 From this point Fort Glanville 's significance declined rapidly . Fort Largs was equipped in 1889 with two 6 inch breech @-@ loading disappearing guns which <unk> Glanville 's armament . The decline was also linked to changes in Port Adelaide 's maritime facilities and the consequent northward movement of anchored and berthed vessels . During the 1880s the Port River was deepened enabling large ships to sail up and berth , rather than the former practice of anchoring off @-@ shore . 
