I am not naysaying electrical propulsion, or I think disputing anything you have said.

The numbers Crouch's formula produce are relatively close to the numbers you have produced. And I have verified them a number of times on different hull forms, true they are for a planing hull, but the Proa is almost a planing hull, better actually.

About efficiency though, the generator may be 90% efficient and the batteries may be 90% efficient (I have 800 amp hours of LiPo batteries on my boat by the way, I have thought about cooking breakfast on them occasionally) but you are still dealing with DC power and the attendant line losses, bearings and shafts and controllers etc. And did I mention the diesel motor itself isn't that efficient? Every extra step in the process adds 'friction'.

Using a diesel engine to drive the boat through a generator, controller, and electrical motor is never going to be as efficient as using the the diesel motor driving the boat through a shaft.

But I agree with you, there are some big advantages to electrical propulsion. primarily the reduction in drag while sailing, less total weight (especially in fuel), hybrid systems are proven tech, the boats electrical needs get taken care of by default, prop regeneration and better fuel economy. Electricity doesn't need to be oversold.

The only 'downside' is that the boat doesn't have the power or mass to bash against a big storm or travel long distances against the wind and waves. In my mind those aren't really negatives though, schedules break boats and kill people.

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