The fort was armed with three 68-pounder guns and two 32-pounder guns, each capable of firing up to 1600 yards, and the two underground magazines were designed to house 126 barrels of gunpowder. The fort was planned to accommodate two infantry officers, one master gunner, and 42 NCO's and privates, in its internal barracks, and a further 30 NCO's and privates could also be accommodated in a small enclosure or hut, on the north side, just outside the fort.
Two magazines at the rear of each end of the ramparts were sunk below ground level and would have stored 126 wooden barrels of gunpowder. Adjacent to each magazine chamber would have been a small passage way where the fuses were prepared and the charges bagged up, when the charges were ready they would then have been carried by hand to the stone recess magazines situated next to the guns on the terreplein and stored there until required. When built and garrisoned the fort was then considered as being self-sufficient as it would hold enough water and supplies to withstand a siege until support troops were able to arrive.
In 1870, just sixteen years after the fort was completed, a survey was started by Edward Cardwell, Secretary of State for War. The objectives of this survey were to improve the efficiency of the army by making reductions in unnecessary expenditure. Three years later in 1873 the survey had been finished and it was decided that both Littlehampton fort and Shoreham could no longer keep up with the technology of the arms, as by that time the guns design were much bigger and heavier and the ramparts of the forts were not suitable, and from that time both forts were not upgraded but were used in their current design until 1906 when they were taken out of action or decommissioned.
These were all my findings from research, Andy Orpin is now furthering this research and attempting to do a similar restoration project to read more about it please visit Littlehamptons Fort's website.