The instructions were to peacefully reprovision the fort. If the ships were opposed and forces on the ground did not allow peaceful passage of the supply ships there was an authorization to use force. There was an instruction to use force. It wasn't a suggestion.
"Should the authorities at Charleston, however, refuse to permit or attempt to prevent the vessel or vessels having supplies on board from entering the harbor, or from peaceably proceeding to Fort Sumter, you will protect the transports or boats of the expedition in the object of their mission-disposing of your force in such manner as to open the way for their ingress and afford, so far as practicable, security to the men and boats, and repelling by force, if necessary, all obstructions towards provisioning the fort and re-enforcing it; for in case of resistance to the peaceable primary object of the expedition a re-enforcement of the garrison will also be attempted. "
The Statement from Simon Cameron was more direct.
" WAR DEPARTMENT, Washington, April 4, 1861.Captain G. V. FOX, Washington, D. C.:
SIR: It having been decided to succor Fort Sumter you have been selected for this important duty. Accordingly you will take charge of the transports in New York having the troops and supplies on board to the entrance of Charleston Harbor, and endeavor, in the first instance, to deliver the subsistence. If you are opposed in this you are directed to report the fact to the senior naval officer of the harbor, who will be instructed by the Secretary of the Navy to use his entire force to open a passage, when you will, if possible, effect an entrance and place both troops and supplies in Fort Sumter.
I am, sir, very respectfully, your obedient servant,
SIMON CAMERON,
Secretary of War.
For that mater, David Porter said in his memoirs that if those ships had tried to do something, they would have all been sunk.
“to use his entire force to open a passage, when you will, if possible, effect an entrance and place both troops and supplies in Fort Sumter.’
This action was only authorized if the Charleston forces resisted the landing of provisions (only) to the fort.
SECRETARY WELLES INSTRUCTIONS TO CAPT. MERCER OF THE POWHATAN.
Capt. Samuel Mercer, commanding U.S. Steamer Powhatan, New-York:
SIR: The United States steamers Powhatan, Pocahontas, Pawnee, and Harriet Lane will compose a naval force under your command to be sent to the vicinity of Charleston, S.C., for the purpose of aiding in carrying out the objects of an expedition, of which the War Department has charge.
The primary object of the expedition is to provision Fort Sumter, for which purpose the War Department will furnish the necessary transports. Should the authorities of Charleston permit the fort to be supplied, no further particular service will be required of the force under your command, and, after being satisfied that supplies have been received at the fort, the Powhatan, Pocahontas and Harriet Lane will return to New York, and the Pawnee to Washington.
Should the authorities at Charleston, however, refuse to permit or attempt to prevent the vessel or vessels having supplies on board from entering the harbor or from peaceably proceeding to Fort Sumter, you will protect the transports or boats of the expedition in the object of this mission — disposing of your force in such a manner as to open the way for their ingress, and afford, so far as practicable, security to the men and boats, and repelling, by force if necessary, all obstructions to provisioning the fort and reinforcing it; for in case of resistance to the peaceable primary object of the expedition, a reinforcement of the garrison will also be attempted. These purposes will be under the supervision of the War Department, which has charge of the expedition. The expedition has been intrusted to Capt. G.V. FOX, with whom you will put yourself in communication, and cooperate with him to accomplish and carry into effect its object.
You will leave New-York with the Powhatan in time to be off Charleston bar, ten miles distant from and due east of the lighthouse, on the morning of the 11th inst., there to await the arrival of the transport or transports with troops and stores. The Pawnee and Pocahontas will be ordered to join you there at the time mentioned, and also the Harriet Lane, which latter vessel has been placed under the control of this Department for this service.
On the termination of the expedition, whether it be peaceable or otherwise, the several vessels under your command will return to the respective ports as above directed, unless some unforeseen circumstances shall prevent. I am, &c., &c.
(Signed,) GIDEON WELLES,
Secretary of the Navy.
As in Cameron’s orders to Fox, the naval vessels are authorized to use force only if the Charleston authorities
resist the landing of food to the Fort. If The Charleston authorities allow the provisioning of the fort, the ships are to return to their home ports. If they resist the provisioning attempt the ships are authorized to us force, as needed, to land food, munitions and reinforcements.
Nowhere in the written orders to Fox or the captains of the warships are they instructed to fire indiscriminately on Charleston or any installations surrounding the city.