Until a rocket-assisted axe was invented, of course.
We arrived off Charleston the 12th instant, at 3 a.m., and found only the Harriet Lane. Weather during the whole trine a gale. At 7. a.m. the Pawnee arrived, and, according to his orders, Captain Rowan anchored twelve miles east of the light, to await the arrival of the Powhatan. I stood in with the Baltic to execute my orders by offering, in the first place, to carry provisions to Fort Sumter. Nearing the bar it was observed that war had commenced, and, therefore, the peaceful offer of provisions was void.
The Pawnee and Lane immediately anchored close to the bar, notwithstanding the heavy sea, and though neither tugs or Powhatan or Pocahontas had arrived, it was believed a couple of boats of provisions might be got in. The attempt was to be made in the morning, because the heavy sea and absence of the Powhatan's gunboats crippled the night movement. All night and the morning of the 13th instant it blew strong, with a heavy sea. The Baltic stood off and on, looking for the Powhatan, and in running in during the thick weather struck on Rattlesnake Shoal, but soon got off. The heavy sea, and not having the sailors (three hundred) asked for, rendered any attempt from the Baltic absurd. I only felt anxious to get in a few days' provisions to last the fort until the Powhatan's arrival. The Pawnee and Lane were both short of men, and were only intended to afford a base of operations whilst the tugs and three hundred sailors fought their way in.
This guy is saying the three hundred sailors were needed to ensure provisions making it to the fort. That means that they would've offered protection while ships were being unloaded, and they needed arms to cover the offloading of provisions.