Well. Not quite. But catchy, eh?

In 1968, the keel was laid for the the USS Nimitz, CVN-68, part of a new group of 1,092′ aircraft carriers. The ship was named for Chester W. Nimitz, former Fleet Admiral/Chief of Naval Operations. I am not writing a history of Nimitz, there’s plenty of that online already!

In 1965, the proof of concept for the Nuclear carrier was cemented in the success of the Enterprise (CVN-65). Two more traditional (oil fired – steam turbine) powered carriers were built after the Enterprise, the America (CV-66) and John F. Kennedy (CV-67) commissioned in 1965 and 1968 respectively.

Aircraft Carriers are no simple ships, it would be another 5 years before the Nimitz would be commissioned in the spring of 1975. The ships would pack a massive 260,000 horsepower power plant, producing steam from a pair of reactors, which in turn fed a quartet of steam turbines.

Even with all of that power at hand, ships need emergency power generation capabilities. This would be handled by the Electro-Motive Division.

EMD Brochure – Click for larger.

The fleet of carriers, grew from the original 3, to 10 in 3 different sub-classes. While we know for sure the 1st 6 had EMD-supplied emergency gen-sets, it is uncertain if the last 4 did as well, as my records do not go that late.

The generators chosen would be Turbocharged EMD 16-645E5N engines. These engines drove 4160 volt, 2000kW generators, and each ship had 4 of them! In order to be utilized in an Aircraft Carrier, the engines were required to go through some pretty scrutinous testing for the US Navy, something General Motors was well accustomed to at this point.

EMD photo, VDD Collection – Click for Larger

In order to do this, EMD made a gigantic, movable test stand! The engines needed to be tested in overload situations and at various angles to mimic conditions out in the ocean, as well as shock loading in case of battle conditions. In the photo above, an EMD engineer is as work testing one of these engines with it leaned over to the side.

EMD photo, VDD Collection – Click for Larger

All 10 of the Nimitz class carriers are still in service, however the Nimitz is currently out for her last deployment. The Nimitz is scheduled to begin the long decommissioning process in 2026.

It’s worth noting the previous three carriers, Enterprise (CVN-65), America (CV-66) and John F. Kennedy (CV-67) also had EMD generators. Each ship had 16-567C engines with 1000kW generators: Enterprise had 4, the others had 3 each. The engines in the Enterprise were ordered and shipped under Cleveland Diesel, one of their last large projects before being absorbed into EMD.

Additional Commentary by Jay Boggess

I worked at EMD from 1981 till 2004, starting off in the AC Design Group of the Electrical Rotating Department. I remember some of the Nimitz-class gen-sets being assembled in the EMD shop, probably around 1985. 

I can see in my mind’s eye 40 years ago, the General Electric AC generators sitting on the EMD hi-bay floor, awaiting installation.  2000 kW, 8-pole 4160 Volts, 60 Hz.  Water to air cooler. No photos from that pre-iPhone era, but here’s a pic of a smaller GE generator installed in the carrier Forrestal:

GE figure from 1954 CDED 450 Volt 1000 kW instruction book – Jay Boggess Collection

I remember how the Nimitz GE generator was so physically larger than an EMD locomotive generator of the same kilowatt capacity (I learned later why that is – it has to do with the Navy’s requirements for the AC generator’s self-regulation – to meet the requirement, the generator has to get bigger and heavier).

The special skid for the 15-degree fore-and-aft list test kicked around the LaGrange back yard for some time.  Fifteen degrees may not sound like much, but it translates to about 6 feet at the far end of the gen set.

While VDD’s records do not extend to the latest Nimitz-derivative nuclear carrier (John F Kennedy CVN-79 under construction), I suspect the EMD 16-645E5N engines are there.  Navy Hi-Shock qualification tests are rigorous, and I can’t imagine any other diesel engine manufacturer attempting to get into that market for just a small quantity of engines.

Finally, Cleveland Diesel built 3 sets of 1000kW emergency generators for 3 Forrestal-class supercarriers in the 1950s – Forrestal (CVA-59), Saratoga (CVA-60) and Ranger (CVA-61).  All three are now razor blades.