By 1851, the United States had started preparing detailed plans for the three new forts and batteries. The Pacific Army of Engineers arrived at Alcatraz in the winter of 1853, and began to finalize specific plans for the development. Construction at Alcatraz would commence in 1854, with a $500,000 appropriation from the U.S. Congress. In his first report to Washington, Major John L. Smith gave a description of his initial surveys, writing: “The island of Alcatraces is a mass of rock with a very thin layer crust of soil and bird manure on the surface.” Construction at Alcatraz would commence only months later. First Lieutenant Zealous Bates Tower had been assigned to manage the building of the fortress at Alcatraz, along with his assistant, Second Lieutenant Frederick Prime. The topography of fine-grained sandstone proved to offer more challenges than was originally predicted. Tower would report:
The island is rougher than I anticipated, very rough, steep, and broken on the Eastern Portion of the North West Battery and where the three gun battery is designed to be placed... The sandstone composing the island is very friable; even where hardened on the surface it can be cut with a hatchet. Wrought iron spikes can be driven into the Rock without much trouble... During the month of October, I expect to finish all of the temporary buildings required for the rapid progress of the work, including water tanks, to build the wharf, to prepare the road at least as far as the guardhouse and to make good progress on the ditch of the South Battery.
A military diagram created in September of 1855, illustrating the plans for the fortification and construction in progress. First Lieutenant Zealous Bates Tower supervised the building of the fort in 1854, and later reported that the terrain of Alcatraz was much rougher than he had expected.
An 1870 Eadweard Muybridge photograph of “Pirate’s Cove,” which is located on the western side of Alcatraz. This photograph illustrates the island’s primitive terrain, which discouraged boat landings. Much of the current geographical contours are the result of blasting and reshaping efforts by the early Army Engineers.
The task of converting the Rockinto a sound fortress entailed a series of hardships for labor crews. On July 9, 1857, when three men were excavating the cliff between the wharf and the guardhouse, they unleashed a massive landslide. Two of the men, Daniel Pewter and Jacob Unger, were fatally trapped under the loose debris while the other worker escaped with serious injuries. They would become the first ever fatalities on Alcatraz. During the construction, it was found that the Rock mineral proved to be too frail to be used in the fortification and this necessitated the importation of stone from as far away as China. Granite that was ordinarily used as ballast on ships was also apparently employed in the construction. Masons used a high grade of brick, set in heavy concrete forms to create a dense shield of armor against enemy ammunitions. Construction crews also dug well-concealed tunnels that offered safe storage for cannon powder and other munitions . There were specialized furnaces designed to heat incendiary shells, which would be fatal toward fire-prone wooden ship hulls.
A communication tunnel that was excavated in 1873. The 180-foot tunnel was used as a passageway between two batteries by soldiers during the military era. The Bureau of Prisons sealed the tunnel in 1936 to alleviate the risk of inmates using this passage as an escape route.
A 19th-century woodcut engraving from William Cullen Bryant's 1872 publication Picturesque America, showing an early portrayal of Alcatraz as a military fortress.
Second Lieutenant James Birdseye McPherson took command of the fortification construction in January of 1858. In personal letters he implied regret for his post assignment, indicating that the conditions on Alcatraz were cold and miserable. Nevertheless, he proved to be an effective commander at the fort. He would later advance through the ranks, and was eventually killed during the Civil War in the Battle of Atlanta.
On December 31, 1857, 2 ndLt. James Birdseye McPherson was assigned to Alcatraz to continue supervision of the final construction activities. McPherson lived on the island full-time and in several letters he implied that he disliked his assignment. In one of these he wrote:
I often think of my position one year ago, and instinctively draw a comparison between it and my present one. Candor compels me to state that in everything appertaining to the social amenities of life the “Pea Patch” [Fort Delaware] is preferable to Alcatraz — though I am determined to make the best of the matter, looking forward joyfully to the time when I can return to the Atlantic States.
Regardless of his personal bias, McPherson was a dedicated commander and effective taskmaster. He kept his men focused on their orders, and accomplished his objectives at Fort Alcatraz. During an inspection report filed in January of 1859, J.K.F. Mansfield wrote the following:
I this afternoon inspected the fortifications on Alcatrazes Island in this harbor, and have to report the result to the general chief as follows:
This work has been under the superintendence of 2nd Lieut. James B. McPherson of the Corps of Engineers since the 1 stof January 1858 when he relieved Brevet Major Z.B. Tower of the Corps of Engineers who commenced this work. This work from the beginning has been extremely well conducted, and managed by most faithful and meritorious officers. The progress has been great under the difficulties to be encountered in a new country, at the time the work was commenced.
At first it was difficult to obtain suitable building materials. New stone is had at various places. Excellent granite comes from Folsom on the American River, for both coping and walls. Granite for coping is had at Monterey. Blue calcarious hard stone is had in this harbor from Angel Island. Brick is in the greatest abundance, and excellent quality from Sacramento. Lime from Diablo via San Joaquin River. Water from Sausalito on the Main, and cement from New York, and all at constructively reasonable rates.
McPherson left Alcatraz on August 1, 1861, and died following an attack by the Confederate Army during the Battle of Atlantain July of 1864.
After several years of laborious construction and several armament expansions, Alcatraz was established as the United States’ western symbol of military strength. The fort boasted over a half mile of masonry walls made of dense brick and sandstone, which surrounded the island, and in some sections stood over thirty feet tall. The new military fortress featured long-range iron cannons and four massive 36,000-pound, 15-inch Rodman guns, which were capable of sinking mammoth hostile ships three miles away. The guns of Alcatraz could fire 6,949 pounds of iron shot in one barrage. At the island’s peak of military supremacy, which came at the end of the Civil War, the fortress had 129 cannons lining the perimeter, capable of firing fifteen-inch cannon balls weighing over four hundred pounds, to a distance of nearly three miles.