R-class coal and boiler choices

Did oil-supply fears justify a coal-powered 15-inch battleship like the R class?

Coal power was defensible, but the ships still could have used small-tube boilers and a more future-proof design.

Coal firing was separate from the real design issue: the ships could have remained coal powered while still using more forward-looking small-tube boilers. Coal was a defensible hedge against uncertain wartime oil supplies in 1914, so the Admiralty had reason to consider fuel security. The R class paired that caution with older boiler technology and a design that offered too little future margin. A conservative fuel choice could have been combined with a more advanced and adaptable battleship.