The Overlooked Origins of the Jet-Powered Boat

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A replica of James Rumsey’s steamboat in front of a mural showing the crowd of onlookers on the wharf on the date of the public trial in December 1787.
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Portrait of James Rumsey, probably painted by George W. West.
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The James Rumsey monument erected in the early 1900s along the bank above the Potomac River at Shepherdstown, W. Va., by the Rumseian Society.
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Live Stream is allowed into the Steam Cylinder by the Control Valve and pushes up the Steam Piston. The Connecting Rod pulls up the Water Piston, thus drawing water in through the River Valves into the Water Cylinder. At the top of the stroke the Control Valve is flipped to start the thrust, or vacuum, stroke.
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When the Control Valve is flipped, the Steam Cylinder is connected to the Condenser, which condenses the steam, creating a vacuum. Because of the vacuum in the Steam Cylinder, air pressure now pushes the Steam Piston and Water Piston down, forcing water out of the Water Cylinder, through the Truck Line and out the stern. By reaction, this mass of water thrown backward propels the boat forward, in the same way as a jet or rocket. At the same time, more water is pumped into the Water Tube Boiler by the Injector Pump, and condensed water and trapped air are pumped out of the Condenser by the Air Pump. Notice the water passing through the Trunk Line Flapper Valves during the Steam Stroke? These allow water from the Thrust Stroke to continue moving out the Trunk Line during the intake of new water through the River Valves.

Look across any fairly large body of water on a warm summer day and you’ll see the high plume of water that marks the passage of someone on a jet ski. (Jet Ski is a registered brand name of Kawasaki Motors, Inc., but seems to have been adopted as a generic name for all personal watercraft.)

Jet boats and Jet Skis are all the rage these days; besides the popular one- or two-passenger Jet Skis, passenger and car ferries, excursion boats, and other small to medium-sized, high-speed boats for myriad uses have been developed. The South African navy has four 3,700-ton jet-propelled frigates, and the amphibious assault vehicle that was being designed for the U.S. Marine Corps a few years ago (and canceled in 2011 by then Defense Secretary Robert Gates as it was too expensive) was to be water jet-propelled while in the water.

Sir William Hamilton is credited (in the 1950s) with developing the jet boat to ply the shallow rivers of his native New Zealand where conventional propellers often struck bottom. However, a modern fun seeker skimming over a lake at high speed on a jet ski would undoubtedly be astonished to learn that the first jet-powered boat was powered by a steam engine. And even more amazingly, it was first launched in 1787!

A chance meeting

In 1783, after the end of America’s Revolutionary War, Gen. George Washington resigned his commission and retired to Mount Vernon and his farm. Washington owned large tracts of land in western Virginia and Kentucky and dreamed of opening a waterway to these lands using the western headwaters of the Potomac River, which, of course, flowed past Mount Vernon’s doorstep. In September 1784, Washington set out on a trip west to explore the possibilities of the upper Potomac.

He stopped at Bath, Va. (now Berkeley Springs, W. Va.), to “take the waters” and stay at the inn operated by 31-year-old James Rumsey. A personable man, Rumsey charmed the general and showed him a working model of a mechanical boat he had devised. The little boat had a paddle wheel in its center that was connected by a crank to a long pole outside each gunwale. Rumsey placed the model into a fast-running little stream and the current spun the wheel, which moved the poles alternately against the stream bottom. Before Washington’s skeptical eyes, the poles pushed the boat upstream against the current using only the power of the stream itself!

Much impressed, the general saw the possibilities of the mechanical boat in Western trade and gave Rumsey a signed testimonial that he later used to extract monopoly rights from Maryland and Virginia, as a federal patent office had not yet been created.

Back to the drawing board

A full-sized pole boat was built and, under the supervision of Rumsey’s brother-in-law, Joseph Barnes, made its trial run in the Potomac in March 1786. The boat carried 3 tons of stone and numerous passengers and succeeded in moving upstream some 200 yards. Rumsey wasn’t happy with the boat’s performance, however, and concentrated on his steamboat.

But Rumsey, then living in Shepherdstown, Va. (now West Virginia) along the Potomac River, continued to work secretly on the boat. The few townsfolk who knew what he was doing scoffed and dubbed him “Crazy Rumsey.”

To save weight, Rumsey invented a pipe boiler and had to build his steam engine himself. It was based on the early single-acting engines developed by James Watt in England. The steam and pump cylinders were stacked and shared a common actuating rod. Low-pressure (7 psi) steam from the boiler was let into the steam cylinder forcing the piston to rise. The pump piston went up with it and drew river water into the cylinder through one-way valves. The steam was quickly condensed, creating a vacuum inside the steam cylinder, and the piston was forced down by the outside air pressure. This pushed the water out of the pump, through a tube and out an orifice at the stern of the boat creating a force that propelled the boat forward.

In September 1787, Rumsey and Barnes tried the thing. Barnes wrote: “The boat moved up the river against the current with about 2 tons on board, besides the machinery, at the rate of 2 mph.” Then the heat of the boiler softened the solder in the pipe joints and several burst; Rumsey lost steam and had to row to shore.

“She goes!”

After boiler repairs, Rumsey scheduled a public trial for Dec. 3, 1787, which turned out to be an unseasonably warm day. A huge crowd gathered (including Revolutionary War Maj. Gen. Horatio Gates, who had a plantation nearby) most of whom expected to see Rumsey’s contraption fail.

Many of these folks wanted to go on board for the trip (if there was to be one), but Rumsey decided to take only a few of the ladies. These worthies were helped onto the boat and seated, Rumsey checked the fire in the boiler and a Capt. Morrow took the helm. The vessel was pushed away from the wharf, where Rumsey started the engine and the boat moved into the middle of the river, turned and began to move upstream.

Although it may or may not be true, local lore has old Maj. Gen. Gates throwing his hat into the air and exclaiming, “She goes, by God, she goes!” while the rest of the crowd cheered. After going about half a mile, the boat turned and went downstream past the wharf where it again turned and returned upstream, running back and forth for two hours.

Reaching a bitter end

Unfortunately, Rumsey had to sell the hull of his boat to pay pressing debts, although he kept the boiler and engine. In 1788, he went to Philadelphia to raise money and while there, he conceived the idea of going to England to get a patent there and to raise money, as he was chronically short of funds to improve his steam boat.

Rumsey endured years of ups and downs while trying to raise money in England and France. He amassed massive debt (requiring him to hide out from the sheriff on occasion) but made very little progress on his jet boat. On Dec. 17, 1792, Rumsey gave a lecture on hydrostatics to the mechanics committee of the Royal Society of Arts in London. Immediately after, he suffered a stroke; he died the next day.

That was the end of water jet-propelled boats until Sir William Hamilton 150 years later. Robert Fulton, whose North River Steamboat of Clermont first sailed the Hudson River (propelled by paddle wheels, not jets) 20 years later in 1807, is known today as the man who invented the steamboat, while James Rumsey is forgotten, except by the people of Shepherdstown, W.Va. FC

Sam Moore grew up on a farm in western Pennsylvania. He now lives in Salem, Ohio, and collects antique tractors, implements and related items. Contact Sam by email at

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