Now in this densely packed shipping area, which extended from the north of Ireland to Brest, there were seldom more than eight or ten submarines engaged in their peculiar form of warfare at one time. The largest number which I had any record of was fifteen; and this was an exceptional force; the usual number was four, six, eight, or perhaps ten. Yet the men upon our merchant convoys and troopships saw submarines scattered all over the sea. We estimated that the convoys and troopships reported that they had sighted about 300 submarines for every submarine which was actually in the field. Yet we knew that for every hundred submarines which the Germans possessed they could keep only ten or a dozen at work in the open sea. The rest were on their way to the hunting grounds, or returning, or they were in port being refitted and taking on supplies. Could Germany have kept fifty submarines constantly at work on the great shipping routes in the winter and spring of 1917--before we had learned how to handle the situation--nothing could have prevented her from winning the war. Instead of sinking 850,000 tons in a single month, she would have sunk 2,000,000 or 3,000,000 tons. The fact is that Germany, with all her microscopic preparations for war, neglected to provide herself with the one instrumentality with which she might have won it. This circumstance, that so few submarines could accomplish such destructive results, shows how formidable was the problem which confronted us. Germany could do this, of course, because the restricted field in which she was able to operate was so constantly and so densely infested with valuable shipping.