'Operations in the Pacific are largely guided by the information we obtain of japanese deployments. We know their strength in various garrisons, the rations and other stores continually available to them, and, what is of vast importance, we check their fleet movements and the movements of their convoys. The heavy losses reported from time to time which they sustain by reason of our submarine action, largely result from the fact that we know the sailing dates and routes of their convoys and can notify our submarines to lie in wait at the proper points.' 1