Proberly not, as the more heavy fuel also carry acids and sulfur there
simply are more dirt in the heavy fuels, something that is no problem
in a huge ships engine undertaking maintaince on regular times ,where
the pistons are houled and the rings cleaned every 2 month and, you
easily end up with an engine blocked by unburned remains, valves that
will not close well, all in all , what you think you save can add extra
costs while the engine suffer. ---- beside when the engine are not made
for the fuel the smoke can turn out to be a major problem.
Also even the old slow running engines are made for a particular fuel,
the jets in the carburator aswell as the spray holes in the diesel
engine, are made so that a wrong fuel will only caurse trouble , the
engine will turn out being very "dirty" and esp. more modern engines
will soon fail or the engine will soon be vorn out.