Re: you mean
Isn't this going to always be a major problem with any attempt to build in autonomy in a 'ship' at all reliant on ICE technology - mechanically there are just too many points of failure?
A purely electrical system may also be highly complex, but is mechanically relatively simple: an electric motor attached to a drive shaft and propeller - essentially a single moving part. Yeah, if it breaks you're stuffed, but the odds of it breaking are very manageable.
Yes, lubrication has to be taken into account, but again, on such a simple mechanical system, is relatively manageable.
In contrast an ICE system can have literally hundreds of points of potential mechanical failure, many of them relatively trivial for an on the spot human to fix, but fatal to the autonomous functioning of the machine.