As a long-distance sailor, I have had more than one encounter with cargo ships that supposedly were fully crewed. In a couple, I could raise no one on the radio so was uncertain about their intentions. Being smaller (35') and more maneuverable, I took what evasive action I hoped was best/ Fortunately, the unresponsive vessels maintained course and speed, as expected under autopilot.
There is a maritime regulation about maintaining a proper lookout at all times. But maybe that doesn't apply if you're big enough and don't care.

Energy requirements for crew quarters is an insignificant proportion of fuel used by the ship to travel.
If they are serious about energy saving we would see the mechanically deployable sails that were proposed some year back that claimed beyond 20% reduction per trip with ship engines status quo.

An open invite to modern-day pirates.....!

Surely, a more sensible solution to shipping costs is to cut out all these global movements of goods and produce in the first place. Let's get back to not having strawberries and other such items in mid winter just because it happens to be summer on the other hemisphere. When they do become available locally, they will taste so much the better for not being a common item in our diet.
Let's make goods where they are to be used. I.e. let's employ local people at local rates under local laws instead of exporting the jobs to countries that have poor labour and emissions controls and an attitude of 'to hell with people and planet'.
At least Rolls Royce recognises that we have extracted all the cheap oil and can see that prices will rise at the front end, which will lead to shortages in supply or retail prices will rise with all that that means for us and our way of life.
The oil supply parts of this article need to be read in conjunction with the Our Finite World's blog and the climate change component read in conjunction with Professor James Lovelock's latest work and the Nature Bats Last blog.
Afterwards, you could be forgiven for thinking that the only sensible option is to 'eat, drink and be merry, for tomorrow ...'

Obviously this is the way of the future. Actually, they would be BETTER than a "manned" ship, as they would be driven utilizing a multitude of devices. (Camera's, sonars, radars, GPS, alert systems, and of course "anti-boarding" devices…) Yes, there are those against the idea, but then, they are probably those who opposed the use of "unmanned" aircraft…. The only thing I see as a "down-side" is that JOBS are eliminated (maybe not when you consider the personnel needed to develop, install, and maintain the systems, as well as the "operators" working from shore…)

JPAR is on to something per pirates as a crew-less ship is a tempting target. Robo Pirates perhaps too? And without a crew, Salvage Rights will have to be re-written. Without a crew, what does one do if there is a malfunction, a mechanical breakdown? My Wife has crewed on a big Natural Gas transport, and there were lots of things to do, to keep tabs on, to adjust...
And yes, what about sails? You want to save on fuel oil, this would help.
I guess the folks at Rolls Royce can make a promise like in the film WESTWORLD, "Where nothing can go wrong. "

If they were made submarine, it eliminates or potentially eliminates many of the negatives. Just run 10 feet under, dive a little to get under other ships. It would be very difficult for pirates to do anything. Hard for them to even find it. It would not be like a military submarine that has to be able to go several hundred feet down. This would be maximum 150 feet. Perhaps even less. You can ignore the weather, most ocean traffic. Big retractable air scoop/exhaust port. Hold and compress enough air for 30 minutes operation or have a hybrid drive and some batteries for anytime it has to go lower than the air scoop.

Obviously whoever wrote this doesn't have a clue. Crews are mostly 3rd world so costs are minor, not 44 percent, likely well under 10 percent.
The whole crew could be put in one 30x40' cabin on the deck, just not that costly.
What will be costly is the first time it breaks down and they have to pay for a service call to the middle of the ocean.
And biggest problem, pirates. These ships will be boarded, robbed or completely taken by the various criminal gangs, making it not cost effective.
Then again the crew members steal so much shipping cars, etc you have to take the stereo, etc out as they will rip the dash apart causing $1,000's of damages on most every personal imported car I use to do the DOT/EPA on to make them US legal.

Great, we can automat everything, and nobody will need to work, but because no one will have no money there will be no one to buy the goods. A unfeedback loop.

This is all about as funny as Amazon and their delivery drones. Running underwater would take a great deal more power. Simply put, there is no way to run a ship without a crew. I'd like to see a helmsman try to keep his boat turned into the wavesin a storm, especially with the ify satellite coms you expect during a big blow. Also, you certainly couldn't remote pilot one into a harbor. Can you imagine unmanned ships sailing under the Golden Gate bridge headed for Oakland?