Lebby, Nathaniel H
By June 1858 Lebby’s suction pump had been used to remove some 145,000 cubic yards of material, an unprecedented dredging achievement.
Inventor. Lebby was born in Charleston on August 22, 1816, the son of William Lebby and Frances Scott. He conceived of the mechanism for the world’s first hydraulic suction dredge, which became the standard method of modern dredging. The device was first employed in the dredge boat General Moultrie in the late 1850s to deepen a new channel through the Charleston harbor bar.
Although it provided the city with an active and prosperous port for almost two centuries, Charleston’s harbor had a serious drawback at its mouth–a shifting barrier of sand and debris that lay between one and three miles offshore. As ships got larger, they drew increasingly deeper drafts, which made the problem of the bar more acute with each passing decade. By 1852 the U.S. Coast Survey found that shoaling in the main channel through the bar had reduced its depth to less than eleven feet at low tide, down from an estimated thirteen feet in 1780. As a result federal, state, and local officials began looking for ways to deepen the channel.
By this time Lebby was employed by the South Carolina Railroad. In 1852 he had been awarded a patent for a “water raising apparatus,” a steam-driven pump that found frequent employment on rice plantations to flood and drain fields. When in operation, his pumps discharged sizable amounts of mud, sand, and even rocks. Lebby believed that a similar pump would pass through dredged material as well. His working model for a dredge that used a pump to suck up materials through a pipe impressed Captain George Cullum of the U.S. Corps of Engineers, who had assumed charge of public works in the harbor in 1855. Lebby’s machine was housed in a New York–built dredge boat, which, christened the General Moultrie, went into service in early 1857. The results were spectacular. By June 1858 Lebby’s suction pump had been used to remove some 145,000 cubic yards of material, an unprecedented dredging achievement.
Patent and mechanical drawings for the dredging apparatus do not survive, but Captain Cullum recorded a description of Lebby’s apparatus in 1857: “a large centrifugal pump six feet in diameter, revolving on a vertical axis, to which an iron 19” (diameter) suction hose is attached, its lower, or bell-shaped, end resting on the bottom of the channel. The pump is placed in the center of a powerful propeller under the deck in the hold of the vessel and is powered by a steam engine, which is supplied by steam from the propeller boiler.”
Lebby received three additional patents after the Civil War: one in 1867 and one in 1869, each for a “Centrifugal Pump”; and a third in 1870 for an “ore washing machine.” He never married. Lebby died of consumption in Charleston on February 11, 1880, and was buried at Magnolia Cemetery there.
Bonds, John B. “Opening the Bar: First Dredging at Charleston, 1853–1859.” South Carolina Historical Magazine 98 (July 1997): 230–50.
Comfort, Jan. “South Carolina Inventors and Inventions, 1790–1873.” South Carolina Magazine of Ancestral Research 25 (summer 1997): 123–36.