I found a chunk:According to the April 30, 1861 report of Brigadier General Johnson K. Duncan regarding the surrender of Forts Jackson and Saint Philip, "the five 10 inch Sea-Coast mortars recently obtained from Pensacola on the evacuation of that place" were in Louisiana prior to the bombardment of the forts. They were not in place, however, with mention made of the need for construction of emplacement and magazines.
Duncan also mentions knowledge of the weight of fire expected, "In consequence also of the character of the expected attack by heavy mortars, it was deemed advisable to cover all the main magazines at both the forts with sand bags to a considerable depth, to protect them against vertical fire."
The fleet of Farragut and Porter crossed into the Mississippi on March 27.