The establishment of the Continental Works coincided with the outbreak of the American Civil War in April 1861, and later that year, Rowland became associated with New York engineer John Ericsson, who had just secured a contract with the United States Navy for the construction of a radically new type of ironclad warship with low freeboard and a revolving gun turret. Ericsson subcontracted Rowland for construction of the hull, and the new warship, known as , was launched at the Continental Works in just 101 days. When "Monitor" successfully neutralized the threat from the Confederate ironclad CSS "Virginia" at the Battle of Hampton Roads in 1862, a "monitor craze" took hold in Washington, with contracts for many more such warships being issued to firms around the nation. The Continental Iron Works would ultimately build seven monitors for the Navy during the war—more than any other company in the country. The Works also built the turrets for an additional three monitors as well as building an iron-hulled gunboat and doing other wartime work for the government. At one point in 1864, Rowland attempted to sell the Continental Works and go into early retirement, but this did not eventuate, and instead he would remain the company's president for most of his life.