Ship Cover for the Emerald class composite screw corvettes HMS Emerald (1876), HMS Garnet (1877), HMS Opal [ex-Magicienne] (1875), HMS Ruby (1876), HMS Tourmaline (1875) and HMS Turquoise (1876). The documentation begins during the planning stages for this class in about February 1873 and the last papers relate to the use of Garnet, Ruby and Tourmaline as coal hulks in November 1913. Subjects covered by the documents include the preliminary and final specifications of weights and dimensions, correspondence relating to contractors' tenders, stability, masting, stores, ammunition, armament and crew allocation, engine and propulsion data and reports of comparative trials between this class and the preceding Amethyst class.