The Great Western Company overcame the advantage of the Cunarders in the latter's high mail subsidy by increased enterprise and superior management; and prospered. In 1843 they launched the _Great Britain_, the largest and finest steamship up to that period built for overseas service.[AB] She was, moreover, distinguished as the first liner to be built of iron instead of wood, and to be propelled by the screw instead of the paddle-wheel. In the latter innovation, however, she was not the pioneer. Again the Americans were first in the application of the auxiliary screw to ocean navigation,[AC] as they had been first in despatching a steamer across the Atlantic. The initial transatlantic subsidy to the Cunard Company was followed up in 1840 and 1841 with contracts for steam mail-carriage to the West Indies and South American ports.[AD] The first (1840) went to the Royal Mail Steam Packet Company, for the West Indian service, the mail subsidy fixed at two hundred and forty thousand pounds a year;[AE] the second (1841), to the Pacific Steam Navigation Company. The latter enterprise was promoted by an American,[AF] after he had failed to obtain support in his own country[AG] for a project to establish an American steamship line to ports along the west coast of South America, a field in which American sailing ships had long been preëminent.[AH] Up to 1847 the British lines monopolized the transatlantic service. Then the situation became enlivened by the advent of competing American steamships subsidized by the United States Government, with high-paying mail contracts. The first of these was the New York, Havre, and Bremen line starting in 1847; the next, the celebrated Collins Line between New York and Liverpool, underway in 1850. The competing vessels were American-built, wooden side-wheelers; those of the Collins Line superior in equipment and in passenger accommodations, and faster sailers, than the British craft.[AI] To meet this competition the Cunard Company increased their fleet while the Admiralty increased the subsidy. Four new steamers were first added, in 1848, to run directly between Liverpool and New York, and the postal subsidy was raised to one hundred and forty-five thousand pounds a year for forty-four voyages--three thousand nine hundred and twenty-five pounds a voyage.[AJ] The competition began sharply with the regular running of the Collins liners, in 1850. Meanwhile during this year and the next additional contracts were given the Cunard Company for carrying the mails between Halifax, New York, and Bermuda, on the North American side, in small steamers, fitted with space for mounting an 18-pounder pivot-gun, subsidy ten thousand six hundred pounds a year; and for a monthly mail conveyance between Bermuda and St. Thomas, subsidy four thousand one hundred pounds a year.[AK] These services united the West Indies with the United States and Canada.[AK]