Energy density of batteries is much lower than that of fossil fuels. Which means that the weight of the ships would increase. In addition to the high price of the batteries, potential risks of electrocution, etc.
There are intermediate options. Moving away from diesel towards natural gas would dramatically reduce emissions (including sulfur emissions), while retaining high energy density.
There are intermediate options. Moving away from diesel towards natural gas would dramatically reduce emissions (including sulfur emissions), while retaining high energy density.