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I sailed on all five of these vessels (GT Washington, Oregon, Colorado, Louisiana & Arizona). They were delivered over a two year time period from Dec 75 to Dec 77 by FMC (now Gunderson) in Portland, Oregon. There were plans for a sixth (Nevada) but the order was canceled, despite the ship being at least partially constructed. The Oregon and Louisiana were dedicated to carrying crude, while the Arizona and Colorado were product carriers. The Washington could carry both.

The Main Gas Turbine (MGT) powered the entire ship under normal conditions. It was an 8.8MW GE Frame 3 model... not a marinated aeroderivative such as the LM2500. They burned diesel, and to the best of my knowledge there was never any experimentation with heavy fuel. It would have been impossible and the turbine needed to run on clean oil to keep the compressor turbine blades clean.

The Auxiliary Gas Turbine (AGT) was indeed a Ruston. It was located on the port side, one deck below the main deck. The joke about these units was that the control panel meters generally showed more start attempts than running hours. They were, in my mind, highly unreliable. We used them generally only when in port and we needed to shut the MGT down for maintenance, about once per month. Normally we kept the MGT on. There was a strange method where you could, in an emergency, run the propulsion motor at a reduced speed on the AGT in the event the MGT was down at sea. I saw it done often, mostly as a test.

When I first started sailing on the vessels in the early 90's, the weak link was the original GE control systems for the MGT. They were getting old, weren't very well "marinized" and were the source of too many incidents of losing the main engine. Cuing a radio near the units would trip the MGT. Around 92 through 94 the control systems were upgraded to a solid-state PLC-type system. Most times trouble-shooting the MGT meant connecting a laptop to the controller. Lots of on the job learning.

The MGT had a very interesting control methodology. The MGT was twin-shaft, with the power end turning at a constant speed to produce 4160V at 60hz. The propulsion motor was a large, synchronous motor that ran at a constant speed of 100rpm. Speed (and direction) of the vessel was controlled by a CPP - controllable pitch propeller. When the prop motor was started, the lights would briefly dim, almost go out completely, then slowly come back on as the main engine responded to increased load.

The vessels also had a CAT diesel generator that acted as an emergency generator, but since it was located on the weather deck, was technically insufficient in that role in the eyes of the USCG. So there were two large 24v battery banks that powered emergency lighting and a few other essentials.

The GE frame 3 turbines were quite robust. As I recall, the "weak" area of the turbine unit itself was likely the compressor turbine blades which bore the brunt of the combustion gas. Every PO period some part of the turbine case would be cracked open for inspection.

Regarding profitability, it's hard to say. The vessels, particularly the Arizona, had fixed runs. Some acted as a pipeline connecting the two Chevron refineries in CA (Richmond and El Segundo). I think Chevron was willing to pay a price to keep a few tankers they could put their hand to immediately if necessary.

The strangest thing about these ships was the "PCC" - Port Control Center. It was basically a combination Engine Control Room and Cargo Control Room. In port, the engineer and mate on watch sat across a desk from each other, looking at two control panels that were behind the other person. This was located on A deck.

The ships weren't regularly traded outside the US, but I've been on one them in Canada, Mexico (both coasts), through the Panama Canal as well as Alaska and Hawaii.

Yes, the main engines required far less maintenance than a diesel, but I wouldn't say the vessels were low maintenance by any means. Plus, the culture on Chevron's vessels was that the engineers handled all on-deck repairs and maintenance (there were no pumpmen), so we were busy 12hrs/day.

Hope this helps...
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