A time-shifted battleship still depends on its industrial base

How would HMS King George V refuel if 1913 Britain and the ship were sent into the Roman era?

The ship would still have access to Welsh coal because the counterfactual includes Britain's 1913 industrial and transport infrastructure.

The counterfactual moves the infrastructure of 1913 Britain as well as HMS King George V. Welsh coal production and the supporting transport system would therefore remain available in Roman times. The ship's endurance still depends on mines, handling facilities, and a supply network that keeps its machinery fueled.