Caleb James DeLisle (nprofile…mj4q) FourOh-LLC (nprofile…08ze) the only way you can make a VLCC run on straight crude is to power it with steam turbines, since boilers can be happily fed used tires, cats and unruly Filipinos.
There are flex-fuel naval diesel engines which can also run on natural gas from what I've heard, but I left this field before seeing one with my own eyes.