As the historian Jonathan Parshall has calculated, that level of effort would have taken half of the Imperial Navy’s monthly allotment of fuel. Measured in terms of tonnage delivered per unit of oil burned, cargo ships were thirty times as efficient as destroyer-transports. But use of the slow ships was fruitless as long as U.S. pilots controlled the skies of the Slot. It was a difficult problem: Without the heavier capacity of those larger vessels, Imperial ground forces would be unlikely to take the airfield.
