Unprotected cruiser

An unprotected cruiser was a type of naval warship in use during the late Victorian or pre-dreadnought era (about 1880 to 1905). The name was meant to distinguish these ships from “protected cruisers” which had become accepted in the 1880s. A protected cruiser did not have side armor on its hull like a battleship or “armored cruiser” but had only a curved armored deck built inside the ship – like an internal turtle shell – which prevented enemy fire penetrating through the ship down into the most critical areas such as machinery, boilers, or ammunition storage. An unprotected cruiser of course lacked even this level of internal protection. The definitions had some gray areas because individual ships could be built with a protective deck that did not cover more than a small area of the ship, or was so thin as to be of little value (the same was true of the side armor on some armored cruisers). An unprotected cruiser was generally cheaper and less effective than a protected cruiser, while a protected cruiser was generally cheaper and less effective than an armored cruiser (with some exceptions in each case).

Unprotected cruisers included medium-sized ships such as the Spanish Reina Cristina and Chinese Kai Che down to smaller ships of about 1,000 tons. A small unprotected cruiser was little different from a large gunboat (for instance, at the Battle of Manila in 1898 the American Concord was larger than the Spanish unprotected cruisers of the Velasco class, and was equivalent to a small British protected cruiser, however the US Navy classified Concord as only a gunboat.) Such ships could be known by alternate names depending on the preference of each navy. For instance, the British Royal Navy tended to refer to larger gunboats/small cruisers as “sloops”.

The designation “unprotected” made sense only after the development of protected cruisers in the 1880s. Many ships designed earlier had essentially the same features and size range; for instance, the Spanish Castilla, the French Lapérouse and the Dutch Atjeh-class ships were also to be called unprotected cruisers. Steel-hulled cruisers had been preceded by iron-hulled (but not armored) ships and composite (iron and wood)-hulled ships, which were originally termed cruisers, frigates, or corvettes. Most of these ships retained sailing rig and were useful for colonial duties, where dockyards and coal supplies were often inadequate. Some of these older ships were fairly large, for instance HMS Shah.

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