Ironclad Monitors 1863-1865

[Josh The Lighthouse Guy]

Building ironclads will-he-nil-he here & there consuming vast quantities of vital materials without even a ghost of a strategic or tactical doctrine was a formula for inevitable disaster. It was Clausewitz's worst nightmare.

Also, almost none of the Confederate ironclads seem to have solved the engine problems that were present from the start with CSS Virginia. Which is especially impressive since few, if any, Confederate ironclads shared a design and many were converted hulls. Many of the results were glorified floating batteries, too slow and cumbersome for active maneuver. CSS Manassas and CSS Atlanta were lost by accidentally running around during battles.

Mobile Bay also demonstrated the technology already existed to defeat ironclads, at least of the quality the Confederates could produce. 15" Dahlgrens or comparable heavy ordinance at close range wouldn't immediately penetrative ironclad armor but every shot did noticeable damage, and that was from only five such guns. The Union simply didn't have such weaponry widely available yet.

 

[Old Soldier]

This thread illustrates the same problems that the land war had - no one had really taken into account the changes in technology and had sufficient trained men to man them all. The Union had most of the 'big ship' shipyards and were making large seaworthy frigates. The Confederacy's few shipyards were still making seaworthy merchant vessels and used them for blockade running - but they still had to buy from abroad. The other shipyards were for river traffic - very important considering the lack of a railroad network like the North - relatively small vessels and more easily converted to counter the monitors.

The term 'ironclad' in Europe was associated with a seagoing vessel, usually made with a wooden hull, and clad in iron plate, but not unlike earlier wooden warships. Indeed, the Royal Navy had HMS Warrior, the first iron-hulled, armored warship in service in 1861 Yes, it was steam powered with screws, but it looked like any other full-rigged warship of the time. It was basically a broadside warship 26 x 64pdr SBML on the gundeck with 10 x 110pdr RBL top deck mounted - no reliance on barbettes and turrets.

The nearest to the monitor-type was the French (and British) floating battery used to hit shore fortifications and used in the Baltic and Crimea. These were basically ironclad broadside vessels, generally towed any distance, unlike the original bomb ketches, however, compare freeboard of the French Lave with the USS Mahopac:

Both did a similar job, but different designs for different environments.

 

[USS ALASKA]

Sirs, some additional citations on the USS Camanche...

Civil War Naval Papers | Naval War - At Sea & Along Inland Waterways

Journal Article "The Clangor of That Blacksmith's Fray": Technology, War, and Experience Aboard the USS Monitor David A. Mindell Technology and Culture Vol. 36, No. 2 (Apr., 1995), pp. 242-270 The Johns Hopkins University Press https://www.jstor.org/stable/3106372 Full article at above link...

civilwartalk.com

Cheers,
USS ALASKA

 

[Saphroneth]

The term 'ironclad' in Europe was associated with a seagoing vessel, usually made with a wooden hull, and clad in iron plate, but not unlike earlier wooden warships.

I wouldn't say that. The term "ironclad" wasn't yet invented when the Warrior, Gloire and the Crimean batteries were built - though it's certainly fair to say that the Brits in particular had the ability and desire to build ships with armour rather than building floating gun platforms. Even the "floating batteries" of the Crimean were quite shipshaped...

 

[Rhea Cole]

Also, almost none of the Confederate ironclads seem to have solved the engine problems that were present from the start with CSS Virginia. Which is especially impressive since few, if any, Confederate ironclads shared a design and many were converted hulls. Many of the results were glorified floating batteries, too slow and cumbersome for active maneuver. CSS Manassas and CSS Atlanta were lost by accidentally running around during battles.

Mobile Bay also demonstrated the technology already existed to defeat ironclads, at least of the quality the Confederates could produce. 15" Dahlgrens or comparable heavy ordinance at close range wouldn't immediately penetrative ironclad armor but every shot did noticeable damage, and that was from only five such guns. The Union simply didn't have such weaponry widely available yet.

Test target showing the effect of impacts by large caliber projectiles. What it does not show is the spall ejected from the opposite side of the plate.

Link to USS Lehigh:

Battleship Photo Index USS LEHIGH

As the photographs of the Monitor USS LeHigh's turret clearly show, its laminated armor plate successfully absorbed strikes from large caliber cannon fire.

The Monitor's turret reflected a lesson Richard the Lionhearted learned on his crusade. Château Gaillard, begun in 1196, has scalloped walls.

A curved surface both deflects & absorbs impacts by both100 pound stones or cannon shot.

Nothing quite so grand as a castle was needed to disable a stream driven vessel. These innocent lumps of coal are, in reality, infernal explosive devices.

CSA agents tossed these things into coal barges intended for Union riverboats & gunships.

 

[Saphroneth]

The Monitor's turret reflected a lesson Richard the Lionhearted learned on his crusade. Château Gaillard, begun in 1196, has scalloped walls.

The problem with the turret approach is that it means that you have a really huge amount of deck space taken up for a relatively small battery. The New Ironsides (as the closest comparable ship in manufacturing terms) has about eight times the battery of Monitor (16 heavy guns vs. 2) or four times the broadside on about four times the displacement; without the hammered wrought iron that made up the belt of the New Ironsides she'd have been heavier, but not by that much. The guns are then easier to work.

The Crimean-style floating batteries had the ability to provide more than half their guns on a broadside, and carried 14-16 heavy guns.


Ultimately a round turret means you're stuck with two guns per turret at most, and since the turrets are large and involve complex machinery they're easy to jam. It has defensive advantages, but it can compromise the ability of the ship to actually fight, so it's a tradeoff not an outright X-is-superior.

 

[USS ALASKA]

Ultimately a round turret means you're stuck with two guns per turret at most, and since the turrets are large and involve complex machinery they're easy to jam. It has defensive advantages, but it can compromise the ability of the ship to actually fight, so it's a tradeoff not an outright X-is-superior.

A tradeoff future warship designers gladly accepted as citadel designs fell by the wayside.

Cheers,
USS ALASKA

 

[Josh The Lighthouse Guy]

The Union had most of the 'big ship' shipyards and were making large seaworthy frigates.

Not frigates during the war, but yes seaworthy warships like the 90-day gunboats and armed sloops. They needed to have a chance of catching blockade runners which mean open water capability but limited need for guns since the runners were unarmed. A shot across the bow then a few into the engine if that wasn't enough. Broadsides were mostly when attacking fortifications, and often not effective in that role.

 

[Saphroneth]

A tradeoff future warship designers gladly accepted as citadel designs fell by the wayside.

Cheers,
USS ALASKA

This is true, but there's several factors involved. A key one is the increasing provenance of armour on the potential enemy targets.

A 68 pounder is able to do reasonable damage to most ACW armoured vessels, so you only really need a 68 pounder's capacity and you can fit a lot of them on a warship - the Aetna carried 16 of them and that was a small shallow-draft inshore vessel (shallower than Monitor, actually).

But as the 11" unbacked laminate of Monitor and the Passaics and the 2x2" backed of Virginia becomes the 5.5" rolled wrought backed of Lord Clyde, then the 6" rolled wrought backed of Bellerophon, the size of gun you need to penetrate becomes much greater. Warrior had carried 26 AP guns, while Bellerophon carried ten of her largest type of AP gun (giving her a broadside of five AP guns).

By that point, a twin turret design is not giving up much firepower. The fact that you are having to carry few large guns anyway means that the loss of firepower in a turret design is actually less. Turret ship Monarch and central battery ship Hercules, of about the same age to within a few months, both had a four gun broadside of their heaviest guns (and for Monarch those heaviest guns were somewhat heavier). This is to deal with a potential enemy threat with up to 10" rolled wrought iron backed, which is incredibly strong compared to the armour of Civil War monitors.


This is the result of a very rapid gun-armour race in the 1860s, but it's a race that the US didn't really keep up with.

 

[Rhea Cole]

I wouldn't say that. The term "ironclad" wasn't yet invented when the Warrior, Gloire and the Crimean batteries were built - though it's certainly fair to say that the Brits in particular had the ability and desire to build ships with armour rather than building floating gun platforms. Even the "floating batteries" of the Crimean were quite shipshaped...

Indeed, Nelson era first rate line of battle ships that hogged like bananas under the weight of iron plate armor were obviously transitional. It is useful to refer to the innovations that made every wooden hulled warship in the world obsolete.

In 1824 a French 2 decker Pacificateur was decommissioned & used as a target. French General Henri-Joseph Paixhan's new anti ship explosive round received its baptismal proof of concept. His innovative shell was fused to penetrate the target & explode after a delay.

The assembled officers were stunned when the warship was reduced to a flaming inferno, broke up & sank after only a few rounds.

It was an American Colonel named Bonford who worked with Paixhan to perfect a cannon adapted to fire the delayed fuzed shells.

In 1853 Russian & Turkish flotillas of (+/-) equal strength faced off at Sinop. Armed with Paixhan cannon & shells, the Russian ships lined up broadside to broadside in the time honored way. What followed was anything but traditional.

The delayed action Paixhan rounds penetrated the scaling of the Turkish warships then showered white hot shell fragments into the crowded gun decks. Secondary explosions & raging flames obliterated the ships & crews.

Every wooden warship in the world became obsolete at that moment.

Link to an excellent essay on the Battle of Sinop:

The Battle of Sinop and the End of Oak

In 1853 most of the world’s warships were still made from wood and powered by sail. The ships of the line that had dominated the great sea battles of the Napoleonic Wars continued to rule supreme in the navies of the world. In the decades after the fall of Napoleon there had been few major fleet...

www.philipkallan.com

 

[Santee1821]

To me the question is, did the resources expended for each of the navies produce ships which were capable combatants for the war.

The USN did this. The monitors, though limited to coastal operations, were capable of making adequate speed, had an effective armament, and were adequately armored against Confederate artillery.*

The CSN mostly did not do this. Most of its ironclads had woefully underpowered second-hand engines which in service quickly wore down to produce even less power. Even if they had been adequately armed and armored (which was less and less the case once 15-inch guns and large Parrott rifles came into US service), without engines powerful enough to move them they were of little use. In general, I think the guns would have been more effective mounted ashore.


*The most powerful guns USN monitors generally had to face were 10-Inch Columbiads and 7-Inch Brooke Rifles. It was those guns that left the dents on USS Lehigh and the others. The few more powerful guns (heavy Brooke smoothbores, the triple banded 7-Inch Brookes, the 12-Inch Columbiads being produced by Tredegar at the end of the war, and assorted imported heavy British rifles) were generally too little, too late. Had the Confederacy been able to produce or acquire more powerful artillery in numbers by 1863, I wonder if the armor of the monitors would have been sufficient.

 

[Old Soldier]

The main problem was the guns, rather than the mounting. Even at this stage, the breech-loading naval gun was suspect at the larger calibers/powder charge, mainly due to the technology and quality of metal used in their construction. Many navies, including the Royal Navy, stuck to the rifled muzzle-loader, with all its disadvantages, basically because of its weight of shot and range. This continued into the 1870s The Royal Navy was one of the last to change.

HMS Thunderer's 12" turrets (1872) with original manual muzzle-loading (later replaced by hydraulic loading apparatus). The gun is shown in it's 'run back' position for loading. it was then 'run up' for firing. YES, that is wood in the construction of the turret, but this was not structural, but as a buffer for solid-shot hits and as a 'spacer' for explosive shells. The 'hydraulic buffer' was to reduce recoil - one of the first.

The switch came in the 1880s, but many were not converted to breech-loaders until the 1890s (HMS Thunderer in 1888), if at all.

 

[Saphroneth]

Indeed, Nelson era first rate line of battle ships that hogged like bananas under the weight of iron plate armor were obviously transitional. It is useful to refer to the innovations that made every wooden hulled warship in the world obsolete.

No Nelson era first rate was armoured. The oldest RN ironclad to be armoured was laid down in 1849, converted to screw on the ways, launched in 1857 (and never commissioned owing to lack of need), and converted experimentally in 1862.

An 1850s screw liner is a very different beast from a "Nelson era" first rate, not least because it's about twice the size and has a powerful engine, along with having more guns with greater power. Comparing Victory to Duke of Wellington, the Victory had 102 guns averaging about 20 lbs per gun, the Duke of Wellington had 131 guns averaging about 32 lbs per gun. The difference is pretty much a factor of two in weight of shot alone.

In 1824 a French 2 decker Pacificateur was decommissioned & used as a target. French General Henri-Joseph Paixhan's new anti ship explosive round received its baptismal proof of concept. His innovative shell was fused to penetrate the target & explode after a delay.

The assembled officers were stunned when the warship was reduced to a flaming inferno, broke up & sank after only a few rounds.

This description sounds like you're describing percussive fuzes (i.e. impact fuzes) with a delay on them. To my understanding explosive shells at this time were time fuzed, and it was innovations in the 1850s which led to the early impact fuzed shells - notably, for example, the US Navy didn't have impact fuzed shells in the Civil War. (The British used the Pillar fuze for Armstrong rifles and the Moorsom fuze for smoothbore shells.)

The description I've read of the Pacificateur firing doesn't sound like the ship was set on fire, broken up and destroyed by only a few rounds. The damage that's done in first hand accounts of the trials suggests that holes were made up to three feet on a side - certainly significant - but the only mention of incendiary effect is that it would have burned the ship if assistance had not been at hand.

In 1853 Russian & Turkish flotillas of (+/-) equal strength faced off at Sinop. Armed with Paixhan cannon & shells, the Russian ships lined up broadside to broadside in the time honored way. What followed was anything but traditional.

Eh? It wasn't an equal flotilla. The Russians brought six liners, two frigates and three steamers to attack an anchored Turkish squadron (that wasn't ready for action) with nothing above a frigate; the Russians probably had at least twice as many guns.

ED: I've seen mention of the idea that the Turks actually set fire to their own ships, to prevent the Russians capturing them.

Every wooden warship in the world became obsolete at that moment.

Not really. Ships could endure long periods of bombardment in the Crimean War without being destroyed; witness HMS Agamemnon. She took 214 hits at Sevastopol and suffered 4 killed, 23 wounded.


What's going on here is that the explosive shell offers the opportunity for greater damage than a cannonball, assuming that the shell breaks through the sidewalls (which were very thick on a ship of the line, you can think of them as "woodclads" with up to three feet of wood as armour), but these are cannonballs with some gunpowder in them. They're not full of high explosive like lyddite, and even lyddite shells just produced a lot of high velocity splinters.
The description you give of white-hot fragments igniting fires throughout sounds more like Martin's Shot, a British weapon of the late 1850s and early 1860s which had a filling of molten iron.

 

[Saphroneth]

The USN did this. The monitors, though limited to coastal operations, were capable of making adequate speed, had an effective armament, and were adequately armored against Confederate artillery.*

The CSN mostly did not do this. Most of its ironclads had woefully underpowered second-hand engines which in service quickly wore down to produce even less power. Even if they had been adequately armed and armored (which was less and less the case once 15-inch guns and large Parrott rifles came into US service), without engines powerful enough to move them they were of little use. In general, I think the guns would have been more effective mounted ashore.

To be honest I think this assessment turns on two points.

1) What counts as adequate speed? The Monitors were often pretty slow - Passaic class ships tended to make about five knots.

2) What is the Confederate alternative? I know you say that the guns would have been more effective mounted ashore, but this I think misses part of the point of an ironclad - the fact that it is potentially operationally or strategically mobile changes the Union's threat assessment. There is no need to worry about Drewry's Bluff making a breakout down the James, but the Virginia II might do that; if the CSN is going to make a navy, they have to work with the engines they have. And if they're not going to make a navy, that basically means that for each ironclad they don't build they get maybe one extra shore battery - and I don't think that's a worthwhile tradeoff.

 

[Santee1821]

There is no need to worry about Drewry's Bluff making a breakout down the James, but the Virginia II might do that; if the CSN is going to make a navy, they have to work with the engines they have.

This line made me chuckle, and it raises a good point. Thank you for it.

The monitors were able to be moved from point to point and were able (generally) to get into and out of action. I know the use of CSN ironclads was different, but several were lacking those basic abilities.

Guns ashore don't require a hull constructed and iron drawn from limited stocks as armor. They suffer from the added weakness of being able to sink - whether from action or shipworms like CSS North Carolina.

Some CSN ironclads provided good service and forced the USN to deploy to counter them. I am not sure that the least well powered ironclads can be thought of as good investments, though.

 

[Saphroneth]

The monitors were able to be moved from point to point and were able (generally) to get into and out of action. I know the use of CSN ironclads was different, but several were lacking those basic abilities.

That's just because the USN controls the sea. It's not a flaw of the CSN ironclads - and the CSN certainly made efforts to get ships that could take control of the sea. The ships that became Kotetsu, Scorpion and Wivern would have been highly effective at neutralizing US sealane control.

The real issue I think is to point to a CSN ironclad which:

- was not effective at causing a USN response
- owing to flaws that could have been fixed by some other means
- and which the CSN could have known about or fixed in advance.

The North Carolina suffering from structural problems could have been fixed if the CSN had a source for seasoned timber. So did they?

And I'll note that the Casco class also suffered from construction problems - so it's not a binary thing where the CSN Did Bad and the USN Did Good...

 

[Santee1821]

That's just because the USN controls the sea. It's not a flaw of the CSN ironclads - and the CSN certainly made efforts to get ships that could take control of the sea. The ships that became Kotetsu, Scorpion and Wivern would have been highly effective at neutralizing US sealane control.

The real issue I think is to point to a CSN ironclad which:

- was not effective at causing a USN response
- owing to flaws that could have been fixed by some other means
- and which the CSN could have known about or fixed in advance.

The North Carolina suffering from structural problems could have been fixed if the CSN had a source for seasoned timber. So did they?

And I'll note that the Casco class also suffered from construction problems - so it's not a binary thing where the CSN Did Bad and the USN Did Good...

The Casco class was a debacle, and little good can be said about Galena and Keokuk as designs. I cringe at USS Roanoke's conversion which ruined a good ship and used enormous resources to produce a basically useless ship. The USN also built plenty of ships out of green wood - which meant that it was using its 1850s-built sloops and frigates as cruising warships well into the 1870s because so many of the war-built ships deteriorated so quickly. You are correct that it was not a binary thing. The USN probably wasted more resources on poorly built ships and bad designs that the CSN ever had. But the USN had the resources to make those mistakes and build - where needed - for short term needs only. And the USN did build plenty of ships which were useful for the war that they had to fight.

CSS North Carolina was a particularly poor ship and not a good example for the fleet as a whole. However, CSS Raleigh was better built, and was able to make a single sortie - where the blockading ships just moved away. Her subsequent loss was not due to her design or construction. Had she not been lost, would she have significantly impacted USN and US Army operations before, during, and after the fall of Fort Fisher? Maybe. Or would she have just provided a battle honor for a monitor as the USN moved up the Cape Fear?

What CSN ironclad ships were effective at forcing a USN response?

CSS Arkansas and CSS Albemarle caused quite a stir. Surely the ironclads of the James River and Charleston squadrons did better that the two ships at Wilmington. CSS Tennessee provided a good fight, but was anything else built at Mobile worth the effort? How meaningful was CSS Savannah's contribution to her namesake city's defense after CSS Atlanta was lost?

I know it is so easy to make judgments 160 years later from the comfort of my living room. I enjoy asking the questions and reading the answers.

Model of the converted USS Roanoke at the Hampton Roads Naval Museum

 

[Saphroneth]

So one thing that's important to remember is that the resources that go into the ironclads are often scarce in the sense that there is not a lot of them, but not scarce in the sense that there is a lot of demand for them. The time of shipbuilders for example is not really something you can transfer easily to any other task, and the number of people working on a given ship not really all that high - is an ironclad worth more than an infantry regiment? (Which is on par with what you'd get if you used the men for infantry work. Well, strictly you'd get the regiment for about a year.)

As for the iron, the same thing is at play. The Virginia, which was quite big, used about 640 tons of iron armour, and that could have been used to make rails instead... but not actually very much rail. Convert it at a typical figure of 45 kg per metre for rails and you get about 14,200 metres of iron rail... which amounts to about seven thousand yards of rail line, or circa four and a half miles.

Is an ironclad worth more than four and a half miles of rail?

In both cases, I think that it is.

 

[Saphroneth]

The basic structure of the naval war is that the Union is going to control the sea unless the Confederates can get outside support, where outside support means the ability to bring in British or French ships (by purchase or by intervention). Aside from that distant dream, the Confederates have two other purposes for their navy.

1) To conduct commerce raiding.

I would argue that this was successful. The "flight from the flag" generated significant pressure on the Union, and while they were overall able to cope this is a lot of outcome for what they used.

2) To contest control of Confederate littoral and riverways, denying the Union the ability to conduct specific types of naval mission, and harass their blockade stations.

This is really what the ironclads are for, and what they do. To have the maximum distracting effect they need to have a demonstrated ability to sally against a blockade station, but it's not really realistic for the Confederates to build a ship that could break the blockade - that would require them to build individual ships or a small squadron in a single port that was able to chase down Union blockaders while possessing a combination of protection and firepower that would let them fight the whole blockade squadron at once - regardless of the ironclads in it.
Harrassment is easier. The attacker gets to pick the conditions under which they attack, and the defender has to be constantly vigilant. If the defender is using sailing warships on the blockade (something the USN did in the early war at least) then there is the risk that the sail vessel will be unable to retire if threatened.

In harbour defence, the value of the Confederate ironclads specifically is that they are the manoeuvre element. A real vulnerability of coastal batteries in this period is against the attacker who manages to obtain a firing position from which they can fire at the fort without the fort being able to effectively return fire. A half-dozen gunboats totalling only a thousand tons of displacement and armed with one 7" rifle each could demolish a battery if they can find an angle that no defending guns shoot at.
Even a single ironclad eliminates this risk or massively reduces it. Since the ironclad is mobile, it can move to a position where it can engage the gunboats; since the ironclad is an ironclad, it can be fairly confident of winning a battle against unarmoured gunboats. It means that any attempt to set up in dead angles has to bring enough firepower and protection to fight the ironclad with a good chance of victory, and greatly amplifies the force commitment required to fight past the batteries.

Coastal batteries, minefields, and defensive ironclads benefit from combined arms - each additional element multiplies the total power of the defence.

 

[Saphroneth]

I cringe at USS Roanoke's conversion which ruined a good ship and used enormous resources to produce a basically useless ship.

So I would say the biggest problem with the Roanoke (apart from the loss of a good ship and the long time it took) is that it was armoured with hammered wrought iron. This is better than laminate (if inferior to rolled) and it took about a year to produce the plates. It was the single biggest bottleneck.

Consequently she's one of the only ships with the more efficient hammered wrought iron the Union could build in the entire war. New Ironsides had problems with the design, mostly relating to water flow around the hullform missing the rudder, but Roanoke had much more significant ones and basically the iron plates used for Roanoke could have been used to make a fixed New Ironsides.

That would be a pretty major increment of strength for the Union's efforts in port attack! The resultant vessel would have had the broadside of any four monitors and been more resistant to enemy fire, and without the rudder problems that meant New Ironsides had to be towed into position then this... Newer Ironsides... would have been quite effective.