You are right. I forgot to account for the fact combustion engines have a terrible thermal efficiency: about 20%, which gives the boat only 2 kWh per liter of d

You are right. I forgot to account for the fact combustion engines have a terrible thermal efficiency: about 20%, which gives the boat only 2 kWh per liter of diesel, meaning it was using 200 kWh daily, more in line with the electrical version.