EMD 16-338 pancake engine

The EMD 16-338 was a lightweight, compact, high speed two-stroke diesel engine that Electro-Motive Diesel designed in the 1940s and 1950s as one of its so called pancake engines, a type built around an aluminum block and a vertical crankshaft. Its sixteen cylinders sat in an X pattern of four layers of four cylinders, each with a bore of 6 inches and a stroke of 6.5 inches, and it was mechanically injected and supercharged by a Roots blower. It developed 1,090 brake horsepower, or 810 kilowatts, at 1600 revolutions per minute, with a generator on the bottom of the crankshaft, and the whole unit weighed just over eight tons. Because it stood only about 13.5 feet tall and 4 feet wide, four of them fitted in a submarine engine room only 22 feet long. The United States Navy used it in the Tang class submarines and the research submarine USS Albacore, where fluids running down into the generator and a lack of spares made it unreliable, and the Navy replaced it in the Tang class with Fairbanks-Morse opposed piston diesels.