Maybelle Diggory:
Coconut oil? Good heavens. The ship would smell like an island if Mr Hawkesbury bought any of that stuff.
Actually ... if you're
interested ...
Rudolf Diesel's original engine was designed to operate on petroleum (specifically crude oil). But initial tests with his prototype proved petroleum to be
too viscous, so it was soon replaced with regular petrol and kerosene for further testing purposes.
During early diesel engine development, fuels such as petrol, kerosene, gas oil, vegetable oil and mineral oil, as well as mixtures of these fuels, were used.
Eventually, the fuels specifically intended to be used for diesel engines were typically petroleum distillates and coal-tar distillates due to their higher "lower heating value" [LHV] -- aka
net calorific value [NCV] or
lower calorific value [LCV] -- all of which are measures of available thermal energy produced by combustion of a fuel. Petroleum and Coal Tar distillates provide more energy from less fuel.
Vegetable and other Bio-Sourced fuel oils tend to burn "cleaner" -- but
still produce
some "bad" emissions -- and are, of course, more "sustainable".
A truly
global diesel engine fuel standardization didn't happen until
after WW2 -- and the
modern European diesel fuel standard was established in 1993.