On February 19th, Brigadier General Quincy A. Gillmore landed on Big Tybee Island to direct siege operations against Fort Pulaski.  The island was garrisoned by the 46th New York Infantry and 7th Connecticut Infantry regiments, five companies of the 8th Maine Infantry regiment, two companies of the 3rd Rhode Island Artillery, and Company A, Corps of Engineers.
          Gillmore’s original plan was to construct batteries closer to the eastern end of the island near the Tybee Island Lighthouse.  However, subordinates quickly persuaded him to abandon this plan and move the construction site to Goat Point on the western end of the island.  Goat Point was the closest area on the island to Fort Pulaski.  Additional batteries were to be built stretching to the east along the shore.
          Work began on February 21st.  Ships would deliver the ordnance onto the beach, where soldiers from the infantry regiments had to drag them ashore.  Once assembled, they dragged the guns on skids along the beach to the batter sites.  All of the work was done at night, observing strict light and noise discipline.  The sites of the batteries were camouflaged every night with brush to conceal the construction.  Soldiers and officers were forbidden from exposing themselves during the day.  The Confederate garrison at Fort Pulaski knew something was happening, but had no idea of the magnitude of the operation.
          Union forces constructed a small mortar battery on Long Island to the west of Cockspur Island, with the intention of lobbing shells into the fort from the rear.  However, the Confederates discovered the battery on April 9th and disabled it.  The Federal garrison had abandoned it during the day to avoid isolation, unfortunately relying on concealment to avoid its detection.
          Everything was ready by the morning of April 10th.  Large mortars would bombard the fort, caving in the roof and making the barbette guns untenable.  The smoothbore and rifled cannons would chip away at the walls of the fort, unseating the barbette guns and destroying the casemates.  General Gillmore did not put much faith in the rifled artillery, but instead was relying on the preponderance of mortars to do the heavy work.