Powder and refuge was in the 'bombproofs', compartments dug out in the sand beneath the walls. The Union tried another idea. They loaded up a ship with 250 tons of explosives and then in a daring attempt drove it close to the fort and set it off. The concussion and blast should have leveled the fort, the sand fort. Nothing, just a real big bang.
Sand just absorbs concussion and shock.
It finally took 2000 soldiers and 3000 marines to overrun the fort at the river entrance. There's a ferry here, too, to get across the river to Southport. He told me some things he saw as a kid when he and his father walked on the beach. His granddaddy is this same Captain Bolles.