[DiogenesLamp]

May be wrong about the extra boats on Powhatan. But the plan never called for the supply ship or the warships to enter Charleston Harbor. They were to be anchored about 4 miles from Sumter. That would have put the ships beyond the range of the Confederate gun batteries.

So how were they going to use "all the force" at their disposal to place both men and supplies into the fort?

Warships aren't much good if you don't actually use them.

[Bull Snipe]

That would have been up to the ranking captain on scene.
The plan was to send in provisions only. If that occurred, the mission was accomplished and the ships were to return to their ports. If not, the ships were authorized to use force to land not only provisions by munitions and two companies of artillerymen. Since the fort was being fired upon, the resupply mission was not attempted.