This may have been true at the very beginning of the civil war. By the end of the war, I don’t think any foreign navy could have dominated the USA fleet in the way that you’re assuming Britain would have, though. Even assuming that the British had the inclination to committ full-force to the US civil war (which chances are exactly zero, considering their much more demanding interests in India, Africa, parts of Asia, and about 50 miles away in Europe) they would not have simply trounced the US navy. The very first and weakest of the US ironclads was at WORST an even-match for typical British warships, and according to most people was more than a match for the best of them. Even without a significant naval threat to the American blockade, and with American interest in a powerful navy relatively low on the wartime priority scale, the American fleet was no pushover. Throw in a strong British antagonist and subsequent higher priority the Americans would have placed on building a modern fleet, and I have no doubt that the British would have suffered terribly had they tried to intervene and break the American blockade.
I always thought Britain maintained naval superiority pretty much up to the end of WWI…and maybe even a touch beyond that as well.
I guess I didn’t realize the Union/American navy was more than a defensive or blocking force until pretty much in the run up to WWII…or perhaps post-WWII when our navy came into it’s own.
-XT
The American ironclads sacrificed a lot for their superior firepower. There’s no way in hell America could have maintained a worldwide empire with them, for example, because they didn’t have the capacity to carry a bunch of soldiers for long distances out on the open ocean for extended periods of time. The British navy was still the “best” navy in the world all the way through world war 1, but during the civil war the Americans were the best at making seriously freaking powerful short range warships. They developed specialized warships for a specific purpose - to maintain the blockade. That’s it. When a navy can focus so narrowly on a single purpose, you can’t expect a rival navy built to maintain a worldwide empire (and serve all the various roles that entails) to compete with it on its own terms.
Well…I didn’t know that. Excellent! Learned a lot from this thread. The Civil War period isn’t one I’ve really been that interested in before and so I don’t actually know all that much about it.
Thanks for the education guys! So…no way the Brits would have formally joined the war on the Confederates side, and if they had they may have gotten a bloody nose…and the South STILL probably would have lost. Is that a good summation?
-XT
That’s my prediction (is that the right word?).
It’s kind of crazy to think that the civil war could have been much MORE brutal and nasty than it already was, isn’t it? The Confederacy could have dragged the war on much longer with foreign intervention, even though they probably still would have lost in the end. That’s a pretty sobering and disturbing thought.
Maybe if a foreign power had intervened on the Confederacy’s behalf and allowed the Confederacy to fight longer, even more hatred would have built up between the north and the south by the end of the war. There might be a lot more people today who still harbor resentment, in the way that only crazy fringe South Carolina “we never officially surrendered” groups do now. The Reconstruction era could have been much more brutal than it was, and the southern states might be much worse off economically even today. They’re still suffering the effects of their weak agricultural economy (which was mostly destroyed by the union) today, shown by welfare dependence, literacy rates and education levels, lower median income, health insurance availability, infant mortality rate, and all sorts of other things. I think all of that ties into how thoroughly the union destroyed the confederate economy and how punishing the union Reconstruction was (which was much less punishing than it could have been, due to Lincoln’s insistence).
Imagine how much worse things would be today if Union soldiers had felt more angry, frustrated, and hateful as they marched through the South during the end of the war after Atlanta, and if the Union politicians had even more built up resentment during Reconstruction and less time with Lincoln’s moderation to take the edge off the resentment.
Also, what would have happened between America and England politically? A USA with more internal strife and less goodwill toward the English would have been much harder to convince to enter WW1 on the “right” side. That could have led to even worse future consequences than the immediate ones after the civil war.
I think this would be a much more interesting Alt-History. In the Real World we know and love, the U. S. of A and England were Not Friends At All for decades following the Civil War. We were probably closer to Germany than England. This was the major era of American isolation, more or less, and saw the brief rise and quick fall of an Euro-style imperial possessions. (We realized we had not reason to have one and mostly walked away wondering why we ever wanted it in the first place.)
However, events in Germany itself (Kaiser wWilhelm was a moron) as well as old wounds healing led to England and America having a bit of a rapprochement before WWI.
In Harry Turtledoves series the Union actually comes into WWI on Germany’s side while the Confederacy is on the side of the Brits and France.
-XT
That seems unlikely. Prussia was considered a very minor power in 1862. It wasn’t until it won the Second Schleswig War in 1863, the Austro-Prussian War in 1866, and the Franco-Prussian War in 1870 that it was recognized as a major power.
The British Admiralty was starting to worry. Not specifically about the United States Navy but more generally about the possibility that its fleet was full of warships that were now obsolete. It doesn’t matter if you have five hundred wooden sailing ships if the state-of-the-art is a steam-powered ironclad. The new technology was far from perfect and the newest ships couldn’t handle traveling any distance from their home waters. But defensively in those home waters, they were very strong. You’d have ended up with a stalemate where the American ships were too vulnerable to the elements to come out and fight the British and the British ships were too vulnerable to being attacked to come in and fight the Americans. As a blockade it would work to the British advantage; American merchant ships couldn’t have sailed out past the protection of the coastal-bound warships.
The British had faced the same dilemma during the Napoleonic Wars; they kept their fleet on station off the coast of Europe and would have won if the French came out to meet them. But the French refused to come out to be defeated so the war dragged on for almost twenty years. As I wrote above, naval superiority doesn’t project well.
Ok. I got home, and now have cites to (sorta) back up my statements.
I am pulling my info from British Battleships, by Oscar Parkes, which goes into detail the design histories and particulars from every armored “battleship” built by Britain from Warrior (1862) to Vanguard (1946).
On page 6 (a one page Chapter [4] titled The 1858 "Naval Scare"):
This means the British themselves felt that they did not possess a navy larger than France, in direct reply to your question above.
This happens again (with France and Russia in the 1870’s) and again (with Germany in 1908) in the pre-WW1 years.
Each time spurs either a scramble to obtain hulls (like in 1908’s “We want eight, and we won’t wait!”), or a revolution in Naval power (like with Warrior in 1862, or Dreadnought in 1905).
On page 8:
These frigates directly influenced British designs of the period, which opted for higher speed (to dictate battle range).
I shouldn’t have used the word “alarmed”, I guess, but maybe “concern”. 
Effectiveness of the initial breechloaders is discussed on pages 13 and 14.
Tests were done vs. a standard 4 inch wrought iron plate with 7 inch oak backing (which was the hulls of the target hulks).
The 40lb Armstrong breechloader (tested in January of 1859) and the 100lb Armstrong breechloader (tested in September of that year) failed to penetrate the target from a distance of 50 yards! These were tested with a mix of iron and steel shot.
Meanwhile, the 68lb Whitworth rifled muzzleloaders (tested in October of 1858) was tested at ranges of 350 to 400 yards. With cast-iron shot, the hits cracked the plates, but did not penetrate. Wrought iron shot pierced both plate and oak backing. (The gun burst on the first wrought iron shot test. I don’t know if that was due to wear & tear on the gun, overcharging, or some other cause.)
Also, these series of tests in 1858 proved that a solid plate is more effective than layers of plate of equivelant thickness. (That is, a single 4 inch plate was better than 4 pieces of one inch plate.)
Wrought iron was found to be better than the steel of the day, which was too brittle… shattered almost like glass under force strong enough to penetrate. Iron was more flexible, and absorbed blows better without shards flying around.