Scale 1:96. Plan shows the inboard profile, upper and main deck design drawing for a unnamed 115ft twin screw mortar vessel (1891). The plan bears the signature of Sir William Henry White [Director of Naval of Construction 1885-1902]. Annotations have been made on the plan. The title of the plan is "Sketch Design of a Twin screw vessel to carry on 18 Ton R.M.L. (Rifled Muzzle Loader) on a high angle mounting".