ed Part I
How Steamships Paddled out of the Shallows into the Ocean World Steamboats were a mechanical curiosity arousing little public interest two hundred years ago, when the first experimental vessels were built. But within the next half century they took over the waterways of America and Europe, and by 1838 regular transatlantic service had begun. By then , the idea of the steamer and the steam rai 1road had captured people 's imaginations, as they began to see the world transformed by this undreamt capability of power and movement which seemed to betoken an actual change in the natural order of things . It was in this aura of visionary change that the ocean-going steamship set out and, in the next half century, took over the sea routes of the world. Significant steps in the developing technology that made this possible were Brunel 's supership Great Britain of 1843-incorporati ng the innovation s of iron hull, compartmentation, double bottom, screw propeller-and the introduction of the compound engine in the 1860s, which cut fuel consumption in half, lengthening the short tether the steamer had had to work on. In the early 1900s, the turbine and the water-tube boileropened furtheradvances, leading to the ultimate passenger steamship, the United States of 1952, and the ultimate freighter, the SL-7 of 1972. 12
By Peter Stanford What survives of thi s period of sweeping advance in ocean navigation? Precious little; but the ships that have been preserved help us understand hi story . And what significance did the oceangoing steamer have in world history? Plenty; in fact the visionaries seem to have been right, and the ocean-going steamers that spread over the seas wrought change more far-reaching perhaps than their operators ever realized. The path of progress looks simple in retrospect. In 1712 Thomas Newcomen built the first of hi s "atmospheric" engines used to pump ground water from English coal mines. The role of steam in these enormous engines was simply to be condensed, forming a partial vacuum in an open-headed cylinder, which drew the piston down with great force. A counterweight ponderously raised the piston again, and the cycle was repeated- perhaps ten times a minute. In 1775, James Watt contributed the invaluable step of condensing the steam in a separate chamber, which sucked the piston down without going through the work of cooling off the cylinder. This immediately doubled the cycl ic rate from
about 10 to 20 strokes a minute, and cut fuel consumption 50%. This engine was becoming a practical proposition for more varied uses than fixed-place pumping. He also closed the top of the cylinder and created adouble-actingengine, with steam alternatively being fed in and condensed at both ends of the cylinder. And he developed gearing to transform up-and-down motion into rotary motion to drive wheels around rather than lift water in a pump. On the Delaware River at Philadelphia, John Fitch, a transplanted Connecticut Yankee, got a four-knot steamboat going in 1787. He ran this boat and successors on trials for the next few years and even got a few paying passengers before going out of business for lack of fund s. This remarkable man was crotchety to a degree, at war with establi shed religion, with half his friends and supporters, and, it would seem, with himself. His boats were regarded as interesting mechanical devices, part of the general flowering of mechanical invention that broke out as the Industrial Revolution gathered headway. But Fitch had a broader vision of his own work. He did not see the steamer merely facilitating river and harbor traffic, but changing the ocean world. He wrote: SEA HISTORY 64, WINTER 1992-93