Ericsson collaborated on the design of the railroad steam locomotive Novelty, which competed in the Rainhill Trials on the Liverpool and Manchester Railway, which were won by inventor George Stephenson's (1781–1848), Rocket.

A new partnership with Cornelius H. DeLamater (1821–1889), of the DeLamater Iron Works in New York City resulted in the first armoured ironclad warship equipped with a rotating gun turret, USS Monitor, which dramatically saved the U.S. (Union Navy) naval blockading squadron from destruction by an ironclad Confederate States naval vessel, CSS Virginia, at the famous Battle of Hampton Roads harbor at the southern mouth of the Chesapeake Bay (at the confluence of the James and Elizabeth Rivers) in March 1862, during the American Civil War (1861-1865).

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.

However, his heat engine was not a success, as his prototype was designed to burn birchwood and would not work well with coal (the main fuel used in England).

[6] Notwithstanding the disappointment, he invented several other mechanisms instead based on steam, improving the heating process by incorporating bellows to increase oxygen supply to the fire bed.

It was widely praised but suffered recurring boiler problems, and the competition was won by English engineers George and Robert Stephenson with Rocket.

An engine Braithwaite and Ericsson constructed for Sir John Ross's 1829 Arctic expedition failed and was dumped on the shores of Prince Regent Inlet.

At this stage of Ericsson's career the most successful and enduring of his inventions was the surface condenser, which allowed a steamer to recover fresh water for its boilers while at sea.

The commercial failure and development costs of some of the machines devised and built by Ericsson during this period put him into debtors' prison for an interval.

[12] He then improved ship design with two screw-propellers rotating in opposite directions (as opposed to earlier tests with this technology, which used a single screw).

However, the British Admiralty of the Royal Navy disapproved of the invention in the late 1830s, which led to the fortunate contact with the prominent American naval captain (and later commodore) Robert Stockton (1795-1866), who had Ericsson design a propeller-driven steamer for him and invited him to bring his invention across the Atlantic Ocean to the United States of America, as it would supposedly be more welcomed in that more free-thinking place.

The gun had also been designed by Ericsson and used hoop construction to pre-tension the breech, adding to its strength and allowing safe use of a larger charge.

When Ericsson arrived from England and settled in New York City, he was persuaded by Samuel Risley of Greenwich Village to give his work to the Phoenix Foundry.

Ericsson's engine was not initially successful due to the differences in combustion temperatures between burning Swedish wood and firing of British coal.

[23] A group of New York merchants and financiers headed by John B Kitching, Edward Dunham, President of the Corn Exchange Bank, and G.B.

Lamar, president of the Bank of the Republic, backed the project and in April, 1852, the keel of the ship was laid at the yard of Perine, Patterson, and Stack in Williamsburgh.

Hull and machinery were built in the greatest possible secrecy, both Ericsson and his financial backers being convinced that their ship would revolutionize ocean transport by its economy and safety, and that competitors would if possible copy the design of at least the engine.

Shortly after the American Civil War broke out in 1861, the Confederacy began constructing an ironclad ram upon the burnt hull hulk of the USS Merrimack which had been partially burned and then scuttled / sunk by evacuating Federal troops before it was captured by militia forces loyal to the local Commonwealth of Virginia.

Ericsson later presented drawings of USS Monitor, a novel design of armored ship which included a rotating turret housing a pair of large cannons.

Despite controversy over the unique design, based on Swedish lumber rafts,[26] the keel was eventually laid down in a New York shipyard and the experimental ironclad was launched on March 6, 1862.

The new Monitor appeared the next day, initiating the first battle between ironclad warships on March 9, 1862, at the Hampton Roads harbor of southeastern Virginia.

The rotating gun turret in particular is considered one of the greatest technological advances in naval history, still found on modern warships today.

[28] His wish to be buried in his native land sparked a series of articles in the New York Times alleging that, by selecting the third-rate USS Essex (1874) to transport his remains, the US Navy was not paying proper respect to Ericsson.