| FIG. 111.— | “GREAT EASTERN,” SCREW AND PADDLE WHEELS, 1858. LENGTH,692 FEET, SPEED 12 KNOTS. | |
| “OCEANIC,” TWIN SCREW, 1899. LENGTH, 704 FEET, SPEED, 20KNOTS. |
In 1854 the “Great Eastern” was begun and was finished in 1858. This was the largest steam vessel ever built up to this time, and has continued to hold the record for size up to the year 1899, when her dimensions were exceeded by the “Oceanic,” which ships are put in comparison in [Fig. 111]. The length of the “Great Eastern” was 692 feet, beam 83 feet, depth 571⁄2 feet, draft 251⁄2 feet, displacement 27,000 tons, and speed 12 knots. She was designed by the English engineer Brunel, and was intended for the Australian trade. She had both a screw propeller and paddle wheels at the side, with four engines coupled to each. The paddle wheel engines had steam cylinders 74 inches in diameter, with 14 foot stroke, and those of the screw engines were 84 inches in diameter and 4 foot stroke. Collectively they were of 10,000 horse power. The paddle wheels were 56 feet in diameter, and the screw propeller 24 feet. On her first voyage to New York, across the Atlantic, in 1860, she carried from 15 to 24 pounds of steam and consumed 2,877 tons of coal. Her cost was $3,831,520. This mammoth vessel was too large and unwieldy for the uses for which she was designed, and proved a bad investment. She served, however, a most useful purpose, by virtue of her great bulk, steadiness, and carrying capacity, for relaying the Atlantic cable in 1866, and others in 1873-1874.
In 1874 the “Castalia” was built. This was a steamer with two parallel hulls, decked across, and designed for greater steadiness in crossing the English Channel. The “Bessemer” steamer, designed for the same purpose, and built about the same time, had four paddle wheels, and the entire cabin was hung on pivots, so that it could not partake of the sea motion.
In later years great improvements have been made in reducing the weight of the engines, in forced blast, steam steering gear, anchor hoisting devices, water-tight bulkheads, surface condensers, electric lights, and signalling devices. By the year 1880 the standard form of marine engine for large powers had become the compound double cylinder type, expanding steam from an initial pressure as high as 90 pounds. In 1890 triple expansion engines had become common, employing three cylinders, and using steam with an initial pressure as high as 180 pounds. In 1890 McDougal’s whale-back steamers were introduced. See United States patents No. 429,467 and 429,468, June 3, 1890, and No. 500,411, June 27, 1893.
FIG. 112.—STEAMBOAT “PRISCILLA.”