 These smaller caliber batteries were completed in 1906.The fort, which had previously consisted of a battery of muzzle-loading cannon atop the northeastern head of the island, was now equipped with the latest in coast artillery, as part of nationwide improvements in coastal defense capabilities recommended by the Endicott Board.Although the gun batteries were completed in 1906, construction at the fort would continue through the 1920s, eventually creating a total of seven new batteries of 3-inch, 4.7-inch, and 10-inch guns along three sides of the island, extensive facilities for deploying and recovering the tethered mines which filled the nearby channels, and barracks space for over 1,000 members of the Coast Artillery who served at the fort.