Square @-@ shaped Fort Sullivan consisted only of the completed seaward wall , with walls made from palmetto logs 20 feet ( 6 @.@ 1 m ) high and 16 feet ( 4 @.@ 9 m ) wide . The walls were filled with sand , and rose 10 feet ( 3 @.@ 0 m ) above the wooden platforms on which the artillery were mounted . A hastily erected palisade of thick planks helped guard the powder magazine and unfinished northern walls . An assortment of 31 cannon , ranging from 9- and 12 @-@ pounders to a few British 18 @-@ pounders and French 26 @-@ pounders , dotted the front and rear walls . General Lee , when he had seen its unfinished state , had recommended abandoning the fort , calling it a " slaughter pen " . President Rutledge refused , and specifically ordered Colonel Moultrie to " obey [ Lee ] in everything , except in leaving Fort Sullivan " . Moultrie 's delaying tactics so angered Lee that he decided on June 27 that he would replace Moultrie ; the battle began the next day before he could do so . Lee did make plans for an orderly retreat to Haddrell 's Point .