Ironclads and blockade: Britain vs Union

Dilandu

First Sergeant
Joined
Mar 16, 2015
Location
Moscow, Russian Federation
The idea of "Britain enter the war against Union/Union&Russia" seems to be one of the most interesting in realm of alternate history. Mainly because such alternative could have a serious historical basics, and was, actually, not very long from becoming a reality.

In this small article, I'd like to address the question "would the Royal Navy be bable to sucsessfully blockade the Union coastline in 1863-1865"?

The general british strategy always favoured close blockade. In the era before radio, this was, basically, the only way to prevent large number of raiders from exiting and entering the enemy ports - if the enemy coastline was relatively long. Such strategy was the backbone of all planning against France, such strategy was implemented against United States in 1812-1815 with sufficient sucsess. So, we could assume that the Royal Navy would at least consider the close blockade seriously.

The main Union strategy would be the "punchers & runners" type of strategy; i.e. small forces of heavy units, capable to sortie and engage the blockade squadrons and either drive them avay or at least divert their attention, and number of fast raiders, who would use such moments to exit or enter ports. Such strategy was born after the experience of latter parts of 1812-1815 war, where the tight blockade prevented the USN raiders from entering and exiting.

So the question is: which side could be more sucsessfull in 1860s, at the dawn of ironclad revolution that shattered all centuries-long tactical and shipbuilding experience?

Let's calculate the ironclads first:

Royal Navy ironclads, 1861-1865:

* Warrior (1861)
* Black Prince (1862)
* Defence (1861)
* Resistance (1862)
* Royal Oak (1863)
* Hector (1864)
* Achilles (1864)
* Prince Consort (1864)
* Researhc (1864, small)
* Enterprize (1864, small)
* Royal Sovereign (1864, coastal)
* Caledonia (1865)
* Scorpion (1865, coastal)
* Wyvern (1865, coastal)

Assuming that the British would boost the production, we could also consider possible to comission some additional ironclads in late 1865; "Ocean", "Lord Clyde", "Lord Warden", "Pallas", "Zealous" & "Bellerophon".

Union ironclads, 1862-1865:

* New Ironsides (1862)
* Galena (1862, small)
* Keokuk (1862, small)
* Roanok (1863)
* Onondaga (1864)
* (Italian-ordered ironclad No.1 from Webb) (1864) - let's call her "Lafayette"
* (Italian-ordered ironclad No.2 from Webb) (1864) - let's call her "Rochambeau"
* Dictator (1864)
* Agamenticus (1864)
* Monadnock (1864)
* Miantonomoh (1865)
* Tonawanda (1865)

Assuming that the Union would also boost production, and cancel river monitor program (Casco-class were useless anyway) they would probably be able to bring "Dunderberg", "Puritan", and Steven's Battery in comission in 1865. And, I don't count the coastal monitors here - only the ships with as least limited ability to operate in sea.

As we could see, the numbers of ironclads comissioned is, actually, comparable. Of course, the Royal Navy still have numerical superiority, but the ratio is close to 1.5-to-1 or 1.7-to-1 - not the general 5-to-1 advantage that Royal Navy enjoyed over the Union wooden ships. One of the reasons for such, is that the Union Navy - who tended to act in home waters - could build smaller, coastal ironclads, with ilimited seaworhtness, while the Royal Navy would be forced to use large, sea-capable ironclads. In other terms - the Union could have same fighting power for the less cost than Britain, because the Union ships don't need to cross ocean and stay in open sea for long time.

And that we must adress the ultimate advantage of the Union.

Their naval bases.

The situation is, that the Union ironclads have their supply and repair bases - and quite good bases - exactly nearby. They have all Union coastlines for that. They stand on their bases, and sortie into sea from them to engage the Royal Navy blockade forces in close proximity.

The Royal Navy situation is much worse, because, simply speaking, they don't have any bases - or even simple stations - on Union coastline. Their closest shipyards are in Halifax (300 nm from Boston, over 500 nm from New York) and on Bermudas (over 600 nm from Hampton-Roads). To get repair or to be supplied, they would be forced to sail for days - even just to get coal, which they would need constantly. The Confederacy ports aren't the solution either; the majority of them simply could not service any large naval force, and the closest - Wilmington - is still 300 nm away.

So the general situation is, that Union ironclads have the advantage of acting from their operational bases, and the RN ironclads are forced to operate from bases hundreds of miles away. And - with all respect to Halifax naval engineers - said bases aren't as well equipped and supplied as Union ports. I.e. the damaged Union ironclad could be reparied and put back in comission several times faster than damaged RN ironclad.

And the Union coastline is big. To provide any blockade that would no be completely meaningless, the Royal Navy would be forced to have independent squadrons for:

- Hampton Roads
- Delaware Bay
- Lower Bay
- Long Island & Rhode Island
- Maine Gulf & Cape Cod

I.e at least five points.

For example:

Let's take Norfolk and Hampton-Roads. Due to the value of Norfolk and Cheasapeake Bay, and the existence of numerous shipyards nearby, we could assume that this region would be heavily protected with Union mobile forces - and the existence of Cheaspeake-Delaware channel also.

So, if blockade squadrons were recalled, it would means that both "New Ironsides" and "Roanoke" (and, probably, "Keokuk") would stand here, aided with "Minesotta" and "Wabash" and at least twenty or more both screw and sidewheel gunboats.

To block such force, the Royal Navy, of course, would be forced to send no less than two ironclads just to have similar numbers. To have some superiority, they would need to send three. The large advantage that Royal Navy have in wooden units basically have no value; if the RN ironclads would be beaten, the screw frigates and ships-of-the-line would have to run or be destroyed by Union ironclads.

But would three ironclads suffice? Let's assume that Union forces sortie, clash with RN ironclads, make serious damage to one, and escape back in base. Both Union ironclads would, probably, be damaged also, but they have their shipyards nearby. So they could be repaired quickly. The RN danaged ironclad would be forced to sail to Bermudas and have the repair here. It would probably took three-four times more time ( :smile: ) to repair the British ironclad. Which means, that the Union ships would have even odds until the repaired ironclad return. And if two RN ironclads would be damaged (not only in combat, but by accidents), the Union forces would have numerical advantage. And we not even started to addres the matter of coaling of RN ships near enemy coastlines, without so much as safe station.

So, to block the "New Ironsides" and "Roanoke", the Royal Navy would be forced to send at least two times more ironclad. Say, four. Problem is, that this number is exactly two-thirds of all avaliable RN ironclads in 1863. And all those ships are used to blockade one single point.

Now, let's assume that in 1864 the Union would have two "italians" in New York and "Onondaga" also here... Which would means that the Royal Navy would be forced to send at least six ironclads to watch over New York and still have at least four to block Hampton-Roads.

And Royal Navy simply haven't got as many ironclads. They only have 11 ironclads in 1864, of which two are small ironclad sloops and one - coastal unit, unfit for long ocean campaing. So, they basically have only nine ironclads.

In late 1864, the Royal Navy would also be forced to deal with "Dictator" in New York, "Agameticus" and "Monadnock" in Boston (not counting coastal units), which would require sixteen ironclads to blockade them. They obviously haven't got that kind of sea power. Even in early 1865, the number of comissioned Royal Navy ironclads was barely 14 (counting the coastal and small units). If such ships would be separated - assuming that they left no one on any other theater (the French Navy would surely be quite delighted by such action - which left the English Channel and Mediterranian at the mercy of French ironclads, which they have the same number as Britain) and no one is repaired or refitted in Britain - this would mean no more than limited forces at each blockade point.

This, basically, made close blockade for Royal Navy... impractical.

The most probable outcome is, that Royal Navy would be forced to abandon blockade, instead concentrating on sea denial strategy - i.e. by positioning squadrons of sea-capable ironclads in Canada and in Confederacy ports, to block any Union naval advance against such regions. They lose initative, of course - but it's best than lose ironclads in unspecified numbers. The disadvantage, of course, would be that Union would be able to concentrate the forces - and also that the Union raiders would be able to exit and enter Union ports unopposed. But it seems to be more viable strategy, than risking destruction of Royal Navy battleline piece by piece in prolonged war of attrition!
 
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