Tanker design reflected industrial bottlenecks

The Dale class used commercial machinery rather than the turbines and Admiralty boilers needed by fast warships and fast oilers. Slower replenishment ships could carry more fuel and enlarge the support fleet without competing directly with destroyer and cruiser construction. The intended sequence was to expand general tanker capacity first and use later growth in high-performance machinery production for specialized fleet support. An oiler could burn fuel from its own cargo if necessary, though doing so reduced the load available to deliver and was therefore avoided when possible. Logistics planning was constrained by the same engines, boilers, yards, skilled labour, and usable cargo as combat construction.