On the morning of June 28 , Fort Sullivan was defended by Colonel Moultrie , commanding the 2nd South Carolina Regiment and a company of the 4th South Carolina Artillery , numbering 435 men . At around 9 : 00 am that morning , a British ship fired a signal gun indicating all was ready for the attack . Less than an hour later , nine warships had sailed into positions facing the fort . Thunder and Friendship anchored about 1 @.@ 5 miles ( 2 @.@ 4 km ) from the fort while Parker took Active , Bristol , Experiment and Solebay to a closer position about 400 yards ( 370 m ) from Sullivan 's Island , where they anchored facing broadside to the fort . Each of these ships began to fire upon the fort when it reached its position , and the defenders returned the fire . Although many of Thunder 's shots landed in or near the fort , they had little effect ; according to Moultrie , " We had a morass in the middle , that swallowed them up instantly , and those that fell in the sand in and about the fort , were immediately buried " . Thunder 's role in the action was also relatively short @-@ lived ; she had anchored too far away from the fort , and the overloading of her mortars with extra powder to increase their range eventually led to them breaking out of their mounts . Owing to shortage of gunpowder , Moultrie 's men were deliberate in the pace of their gunfire , and only a few officers actually aimed the cannons . They also fired in small volleys , four cannon at a time . One British observer wrote , " Their fire was surprisingly well served " and it was " slow , but decisive indeed ; they were very cool and took care not to fire except their guns were exceedingly well directed . "