 Its arc of fire would overlap that of Grain Fort and Grain Tower (and later Grain Wing Battery and Dummy Battery) on the other side of the Medway on the Isle of Grain.Construction began in February 1861 and continued until the last of its shielding was installed in June 1872, by which time about half of the guns were already in place.The new fort took the form of a semi-circular structure, one of only two built in the 1860s fortification programme (the other being Picklecombe Fort in Cornwall).