Ironclads - History and Development

Learn about Ironclads - the fascinating historical development of capital warships between the age of sail ship-of-the-line and the all big gun dreadnought-type battleships.

Ironclads were the next step in capital ships after the wooden full rigged ships of the line. First to make claim to the name was the French La Gloire launched in 1859, and instantly all her contemporaries were rendered obsolete.

She was built as a full rigged ship of the line as before, only with a wooden hull covered in thick iron armor plate, auxiliary steam propulsion and a single gun deck with powerful rifled muzzle loaded guns.

First of the ironclads. French La Gloire, launched 1858.

As easy as it is to pin point the first ironclad, nobody has defined when the term fell out of favor. One thing is for certain though, by the launch of the first all-big-gun ship, HMS Dreadnought in 1906, all iron clads were themselves obsolete over night.

Civil War Ironclads.

When the American civil war broke out in 1861 the US Navy had no armored ships. Their most powerful ships were six steam powered, but unarmored frigates. Most of the US Navy stayed loyal to the the Union side, i.e. the North.

Quick to exploit the advantage, they started blockading the southern ports in an attempt to choke the export of cotton and tobacco, while at the same time starve the South of much needed imported arms and food. Lacking the industrial resources of the North, the desperation forced the Confederates to apply their ingenuity to try and shift the balance in their favor.

They started rebuilding steam ships into armored gunboats by cutting down the hulls leaving a minimal freeboard. Most famous of the Confederate Iron clads was the CSS Virginia.

She was originally the Union steam warship USS Merrimack that the Union troops had burned in an attempt to destroy her as they evacuated the Gosport Shipyard in Norfolk, near the Chesapeake bay, in 1861.

A new structure, a casemate was erected on top of the old hull made of oak and armored with iron plate. She was equipped with a ram and she was armed with all different kinds and calibers of guns.

Because these ships were designed for coastal operation and only for short missions, they carried no masts, sails or rigging, and only a few days worth of coal, ammunition, food, fresh water and supplies.

The panic was almost rampant in the blockading Union ships as they saw their bullets bouncing off of her casemate as she steamed straight for them. This was the prelude to the Battle of Hampton Roads where CSS Virginia rammed and sunk the USS Cumberland and forced the USS Congress to surrender in a matter of hours.

In the meantime the USS Monitor – the newly designed Union iron clad – had been rushed in to save the day for the blockading force. The following day the first battle between ironclads took place.

The battle that ensued was a four hour slug fest, after which both ships went back to their corners. The encounter was a draw tactically. It was a strategic victory for the North. The monitor had been proven an effective counter measure to the most dangerous challenge to the blockade so far.

The USS Monitor lent its name to a new ship type - the monitor. While the two sides fought on, the rest of the world watched and took note. As a result many navies started building monitors with heavy guns in one or two rotating turrets and no or limited rigging.

Oceangoing Ironclads

Experiences gained by the allies during the Crimean war lead to the first generation of iron clad armored warships. As mentioned before, the French La Gloire was the first such armored capital ship.

The Royal Navy responded the following year with the HMS Warrior. She was a much larger ship with thicker armor, heavier guns and a few knots faster.

The arms race was on and each newly launched capital ship was again obsolete in a decade or so. Nations like Austro-Hungary and Italy were soon getting their own armored battleship programs going.

The accelerated development of artillery and artillery shells lead to new ideas in gun placement and armor protection, such as central and box batteries, as well as revolving turrets - an idea borrowed from the monitors.

John Ericsson was a great mechanical engineer, but there is no mention of his abilities as a naval architect. The achille's heel of the monitor concept was its poor seaworthiness due to the heavy turret and low freeboard. Its vulnerability became embarrassingly clear when the USS Monitor sank under tow in heavy seas on December 31, 1862 in the Atlantic outside of Cape Hatteras, NC.

The era was full of confusion as to how future wars would be fought at sea. After the battle of Lissa 1866 between Italy and the Austro-Hungarian Empire, many thought the ram was to become the decisive weapon and just about all battleships and cruiser were equipped with one up until the self propelled torpedo became commonplace. The torpedo could do the same thing only from further away.

The HMS Captain was a fully rigged turret ship that capsized in 1870 due to instability problems. This was a wake-up call and several improvements were initiated:

• Starting with HMS Devastation 1871, the rig was finally abandoned for oceangoing capital ships. A lot smaller masts were kept for signaling purposes only.


• Armored decks and armor belts were introduced. On the monitors the upper deck was the armored deck. By building ships where the armored deck was internal, inside the hull and close to the waterline in combination with an armored belt around the waterline, the same level of protection was achieved.


• Revisit gun placement - turrets fell out of favor for a short time for the benefit of barbettes. After other issues were worked out the turret regain its proper role as the main gun emplacement.

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