Hi Mike,
Actually, the design of the machinery plant for Oceanic III was heading towards being a diesel-electric plant -- something like 47 or 48 diesel/alternator units, with the power being split amongst four shafts being driven by electric motors. If this ship had been built, then just like the Britannic III and Georgic II, the only steam generated on board would have been from exhaust waste heat boilers, used to produce steam for heating, domestic fresh water distillation and hotel services. (Steam from waste heat can also be used to run turbo generators for ship's lighting and ventilation while at sea; then, in port, the load is switched over to diesel generators.) Remarkably forward-thinking, this machinery plant; in a way, the marine engineers at H&W, who were pioneers in the application of diesel technology to ship propulsion, were predicting the main machinery of passenger ships some 65 to 70 years in the future.
Regards,
Scott Andrews