Modern Tugboat Engines

Electro-Motive Diesel (EMD)

Models 645 and 710

Above: A Cutaway View of the EMD 16-645 Marine Diesel Engine



Article by Preston Cook

The Electro-Motive 645 and 710 series diesels are used in many modern tugs as well as a wide variety of other marine propulsion and generating applications. The 645 series engine has a cylinder bore of 9-1/16 inches and a stroke of 10 inches, and was built in 8, 12, and 16 cylinder "normally aspirated" (roots blower) configurations and in 8, 12, 16, and 20 cylinder turbocharged versions. The 710 series engine also has 9-1/16 inch bore, but with 11 inch stroke, and was introduced in the 1980s as an enhanced fuel economy and reduced emissions engine. The 710 is only built in turbocharged versions, with 8, 12, 16, or 20 cylinders, and has been produced with mechanically controlled fuel injection as well as electronic injection systems. Both engine series were in production simultaneously from 1983 through the late 1990s, the 645 series has now been discontinued.

The 645 and 710 series are the successors to the EMD 567 series engines, first built in 1938, which were developed by a team of talented design engineers at the GM Research Laboratories under the direction of Charles F. (Boss) Kettering. The engineer who had the greatest influence on the design and development process was Charles Kettering's son Eugene, who joined Winton Engine when GM acquired the company in 1930. In 1936 he moved to Detroit to work on the development of the 567 engine, then moved to EMD in 1938 when the engine went into production. He became Chief Engineer at EMD in 1948, progressed to Director of Research in 1955, and became Research Assistant to the General Manager in 1958. He resigned in 1959 to take over management of foundations created by his father, and passed away in 1969.

The 567 engines were used in many railroad applications and are still quite common in marine service. They all have an 8-1/2 inch cylinder bore with 10 inch stroke. The 567 series underwent a major design change in 1953 under the direction of Eugene Kettering ("Boss" Kettering's son) that strengthened the engine crankcase allowing higher power outputs, while still maintaining parts interchangability with the earlier engines. The 645 engine introduced a greatly strengthened crankcase along with a bore increase to 9-1/16 inches. The 567 crankcase went out of production following the introduction of the 645 series engines in 1966, although a few late 567's were built in 645 crankcases to satisfy the military's "proven product" requirement for diesel engines.

Electro-Motive dates back to the 1920s, when it was established as a designer of gas-electric railroad passenger cars in Cleveland, Ohio. It was acquired by General Motors in 1930 along with the neighboring Winton Engine Company. It became the Electro-Motive Division of General Motors (EMD), a major builder of diesel locomotives and marine engines. Electro-Motive is now owned by Progress Rail, a subsidiary of Caterpillar, and EMD trademarks and copyrights are now the property of Caterpillar.


Above: A 16-645 Marine Engine at La Grange in the 1960s. Notice the deep sump oil pan required on most marine installations to allow for the rolling of the vessel when operating in heavy seas.


Above: Following its use in testing, the First EMD 710 Series Engine was painted in Pontiac GTO metallic blue and was used for many years as a show engine. When it was on display at boat shows the oil pan was usually not shown, since it really was a locomotive engine, not a marine engine, and did not have a deep sump oil pan.


Above: Electro-Motive had a curious history in the marine industry. The EMD engines were originally designed for railroad locomotive use, while Cleveland Diesel Division of GM built the marine diesel engines. At the beginning of World War Two, there was a shortage of marine engine building capacity, and EMD engines were installed in three U.S. Navy fleet tugs. The installation was highly successful, and resulted in their being awarded the contract for more than 2400 engines for U.S. Navy LST vessels (as shown in the background above). In the postwar years Electro-Motive took market share away from Cleveland Diesel and eventually absorbed them. Cleveland Diesel rights and trademarks were sold by GM to Hatch and Kirk of Seattle, Washington in 1977.


Above: An EMD 20-cylinder 645 series engine is prepared for installation at a shipyard. Sitting next to the engine is the Falk reverse reduction gear.


Above: Two EMD 20 cylinder 645 series marine engines are show in the engine room of a vessel that has a combining reverse reduction gear, both engines drive one propeller shaft. The 20-645 was a very popular marine engine for installation in new construction vessels from its introduction in 1966 through the release of the subsequent EMD 710 series engines in the 1980s.




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