[electricships]

What is the state-of-the-art for battery-electric ships?

the power is probably MVDC from the large battery. And these are large xxMW motors.

So will we end up usong inverters anyway?

[midoridensha]

No modern high-performance motor that needs speed control uses electric power directly from a battery or the mains: it always goes through an electronic controller of some kind, which uses transistors to generate the necessary waveforms at the required voltage. Whether the motor itself is a permanent magnet motor or an inductance motor doesn't really matter; they each have strengths and weaknesses, but they both need electronic controllers.