How steam warships heated heavy fuel oil from cold

How did warships heat heavy fuel oil when the boilers were cold?

A diesel-powered heater warmed enough oil to start one boiler, whose steam then heated fuel for the rest of the plant.

Heavy fuel oil must be warmed before it will flow and burn properly. Ships normally kept one boiler ticking over so its steam could heat the fuel system. During a true cold start, diesel generators powered heating elements until enough oil was ready for the first boiler. Steam from that boiler then warmed more fuel and allowed the remaining boilers to come online in sequence.