In the early 1890's, Tregantle and the other forts facing seaward were equipped with heavy shore batteries to improve the coastal defences. Tregantle's complement of four 9 inch marine-type guns was set in reinforced emplacements of concrete and red brick and mounted on swivelling platforms at tregantle Down Battery a short distance east of the fort, where they were able to cover an arc of fire across the wide expanse of Whitsand Bay.