"Paul M. Eldridge" wrote in message

As I recall, Bunker C is also considerably heavier than regular diesel
fuel. Even at only modest temperatures, it has to be preheated to
get it to flow.

I've never laid eyes on the stuff myself, but its been described to me
as the scrapings from the bottom of the barrel.... with a viscosity
not unlike that of asphalt. ;-)

Cheers,
Paul

We used to burn it where I worked years ago. It had to be delivered hot
(IIRC, about 125) in order to drain from the tanker truck. We'd start the
boilers on #2 oil and a steam probe from the boiler into an intermediate
tank heated it to a pumpable oil. Another pump circulated that back into
the 10,000 gallon #6 tank to keep it warm. More difficult to burn, it was
much cheaper to buy and has a higher Btu per gallon compared to #2.