UNSUNG HERO

A 1947 US MOTORS DIESEL GENERATOR ON A HISTORIC SHIP

- JIM ALLEN

Deep in the engine room of the SS James M. Schoonmaker lives this unobtrusive diesel generator. It’s a US Motors model D50D 50KW set powered by a 529 cubic inch Hercules DXRC indirect-injected diesel. The generator makes 50 kilowatts of DC power (400 amps at 125 volts) and powers the 6.5-ton deck hatch crane, as well as a DC-to-AC motor generator. The radiator may seem strange to you, given that most marine installations involve using raw water cooling (with or without heat exchangers). This generator was not designed to run for long periods and the radiator setup reduced installation costs. Given the engine room is well ventilated because of the nearby boilers and steam turbines, it’s not likely running it for an extended period would be much of an issue anyway.

Diesel generators have many uses aboard a ship. Usually they have a fairly central role, with devices of many types being powered by the electricity produced. When you go back in time to when steam ruled, diesel generators were less central and sometimes used only for a single purpose. Case in point; the SS Col. James M. Schoonmaker, a Great Lakes ore boat that was built in 1911 and operational through 1980.

Ok, right now some of you ex-mariners are screaming, “A 617 foot long vessel is not a boat, you dufus!” First, the guy writing this is a former U.S. Army mariner, so he knows the difference between a ship and a boat, but he had to learn that mariners on the Great Lakes use different terminology... and now you do. One; vessels on the lakes are called boats, regardless of size. Two; they measure speed and distance on the lakes in statute miles, not nautical miles. Go figure.