In 1898, before any of Fort Terry's batteries were completed, the Spanish–American War broke out. It was feared the Spanish fleet would bombard the US east coast. A number of weapons were purchased from the UK and hastily mounted to give the nascent fort system some modern armament. By March 1898 a 4.7 inch/45 caliber gun was mounted at Battery Kelly under this program. It was later transferred to the Sandy Hook Proving Ground in New Jersey, possibly in 1903. A pair of emplacements for modern 8-inch M1888 guns on modified 1870s-era Rodman carriages were also built at nearby Fort Tyler, but these seem to have not been armed.