but larger than contemporary destroyers. Intended for fleet scouting duties and acting as a flotilla leader, a scout cruiser was typically armed with six to ten destroyer-type guns of 3-inch (76mm) to 4.7-inch (120mm) calibre, plus two to four torpedo tubes.

The British were the first to operate scout cruisers, with the Royal Navy acquired 15 ships divided into two distinct groups - the eight vessels all ordered under the 1903 Programme, and the seven later, heavier-armed vessels ordered under the 1907-1910 Programmes. All these ships served in World War I, when the advent of better machinery and larger, faster destroyers and light cruisers had already made them obsolete.

The other major operator of scout cruisers was Italy. With no conventional protected cruisers or light cruisers planned between 1900 and 1928, the Regia Marina instead operated a number of scout cruisers (esploratori) from 1912 onwards. Ranging in size from enlarged destroyers to substantial, light cruiser-like ships, these esploratori were also given secondary capabilities as fast minelayers. Later esploratori, such as the Leone class, carried extremely heavy armament for their modest size, capable of outgunning any destroyer of the early 1920s. However, by 1938 the surviving esploratori were re-rated as destroyers.

Scout cruiser designs

Austro-Hungarian Navy

Brazilian Navy

Bahia class

Peruvian Navy

Almirante Grau class

Regia Marina

Note: this list includes the ‘super-destroyers’ rated as scouts (esploratori) by Italy.

Agordat class - protected cruisers, rated as esploratori from 1914 to 1921
Quarto
Nino Bixio class
Alessandro Poerio class - included Cesare Rossarol
Mirabello class
Aquila class
Leone class
Capitani Romani class - originally classified esploratori oceanici (ocean scouts), then re-rated light cruisers

Royal Navy

United States Navy

Chester class - later re-rated as light cruisers
The first three Omaha class cruisers were also designated "scout cruisers" (CS) when ordered, but before any were launched the Navy revised its classification system in 1920 and they and the Chesters became "light cruisers" (CL).