[4] In 1859, James L. Day, agent of the New Orleans & Mobile Mail Line and a repeat customer of Sneden's, requested that the shipbuilder construct an iron-hulled steamer for his company.

[9][10] Seeking to further capitalize on its investment in ironworking equipment, Samuel Sneden & Co. submitted a bid in 1860 for the construction of a quarter-mile long, large-diameter iron pipeline across the Harlem River at Highbridge, Bronx, for the transport of water from the Croton Aqueduct to a newly built reservoir in Manhattan.

[12] Shortly thereafter, Sneden declared himself insolvent, and ceded his shipyard to his partner Rowland, who pledged to settle the failed company's outstanding business.

[15] His proposal was rejected as unfeasible, but he did manage to secure contracts for the manufacture of gun carriages,[11][15] and for fitting out of merchant ships purchased by the Navy for war use.

[17] In September, New York engineer John Ericsson presented the Navy with a proposal to build a radically new type of ironclad warship with a low freeboard and revolving gun turret.

On 4 October, he signed a contract with the Navy for construction of the new vessel, on the basis that Ericsson and his backers would assume all financial risk for the project and that the ship would be launched within 100 days.

[22] The Continental Iron Works also secured contracts during the war for construction of the turrets of another three monitors,[22] and additionally built the iron-hulled double-ended gunboat Muscoota.

[23] In the course of building the monitors, Continental's proprietor, Thomas Rowland, invented a number of new machine tools to expedite the work, one of which is said to have reduced the required workforce for a particular task by 75 men.

[24] By the end of the war, the Works covered an area of eight acres, and is said to have been so crammed with buildings and wood and iron stores that movement around the yard by its employees had become both difficult and hazardous.

[25] Shipbuilding contracts for the Continental Works also declined sharply, but the firm had done better during the war than some other Naval contractors,[26] and was evidently in a more sound financial position.

[29] A wide variety of other metal products was also produced by the Continental Works through the 1870s, such as giant cauldrons and vats,[31] machine tools, lifecars for lifesaving clubs,[27][32] and torpedo casings for the Navy.

[36] Shortly thereafter, however, New York engineer Phineas Burgess took the contract for the new Amphitrite-class monitor Monadnock, and Continental then accepted a subcontract from him to build the ship's hull.

[37][38] Construction of the vessel was subsequently suspended by government indecision[37]—causing great financial loss to Burgess in the process[39]—and was only finally completed in 1896 at the Mare Island Navy Yard.

[41][42] In 1876, the Continental Iron Works became a pioneer in welding technology when it successfully applied plate-welding techniques to the boiler furnaces of the monitor USS Monadnock.

[49] Other popular welded products produced by the company through to the beginning of World War I included gas-illuminated buoys, and steel digesters used to convert wood to pulp for paper-making.

After the war, the company continued to produce buoys and furnaces, but increasingly turned to the manufacture of gas mains and large-diameter welded water pipes for the bulk of its business.

[28] The latter product had a number of advantages over riveted pipes, including smooth interior surfaces, lessening water friction, and reduced leakage.