Barring internal labor politics, infrastructure immediately near docks and rail shouldn't be an issue to upgrade as the sheer scale of modern cargo vehicles mea

Barring internal labor politics, infrastructure immediately near docks and rail shouldn't be an issue to upgrade as the sheer scale of modern cargo vehicles means you could get all the resources for such in a single load. Also I believe most ships are "hybrids" anyway, in that their props are driven by motors directly connected to generators on their engines, since when you are dealing with engines that are literally two stories tall creating a matching gearbox becomes quite difficult. As such the biggest pain point will be battery capacity, but if we are willing to forgo the logistical difficulties of super-massive ships can be brute-forced with lower quality batteries in even more massive ships.