That's the point, though, you're saying it's common knowledge - but it's "common knowledge" that the British Army in the Victorian era was incompetent, and it clearly wasn't.
I've been citing specific examples of where naval PoDs (
Mississippi and
Louisiana, more commerce raiders drawing off more Union ships as per the OTL drawing off of ships) could make a big difference.
Here's a case of a Union vessel (Iroquois) attempting to break neutrality regulations to be informed of the departure of a Confederate on (Sumter):
"In the morning a French man-of-war arrived from Port Royal, the seat of government, only twelve miles distant. The Sumter had been there for the last two days. The Government, it is true, had refused to give her any of its coals, but had allowed her to come around to St. Pierre, where she readily obtained them from some merchants (English, I believe). " She evidently had been received with courtesy at the seat of Government, and this farce of the non-recognition of the Confederate flag is played out by both France and England in the most flagrant manner. " I now addressed a letter to the Governor, assuming him to be ignorant of the character of the Sumter, a copy of which I enclose, I also enclose a translation of his reply. The Department will observe that from the generous disposition of the Governor, the Sumter has the same privileges as this vessel. " The captain of the French war- steamer also addressed me a letter, saying he was directed by the Governor to request me no longer to compromise the neutrality of the French waters by establishing a blockade within their jurisdiction, but to anchor, when every hospitality and facility should be afforded me, or to take my position without the distance of a marine league from shore. At the same time, that, while under anchor weigh it was contrary to the police regulations of the port to communicate with the shore. " I consequently decided upon anchoring, which I had no sooner done than the French commander paid me a visit, offered me every civility and attention, saying that he did not doubt that all international law would be respected by me ; and in the course of conversation, quoting from Wheaton, reminded me that one belligerent could not depart until twenty-four hours after the other. I instantly got tinder weigh, with him on board, fearing that the Sumter should do so before me, as her steam was up. "I have now accepted the alternative, and established myself at the mouth of the harbour, without the marine league, with much anxiety lest during the darkness of the night, under cover of the high land, the Sumter should be able to get off without my being aware of it. " The majority of the town is in favour of the Sumter ; and with the utmost vigilance, which all on board exert, she may yet escape some night for want of signals from the shore to give us notice of her departure. " I am also in want of coal, and shall send over to St. Thomas to-morrow for a supply, as well as provisions, stores, &c., for when I leb I did not bargain for this blockade. 278 THE SUMTER AND IROQUOIS. XI. " The Sumter seems in good condition. The Consul informs me she has 120 men. She does not certainly appear to be in the dis- organized state in which late accounts have represented her. " She has latterly captured but two American vessels one the brig Joseph Parke, of Boston, on the 25th of September; the other the schooner Daniel Trowbridge, of New Haven, on the 27th of October. She has landed here fourteen prisoners on their parole. Three of the Joseph Parke's men (all foreigners) joined the Sumter. " I regret to give the Government so long and unsatisfactory a letter, but must avail myself of the opportunity for St. Thomas, which offers to-morrow. "I have, &c. (Signed) " JAMES S. PALMER, Commander. " To Hon. Gideon Welles, "Secretary of the Navy, Washington, D. C." "P.S. November 18. I feel more and more convinced that the Sumter will yet escape me, in spite of all our vigilance and zeal, even admitting that I can outsteam her, which is a question. " To blockade such a bay as this, which is almost an open roadstead, fifteen miles in width, the surrounding land very high and the water very bold, obliged, as we are by the neutrality laws, to blockade at three miles' distance, it would require at least two more fast steamers, and a vessel of war of any description in port to notify us by signal of her departure, to give any reasonable hope of preventing her escape. " Even now, moonlight though it be, she may yet creep out under shadow of the land, and no one be able to perceive her, she being always able to observe my position, open to .seawards. Though 1 have made arrangements to be informed by signal of her departure from shore, I fear I cannot depend upon the parties, so fearful are they of the authorities and of popular indignation. " I have done all I can, and if she escapes me, we must submit to the distress and mortification. " I believe we have no vessel on this station except the Macedonia, and there is no knowing when she may get up this way to learn our .situation. " I wish the Sumter were anywhere else except in this port, or under French protection. The authorities here, under plea of neutrality, are throwing every obstacle in my way, in the way of communicating with the shore. They are so full of punctilio, and withal so polished, that it is provoking to have anything to do with them."
Here, have a book:
https://archive.org/details/historicalaccoun00bernrich