I ["Fleet Admiral" Fox] proposed to anchor three small men-of-war off the entrance to the Swash Channel as a safe base of operations against any naval attack from the enemy, the soldiers and provisions to be carried to the Charleston bar in the Collins steamer Baltic, all the provisions and munitions to be put up in portable packages easily handled by one man, the Baltic to carry 300 extra sailors and a sufficient number of armed launches to land all the troops at Fort Sumter in one night.
On paper, the "fighting sailors" were to have supplies [remaining shipboard] for one month. The soldiers were to be landed with supplies for a year. All the provisions and munitions were to be put in portable packages easily handled by one man. One man cannot carry a year's worth of his own provisions. The 300 "fighting sailors" were needed to act as pack mules to carry the hundreds of portable packages of provisions, each designed to be handled by one man.
In reality, nobody was deluded enough to make the attempt. They could have landed a thousand soldiers with a hundred years supplies and it would have made no difference. The fort was reduced to a smoldering ruin in two days. The only thing they really would have needed was two days rations and body bags.
As a military mission, it was impossible as all the army officers had said. Even had the purported mission, such as it was, succeeded in doing what it purported to do, the soldiers reaching the fort would have been surrounded by the batteries observed on April 14 by Commander Rowan:
April 14. ... At 1 p. m. observed the American flag flying over Fort Sumter. At 2 a salute of fifty guns was fired and the flag was then hauled down. At 4 p. m., the so called Confederate flag, similar to the one flying over Fort Moultrie during the attack on Major Anderson, was hoisted on Fort Sumter amid a general fire from all the forts and batteries. During the firing in honor of what is called the Confederate flag on Fort Sumter, took the bearings of the different batteries on Morris Island and Sullivan's Island, several of which had hitherto been unnoticed.
North side Sullivan's Island:
Battery bearing N.
Battery bearing N. W. by N.
Battery bearing N. W.
Battery bearing N. W. 1/2 W. Cumming's Point, W. 1/2 S.
Fort Sumter, W. 3/4 N. Extreme front of Morris Island:
Battery bearing S. W. 1/2 W.
Battery bearing S. W. by W. 1/4 W.
Battery bearing S. W. by W. 1/2 W.
Battery bearing W. S. W. 1/2 W.
Battery bearing W. S. W.
On Page 253, Commander Rowan had noted that "Fort Moultrie, Cumming's Point, Fort Johnson, and the sand and floating batteries were all playing on Fort Sumter."
On Page 252, Commander Gillis, the Senior Officer Present, noted, "Found the fort a complete wreck, the fire not yet all extinguished. Its shattered battlements, its tottering walls, presented the appearance of an old ruin."
The purported mission was to take what they could carry on their backs to an indefensible position that could barely hold out 48 hours before being demolished.
They were to be in a fort on a man-made island in the harbor. Clearly, they were to occupy the low ground and have no means of retreat or movement. Unless the "portable packages easily handled by one man" included portable rocket launchers, it is unclear how the additional men could have added to the defensive capability of the fort. The fort was designed to shoot at and sink ships. It could not sink the shore batteries.
Groceries were not needed. Adding soldiers could only add targets and start the shelling.