Maritime Technology

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MARITIME TECHNOLOGY

From the earliest period of settlement, colonial Americans took advantage of cheap, available timber resources to build ships for fishing, commerce, and trade. Shipbuilding was particularly strong in New England, where, by the time of the Revolution, one new vessel was being launched every day. For most of the eighteenth century, ships were built according to traditional English construction practices, with few innovations. Shipping was dominated by smaller, slow-sailing carriers differentiated only by the number of masts, rigging plan, and size of hull. During the Revolution, construction of privateers provided shipbuilders with experience in designing faster, sleeker vessels. The post-Revolutionary economic recovery and explosive growth in trade created a need for fast, reliable means of shipping goods. In the 1790s a "mania for speed" seized shipbuilders and triggered a wave of experimentation with sail plans and hull design.

Answering the need for speed, many builders modeled their ships after the "Baltimore clipper," a late-eighteenth-century Chesapeake design that maximized the amount of sail and cut through the waters with sharp ends and a deep keel. The deep keel proved problematic, as many ports had only shallow harbors. The solution was the centerboard, or "dropkeel," which could be moved up and down in a watertight case to give the vessel a deep keel for fast sailing or a shallow draft for navigating in port. The centerboard had been invented in the 1770s, but problems with the watertight case kept it from general usage until it was perfected in 1814. The War of 1812 again provided shipbuilders with opportunities to design fast ships for privateers. After the war, high-risk ventures such as slaving, opium smuggling, and coffee and fruit trading kept shipbuilders competing to build faster ships with greater cargo capacities. This competition kept the fast-ship building tradition alive and proved crucial in establishing the basic designs for the great clipper ships of the 1840s.

aids to navigation

Beyond the ships themselves, several innovations helped support maritime enterprise in the early national period. The first lighthouse had been built in Boston Harbor in 1716, but by the time of the Revolution only fifteen lights had been built on the entire coast. In the following four decades, lighthouse construction efforts intensified, extending inland to the Great Lakes in 1819 and southward to the Gulf Coast in the 1820s. Experiments with wicks and lenses increasingly magnified the whale-oil lights, and eventually resulted in the 1840 invention of the powerful and effective fresnel lens.

In the 1750s Englishman John Harrison solved the problem of determining longitude by developing a marine chronometer capable of keeping precise time. The clocks, however, remained too expensive for most mariners, and a ship's position was most often determined by a complex set of calculations based on astronomical observations and published tables. The sextant, invented in 1757, was in popular use by 1800 and provided mariners with much more precise astronomical measurements than had been previously available. The tables used in computing longitude were published in British marine almanacs starting in the mid-eighteenth century but were filled with errors. In 1800 Nathaniel Bowditch, a Salem shipmaster, corrected the eight thousand errors in the British tables and published the results in 1802 as The New American Practical Navigator. Just six years earlier, another Massachusetts ship captain, Edmund Blunt, published The American Coast Pilot, which contained instructions for entering ports along the eastern seaboard. Both texts quickly became the essential technical works for American navigation; their publication, with annual updates, has continued to the present day.

steam power

The first commercially viable steamboat, the Clermont, was built by Robert Fulton in 1807 for use on the Hudson River. By 1815 Fulton had fifteen steamboats in operation, Nicholas Roosevelt had run his steamboat New Orleans from Pittsburgh to New Orleans, and twenty steamboats were making regular trips on the Ohio River. Steamboats burned an enormous amount of timber, which had to be stored onboard, thus adding to the boat's weight and using up valuable space. In 1817 the Chancellor Livingston was fitted to burn coal as fuel, and by the mid-1820s most steamboats were equipped to burn both wood and coal. Using the much more compact coal meant a savings in space and weight that allowed steamboat designers to add not only more passengers and cargo, but amenities like dining saloons and private cabins.

Steamboats were great commercial successes on the inland waters, but it was only after the move to coal that ocean steamers could provide services to compete successfully with sailing packets. In 1819 the sailing ship Savannah was retrofitted with a steam engine and paddle wheels and was the first ship to cross the Atlantic partly under steam. Later the same year the Robert Fulton became the first steam vessel built specifically for ocean travel. Steam was still unreliable, though, and most of the seaborne steamships retained masts and sails. The steamship President, built in 1829, was the first to abandon sails entirely, but most steamships combined sail and steam power through the 1880s.

naval vessels

The navy also experimented with steam, hiring Robert Fulton to build the Demologos in 1814. Prior to that time developments in naval technology had largely been limited to design improvements that balanced the weight of guns, structural integrity, and speed. One advance had been the invention of the carronade, a small cannon that could throw a fullsize shot, but with limited range. The carronade was invented in the 1770s and quickly adopted by naval shipbuilders, as it allowed the clustering of firepower at the vulnerable bow and stern of the ship. Fulton's Demologos was a paddle-wheeler equipped with five-foot wooden sides for defense and twenty guns for offense, but was so heavy that it could only make five knots under full steam. Overweight, underpowered, and propelled by vulnerable above-water paddlewheels, the steamboat remained unviable as a naval craft until improvements in boiler technology and the replacement of paddle wheels with screw propellers in the 1840s cleared the way for the development of a steam-powered navy.