The Curious History of Electric Ship Propulsion

27443In 1929, USS Lexington (CV 2) used its electric propulsion system to power the city of Tacoma, Washington, during a local energy crisis. Photo courtesy of Tacoma Public Library.

By Colin E. Babb

For more than a decade, naval engineers and others have been calling for the introduction of the “all-electric” ship in the US Navy. With the increasing electrical needs of communications and radar systems and the rise of entirely new energy-hungry technologies such as lasers and electromagnetic railguns, proponents argue that warships of the near future will demand electric-drive systems that can distribute power among propulsion, communications, weapons, and other ship systems as needed. While the systems needed to power ships are more sophisticated than ever, the idea of the electric ship is, in fact, an old one, and for much of the 20th century the Navy had at least several and sometimes numerous ships powered by electric drive.

What distinguishes electric propulsion and all-electric ships, in the simplest terms, is that the machinery for generating power and the machinery for propelling the ship are not mechanically connected. For the first century of steam propulsion on ships, most engines were joined directly to propellers or paddlewheels through the use of rods and pistons—all falling under the general category of reciprocating engines. Very early in the 20th century, steam-driven turbines began to appear (HMS Dreadnought, famous for the novelty of its all-big-gun armament, also happened to be the first major warship to receive this new type of propulsion in 1906). This engine consisted of a high-revolution turbine connected by reduction gears to the more slowly spinning propeller. In an electric drive, the power-generating turbine is connected only electrically to a separate motor or motors, each of which drives a propeller. The most important advantage of such a system is that each component can operate at maximum efficiency—the turbine can spin at consistently high revolutions, and the propeller can be set at the most efficient revolutions for any given speed or situation. In addition, there is no need for a long propeller shaft, freeing room in the ship for other machinery.

A central figure in the history of the Navy’s adoption of electric drive is William Le Roy Emmet, a graduate of the Naval Academy Class of 1881 and a longtime engineer at General Electric. Emmet’s Navy career was cut short in 1883 after his initial post-academy cruise because of a new law that severely limited the number of officers in the service. Forced to find employment elsewhere, Emmet drifted into electrical engineering and was soon building electric motors for urban rail projects across the Midwest. Working at Edison General Electric and then the General Electric Company after it formed in 1892, Emmet was involved in many of the company’s biggest early ventures, including building turbines for the first major hydroelectric power plant near Buffalo, New York. A brief return to naval service during the Spanish War of 1898 reintroduced Emmet to the “New Navy,” coinciding with General Electric’s turn toward steam turbine projects that eventually would be shopped to the Navy.

William LeRoy Emmet

William Le Roy Emmet (1858-1941) designed the Navy’s first electric propulsion systems. Image courtesy of Philip Hone Williams.

 

In 1908, according to historian William McBride, Canadian inventor Reginald Fessenden submitted a proposal to the Navy for a turboelectric drive that was rejected. Fessenden, however, was allowed to contact other companies that might be interested in the idea. Emmet at General Electric proved enthusiastic about the possibility of turboelectric drive and formulated detailed drawings from Fessenden’s proposal. Emmet outlined his ambitious plans in a lengthy paper in the Transactions of the Society of Naval Architects and Marine Engineers in 1909. Describing two systems—the first being a hybrid electric/steam turbine combination, the other a pure turboelectric drive—Emmet advocated for the installation of electric drives in the Navy’s battleships, even though he admitted in practice they had never been tested on anything larger than firefighting boats in Lake Michigan. In Emmet’s hands, the electric drive acquired a significant ally in Secretary of the Navy George von Lengerke Meyer. Leveraging an endorsement of turboelectric drive from the Navy’s General Board, Meyer authorized the installation of electric propulsion in one of three new coal-hauling colliers that began construction in 1910.

In an attempt to determine the most efficient and effective of the three types of propulsion, the Navy decided that each of the three colliers would have a different engine. In addition, installing new equipment on these noncombatant vessels would avoid the risky step of evaluating them on expensive battleships. The three colliers were: USS Cyclops (AC 4), which received reciprocating engines; USS Neptune (AC 8), which received steam turbines; and USS Jupiter (AC 3), the last of the three to be built in 1912, which was equipped with turboelectric drive. The decision was prudent as well as practical—although they were auxiliaries, the colliers’ size (20,000 tons) was comparable to the battleships being laid down at the same time (22–26,000 tons). Once Jupiter underwent trials in 1913, the ship proved to be a success and, according to a report by chief engineer S.M. Robinson, exceeded General Electric’s economy predictions over the rival engines by 18 percent. Emmet also triumphantly declared in his own report on the trials that, “If my first design for a warship made over four years ago [in 1909] had been accepted by the Navy Department, the vessel produced would have been very greatly superior in respect to economy, reliability, weight, simplicity, and cruising radius to any ship now afloat.”

Meyer’s successor, Josephus Daniels, gave Emmet the opportunity he was looking for in 1915 by ensuring that electric drive would go in the battleship USS New Mexico (BB 40), the first major warship to be electrically driven. In 1916 and 1917, however, electric drive would be at the center of a major debate between the Navy and the nation’s shipbuilders as both groups prepared plans for a host of new battleships proposed under 1916 legislation intended to make the Navy “second to none.” One of the interesting features of the controversy was that it pitted the Bureau of Steam Engineering as the proponent of (ostensibly more progressive) turboelectric propulsion for the Navy’s latest battleships, against many of the nation’s biggest shipbuilders, which lobbied against the new technology as a threat to traditional propulsion (and higher profits). Initially skeptical of electric drive, the bureau was won over by Jupiter’s success. Shipbuilders, however, balked at the increased costs of producing the new drives, which were more complex than steam turbines or reciprocating engines.

General Electric Ad

In 1919, General Electric touted its expertise in electric propulsion with a full-page advertisement in the Cornell Alumni News about USS New Mexico (BB 40).

With the help of vocal bureau spokesmen and, according to McBride, a host of luminaries such as Nicola Tesla who favored electric drive, public opinion swung toward approval of the new system and opposition from industry abated. Five other battleships—USS Tennessee (BB 43), USS California (BB 44), USS Colorado (BB 45), USS Maryland (BB 46), and USS West Virginia (BB 48)—would receive electric drives over the next five years, as would the battlecruisers USS Lexington (CC 1) and USS Saratoga (CC 3), which would be converted midway through their construction into aircraft carriers. (Consequently, from 1920—when Jupiter was converted into the first US aircraft carrier, USS Langley [CV 1]—until 1934, all US aircraft carriers had electric drive.)

The first generation of electric drives, however, never proved in practice as radically more efficient than their mechanical rivals as their proponents had theorized, and these were the last major ships to receive electric systems. Lexington proved the versatility of electric drive, however, when in late 1929 and early 1930 it provided power for the city of Tacoma, Washington, during a drought that had depleted the town’s power-generating reservoir.

Electric drive would see longer life in smaller vessels, such as the 102 members of the Buckley (DE 51) class of destroyer escorts built during World War II, as well as several classes of fast transports. Two submarines—USS Tullibee (SSN 597) and USS Glenard P. Lipscomb (SSN 685)—also had electric drives (the latter was the last major ship in the US Navy to use electric drive before the modern era). It was in the merchant service, especially cruise ships, where electric drive would continue on to the present day. First appearing in SS California (later Uruguay) in 1927, electric drive has been a common feature of cruise liners for more than a generation.

The all-electric ships of today are altogether more complex than the ships of a century ago, which had relatively few electrical systems beyond propulsion and rudimentary communications and hotel requirements. The first generation of ships also did not need pulsing—the storing and releasing of high volumes of energy in short timespans. But as the history of electric drive suggests, sometimes good ideas take time to develop fully. In this issue are articles that describe current efforts to make the modern all-electric ship a reality, as well as outline other projects under way in the area of power and energy.

About the author:

Colin Babb is a support contractor serving as the historian for the Office of Naval Research and managing editor of Future Force.

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