There was also the fact that Ft. Sumter, a three story fortification, would control Ft. Moultrie if seized by secessionists. Anderson, without a full garrison for any one fort, could not afford to further split his force to guard Castle Pinckney, Fort Sumpter and Fort Moultrie. Being completely surrounded by water and with its lower tier embrasure bricked up, Fort Sumpter was the most defensible with the small garrison at hand.