There already exist purpose-built chargers for electric ships. See, for example, https://www.stemmann.com/en/products/charging_systems/ferryc...

To support a 48 hour recharge of the battery hypothesized upthread, you would only need to scale up this system by about 10x. Or attach 10 along the length of the ship. Or some combination of those options.

This is a non-problem.

Edit: Excuse me, but I misread the brochure. The existing system need be only scaled up by a factor of 2.5x to recharge a container ship in 48 hours.