Though their engines are among the most efficient on the planet, ships waste 50-70% of their energy as heat, although waste heat recovery devices can save a small percentage of the energy loss.
Electrical systems, on the other hand, are far more efficient. Electric cars may have had their problems storing energy, but once they come to use it, 90% goes to the wheels; the same is true of heat pumps and electric stoves.
There may be scant prospect of building enough wind turbines and solar panels to replace all of the fossil fuels on Earth; but it will not be necessary to do so, because running all of the same processes on electrical energy would