USS Cairo (1861)

History of the USS Cairo (1861)

USS Cairo (1861) was a city-class armored gunboat built for the United States Department of War by the James B. Eads Company of Mound, Illinois during the American Civil War. She was the first ship in the City class, also known as the Cairo class. Cairo began serving in the Army and was commissioned as part of the Federal Army's Western Gunboat Fleet and served in the Army's Western Gunboat Fleet under the command of Flag Officer Andrew Helford. USS Cairo is one of seven armored gunboats named in honor of the city along the Great River. Cairo was handed over to the Navy on October 1, 1862.

Ironclads are impressive ships with thirteen guns of various sizes. Ironclads were a new naval technology for the navies of the 19th and early 20th centuries, bridging the gap between wood and iron construction and from sail to propeller/propeller (steam) propulsion.

They are proactive and creative in their designs, some succeed and some fail, but to fully understand the evolution of warships, the importance of these ships cannot be overlooked.

In 1822, Henry Packerhans pioneered the invention of the explosive bomb, hence the need for ironclad ships like Cairo. With this new technology, naval warfare has entered a new era of artillery, where explosive shells are fired in a horizontal trajectory, causing them to break through the wooden ship and explode inside, killing the crew and destroying the battery. By the time of the Civil War, the rifled gun was a relatively new development in naval artillery. This new weapon model is a tin boat with an exploding shell, making the wooden boat model that has been admired for hundreds of years obsolete.

Battleships like the Cairo became the main naval battleships of the Civil War. Many navies in the world have become second-rate navies.

Gunfire tests conducted by both sides early in the war indicated that two inches or less of armor was insufficient to withstand exploding naval fire. However, technology at the time only allowed for the production of 2-inch iron plates, so most iron clads had multiple layers, called plate lamination.

Two layers of 2" boards are usually the standard for iron armor, and some have a third layer. Plates are usually rolled or cast into rectangular blocks and rolled to the desired size, but on some ships the plates are actually hammered from forging.

This hammering, while time-consuming, makes up for the armor strength.

All forms of ironclad are new and untried, and some unusual combinations are created. Tried a track and panel system with an externally plated T-track configuration installed in an overlapping fashion, but this proved to be insufficient.

Wooden slats separated by edged iron plates or bars have been tried and failed. Some ironclad builders used a layer of rubber under the iron plate in the hope of deforming, but the rubber quickly rotted away. In another attempt at transfer, the armor was coated with lard or grease, which was ineffective in the hot sun, and the smell was a major problem for the crew. Their weakest point is the torso. Not only is the hull easily penetrated, but once breached, there is no way to isolate the damage, for example by means of a watertight compartment.

This makes them vulnerable to landmines.

It has been determined that the best armor configuration during the Civil War was the precursor to composite armor, which consisted of multiple layers mounted on a solid wood base. The big factories are in the north, and their iron armor will be more durable if the south has enough iron and forges to cover their ships with iron plates of six inches or more. City-class ironclads are designed with armor to protect the bow and front, as well as armor to wrap the boilers and engines. The wheelhouse or bridges were reinforced, but the armor was limited to other areas of the ship. Over time, more armor was added to the interior of the ship to protect the steam drums and engines.

Overall armor was inadequate in two respects, the deck and stern were exposed, and the lack of deck armor made her vulnerable to heavy fire.

Iron River engines, very similar to steamboats, are inexpensive to build, easy to maintain, and can run on firewood if necessary, losing some power if the main fuel, coal, is not available. Steam engines of that era were often described by the number of boilers, bore or diameter and stroke, or distance traveled by pistons, and the horsepower required to propel the ship.

Most ironclads are powered by propellers, but some use inner wheels like the Cairo. Their steam engine was powered by five fire tube boilers with a 22-inch cylinder with a 6-foot stroke that produced 140 psi (965 kPa) of pressure.

Wheels are clearly a worse propulsion option than screws, and in some ships like the Cairo, the wheels are moved inboard for protection. Despite not using screws, she was the fastest in the class.

Coal-fired steam engines created ongoing concerns about crew health and the efficiency of ventilation and draft engines. Fans circulate fresh air throughout the ship, and ventilation systems draw fresh air into the furnace. When this system works, the crew is not affected. To achieve this, an engine-driven fan and blower system is used to force fresh air into the boat. To aid air circulation, small sails are installed on the open deck portholes to capture fresh air and improve ventilation below the deck.

In battle, the portholes were covered with armor plates. Ironclads rely on their chimneys for engine power. When smoke and hot air are drawn from the chimney, negative pressure is created in the combustion chamber, drawing in the fresh air needed. During the battle, as the funnel was shot down, the engine's pull was reduced and the ship lost power.

The interior cabins filled with smoke, and the crew's combat capability was also reduced. From the early days of steam voyages, ironclads were designed to operate in calm waters.

This river use requires a shallow draft capable of carrying the heaviest loads, so a flat bottom design is best in shallow rivers.

Steering is still done by wheels and passed to the rudder via tiller ropes and pulleys, just like in the age of sailing. The protection of these ropes is very important when the damaged steering ability is lost and the vessel is grounded normally. Communication between the pilot and the cabin is still through bells and hollow tubes to give commands. This onboard internal communication system continued to be used in shipbuilding during World War II. Use the runner to send a message when the tube is broken.

Signaling between ships was carried out by flags, lanterns and missiles. Army semaphore personnel are also sometimes deployed on ships to communicate between the ship and the Army through semaphore codes.

Airborne firearms are usually rated in inches or pounds (weight of bullet or bullet) in the chamber. Rifled guns have significant advantages over smoothbore guns in terms of range, accuracy and penetration. Cairo has 13 guns of different sizes, 6 x 32 lbs, 3 x 8 inches, 3 x 42 lbs and 1 x 30 lbs.

Each gun has a separate crew to operate the gun. The 32-pounder has 10 men and a boy, the Powder Monkey, 8-inch and 42-pounders require 14 men and a boy, and the 30-pounder requires 12 men and a boy. The gunners on the Cairo mirrored the routine of gunners on wooden ships. The main types of ammunition used were explosive grenades and stationary shots, but grape rounds were still available.

Bombs with variable time fuzes are effective against wooden ships and fortifications. Wooden boats will be set on fire, and the explosion of cannonballs will throw deadly shrapnel in all directions, intent on killing the crew.

Grapeshot is also an anti-personnel shot, a grenade that turns a cannon into a giant shotgun.

On May 11, 1862, in a skirmish with Confederate gunboats at Plum Point Bend, Cairo and her sister ships forced the Southerners to evacuate the fort by June 4. Two days later, on June 6, near Memphis, Tennessee, in Cairo, seven Confederate ships engaged eight Confederate gunboats in a fierce battle. Five gunboats in the south were sunk or stranded, two were damaged, boarded and hijacked, and one gunboat escaped. It was a major victory that helped remove southern control of the river.

The Army of the North wanted river barges to control the Mississippi and Ohio Rivers, which would cut the South in half. On December 12, 1862, he was assigned to clear the river of mines in preparation for the attack on Haines Bluff, Mississippi, three days later.

During this operation, Cairo hit a mine detonated by southern soldiers hiding on the riverbank. The Cairo sank in 12 minutes, and all were able to disembark without casualties, becoming the first armored battleship to be sunk by lightning.

Cairo was forgotten at the bottom of the river until it was discovered in 1956 by Edwin Bearss, Warren Grabau and Don Jacks. They used maps and divers to locate shipwrecks covered in years of river silt. Years passed, and she grew up in late 1964, with evidence that Cairo was indeed a wreck. It was added to the National Register of Historic Places on September 3, 1971. In 1972, Congress passed legislation authorizing the National Park Service to take ownership of Cairo and restore the gunboat display.

In June 1977, the ship was transported to the park and partially rebuilt on concrete foundations near Vicksburg National Cemetery. In October 1980, a museum was built and a shelter was built to cover the ship. The original shelter has been replaced with a fabric covering to provide better coverage.

The ship and artifacts were recovered from cannons in Cairo, and the crew's personal effects are on display at Vicksburg National Military Park in Vicksburg, Mississippi.

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