ohn Ericsson was born at Långbanshyttan in Värmland, Sweden, but primarily came to be active in the United States.native of Sweden, John Ericsson (July 31, 1803 – March 8, 1889) was an engineering genius. He was born at Långbanshyttan in Värmland, Sweden, but primarily came to be active in the United States. He involved himself in the development or improvement of power transmission. He invented the ship propeller and later designed and built the Monitor for the US Navy in the War Between the States.

Early career
John's father Olof Ericsson who worked as the supervisor for a mine in Värmland had lost money in speculations and had to move his family from Värmland to Forsvik in 1810. There he worked as a 'director of blastings' during the excavation of the Swedish Göta Canal. The extraordinary skills of the two brothers were discovered by Baltzar von Platen, the architect of the Göta Canal. The two brothers were dubbed cadets of mechanics of the Swedish Royal Navy and engaged as trainees at the canal enterprise. At the age of fourteen, John was already working independently as a surveyor. His assistant had to carry a footstool for him to reach the instruments during surveying work.

At the age of seventeen he joined the Swedish army in Jämtland, serving in the Jemtia Field Ranger Regiment, as a Second Lieutenant, but was soon promoted to Lieutenant. He was sent to northern Sweden to do surveying, and in his spare time he constructed a heat engine which used the fumes from the fire instead of steam as a propellant. His skill and interest in mechanics made him resign from the army and move to England in 1826. However, his heat engine was no success, as his prototype was designed to use birch wood as fuel and would not work well with coal, which was the main fuel used in England.

Notwithstanding the disappointment, he invented several other mechanisms instead based on steam, improving the heating process by adding fans to increase oxygen supply to the fire bed. In 1829 his steam engine "Novelty" joined the Rainhill Trials, a competition arranged by the Liverpool and Manchester Railway, although it was the fastest in the competition, it suffered recurring boiler problems and could not continue to compete (after Stephenson had the judges change the rules which did not give Ericson enough time to properly reconfigure the engine) - the competition being won by the English engineer George and his son Robert Stephenson with Rocket. The many machines devised and built by Ericsson during this period put him in a harsh economic situation and at this time he also married 19-year-old Amelia Byam, a marriage that was nothing but a huge disaster.

Propeller design
Engraving of EricssonHe then improved the ship design with two screw-propellers moving in different directions (as opposed to earlier tests with this technology, which used a single screw). However, the Admiralty disapproved of the invention, which led to the fortunate contact with the encouraging American captain Robert Stockton who had Ericsson design a propeller steamer for him and told him to bring his invention to the United States of America, as it would supposedly be more welcomed in that milieu. As a result, Ericsson moved to New York in 1839. Stockton's plan was for Ericsson to oversee the development of a new class of frigate with Stockton using his considerable political connections to grease the wheels. Finally, after the election of President Tyler, funds were allocated for a new design. Unfortunately they only received funding for a 700-ton sloop instead of a frigate. The sloop eventually became the USS Princeton, named after Stockton's hometown.

The ship took about 3 years to complete and was perhaps the most advanced warship of its time. In addition to twin screw propellers, it was originally designed to mount a 12-inch muzzle loading gun on a revolving pedestal. The gun had also been designed by Ericsson and was the first naval gun to use the hoop construction method that pre-tensioned the breech, adding to its strength and safely allowing the use of a much larger charge. Other innovations on the ship design included a collapsible funnel and an improved recoil system.

Unfortunately, the relations between Ericsson and Stockton had grown tense over time and, nearing the completion of the ship, Stockton began working to force Ericsson out of the project. Stockton carefully avoided letting outsiders know that Ericsson was the primary inventor. Stockton attempted to claim as much credit for himself as possible, even designing a second 12-inch gun to be mounted on the Princeton. Unfortunately, not understanding the design of the first gun (originally name "The Orator", renamed by Stockton to "The Oregon"), the second gun was fatally flawed.

When the ship was initially launched it was a tremendous success. On October 20 1843 Princeton won a speed competition against the paddle-steamer SS Great Western, which had until then been regarded as the fastest steamer afloat. Unfortunately, during a demonstration firing of Stockton's gun the breech broke, killing the US Secretary of State and the Secretary of the Navy, as well as six others. Stockton attempted to deflect blame onto Ericsson with moderate success despite the fact that Ericsson's gun was sound and it was Stockton's gun that had failed. Stockton also refused to pay Ericsson and, using his political connections, Stockton managed to block the Navy from paying him. These actions led to Ericsson's deep hatred of the US Navy.

Ericsson then proceeded to invent the "hot air engine" in 1852 which used hot air instead of steam as a propellant, probably inspired by his earlier attempts of fume heat engines in Sweden. This engine was no success. In spite of this, Ericsson was awarded the Rumford Prize in 1862 for his invention. Already on September 26, 1854 Ericsson presented Napoleon III of France with drawings of iron-clad armored battle ships with a dome-shaped gun tower, and even though the French emperor praised this invention, he did nothing to bring it to practical application.

USS Monitor
John Ericssons grave chapel in FilipstadShortly after the American Civil War broke out in 1861, the Confederacy quickly began developing an ironclad based on the hull of the USS Merrimack which had been burned by Federal troops before the naval base at Norfolk - Gosport Navy Yard - had been captured by the recently seceded Commonwealth of Virginia. The United States Congress addressed this issue in August 1861 and recommend that armored ships be built for the Union Navy. Ericsson still had a dislike of the U.S. Navy but he was convinced by Cornelius Scranton Bushnell to work on an ironclad for them. Ericsson presented drawings of the USS Monitor a totally unique and novel design of armoured ship, which after much controversy was eventually built and finished on March 6, 1862. The ship went from plans to launch in approximately 100 days, an amazing achievement.

On March 8, the Southern ironclad CSS Virginia was wreaking havoc on the Union Blockading Squadron in Virginia. Then, with the appearance of the Monitor, a battle on March 9, 1862 at Hampton Roads, Virginia, ended in a stalemate between the two iron warships, and saved the Northern fleet from defeat. After this, numerous monitors were built, and are believed to have considerably influenced the victory of the Northern states. Although primitive by modern standards, many basic design elements of the Monitor were copied in future warships by other designers.

Later, Ericsson worked with torpedo inventions, in particular the Destroyer, a torpedo boat, and in the book Contributions to the Centennial Exhibition (1877, reprinted 1976) he presents the so-called "sun engines", using solar power as propellant for a "hot air engine". Once again bitter and plagued by economic difficulties, his invention of the solar engine would not have practical applications for another 100 years.

Although none of his inventions created any large industries, he is regarded as one of the most influential mechanical engineers ever. After his death in 1889 his remains were brought from the United States to Stockholm by USS Baltimore and to the final resting place at Filipstad, in his Värmland.