So, just to add to the significance of the above. The High Seas Fleet by 1914 was going to fuel loads that were about 90% coal and 10% oil. The Konigs had 3 oil fired and 12 coal fired boilers. On the coal fired boilers, they'd spray the oil on the coals to increase the heat. If the German navy had been competent, one solution at the start of the war would have been to immediately take stock of the capital ships existing and the building programme and decide which ships to complete as warships, and which to convert to merchantment or tankers. This would take advantage of hulls that sat uselessly in port while Germany lost the war. In August 1914, a reasonable breakout of resources might be -
Derfflinger, Lutzow - complete as warship.
Bayern - complete as warship
Baden, Salamis, Hindenburg - complete as oilers or fast cargo ships.
Saschen, Wurttenberg, Mackensen Class - cancel, break up, and replace with new CL's or supply ships.
Predreadnoughts (Wittelsbach, Kaiser Friedrich) - convert to oilers or fast cargo.
The oilers would allow at-sea refuelling where oil was used for cruising and the coal was kept in reserve. Hipper's BC squadron (1916) of five ships, with an oiler, might consume 1,200 tons of fuel per day if not doing high-speed work. With 18,500 deadweight carrying capacity on a stripped-down Mackensen, that gives a working figure for the other ships if converted - 60% of tonnage could be used for tanking. One converted Kaiser Friedrich at 12,000 tons might therefore be about a 7,200 ton carrying capacity tanker capable of 16kt or 17kt, or 6 extra cruising days for Hipper's squadron, (1,700nm).