I wonder if Oceanic's possible diesel power plant would have been successful? The scale of the engines would have been far above anything else that put to sea at that time. (Actually, for about 50 years!)
I have read that the choice of power for Oceanic was never definitely decided, except for the fact that it would be electric. (Source: Power of the Great Liners) It is possible that White Star would have opted for a turbo-electric power system in the end. This would have lessened the development risk and had several advantages. (Full astern power available without the need to fit astern turbines, the ability to take a turbine off line and still keep all screws running, etc.)
If White Star had just managed to get Oceanic III to the launching stage then it is quite likely that she would have been finished and run with the Queen Mary. There would have been no need to build the Queen Elizabeth. An interesting what if........
Why did Cunard not build Oceanic? That is simple-Cunard was the majority sharelholder in Cunard White Star and had no interest in the White Star side of the company. Cunard was the surviving company, not White Star.
If Oceanic III had been built with diesels, it might have been a disaster. I am not sure the technology was mature enough for a high speed motorliner.
It was simpler than that Brent. Oceanic had been scrapped by 1930, but Cunard and White Star merged in 1934. The merged company had a 1000ft liner mostly complete at John Brown's. They weren't about to start building Oceanic again
As to James' question about whether she would have been a bit of liabilty. Personally I doubt it. The Normandie and Queen Mary showed that the market was ready for liners of this size, and H&W had been ready to build one for years. True, a diesel installation of the required size had never been tried before, but the Royal Mail group had several succesful intermediate diesel liners. Remember Britannic lasted until 1960 using late 1920's diesels.
I agree that the time was right for such an experiment. Electric engines worked on the "Normandie" and while she had turbine engines to power them they could have easily been geared to diesels - and more economically so. HAPAG built the "Patria" with diesel-electric propulsion in the late 30s, so Oceanic III would been a little earlier than that. There were already smaller ships and submarines powered with this sort of propulsion as early as the 10s and 20s. Why should this not have worked on a grander scale?
>>Why should this not have worked on a grander scale?<<
Ultimately it did. However, you need to keep in mind that shipowners tend to be a bit of a conservative lot and they don't try new things lightly. Especially with ships that are large and expensive. If the plan was to stick with turbines and/or reciprocating engines, it was because these were proven systems.
If they were to gamble on something new, it would be understandable that they would want to be certain that it would function reliably.