in a particularly strategic location as it commanded river bends at which ships would have to slow down, making them more vulnerable. Construction The third and final iteration of Shornemead Fort was constructed between 1861 and 1870 at an estimated cost of £211,063. The fort and its counterparts at Coalhouse Point and Cliffe were designed, except for their ironwork, by Captain Siborne of the Royal Engineers. The iron and steel shields of their casemates were developed by Captain English and Lieutenant English of the Royal Engineers. It was substantially larger than its predecessor, replacing the vulnerable open emplacements with immensely strong casemates capable of resisting direct artillery fire. They were over thick, with layers of steel and wood faced with granite. The original plans envisaged the roof of the fort being used to emplace fourteen guns behind shields and a masonry parapet. Two pivot guns and twenty other guns would be housed at ground level within casemates. However, subsidence caused by the marshy ground was again a problem for the fort builders. The design could not be realised in its original form and it underwent substantial changes in 1867, part-way through construction. In the final design, the plan to put guns on the fort's roof were abandoned. Instead, eleven casemates were placed in an arc on one side of the D-shaped fort, pointing downriver towards Lower Hope Point. An open battery stood at the west end of the casemates, mounting three guns that pointed upriver toward Gravesend and Tilbury. This was to enable artillery support for the older forts at those two towns, which were now relegated to the second line of defence. A single-storey defensible barracks built from Kentish Ragstone stood at the rear of the fort. It was equipped with loopholes so that the garrison could fight off an attack from the landward side. Three caponiers protected the perimeter and an open parade ground occupied the centre of the fort. A ditch originally lay in front of the casemates and open battery but was filled in during the 1880s. The magazines underneath the casemates and open battery consisted of a line of storerooms for shells and cartridges, linked by a lighting passage at the rear and an ammunition passage at the front. Operational history Shornemead Fort was initially equipped with eleven 11-inch rifled muzzle loaders (RMLs) in casemates, with a range of , plus another three 9-inch RMLs