Fort Fincastle is most a most unusual battery, built on a high point overlooking Nassau Harbour. The actual battery is tear drop shaped with the semi-circular gun platform facing towards the harbour. The rear tapers down to a sharp point. The magazine is located under cover, behind the gun platform. Built in 1793 the battery was armed with two 32-pdr SB guns, two 12-pdr SB guns and one 8-inch howitzer. In 1859 the Battery was armed with three 18-pdr guns and two 10-inch Howitzer. These guns still remain on site.
In 1859 there were plans to build counter scarp galleries to help protect the battery from land attack. It is not know if these were ever built. There were also plans to replace the three 18-pdr guns with three 68-pdr guns, but this was never done. (TNA WO 55/1550/12)