at all times with the longitude and latitude of their ships; their instructions required them immediately to send out
this information whenever they sighted a submarine or were attacked by one. In these several ways we had
little difficulty in "shadowing" the U-boats. For example, we would hear that the U-53 was talking just out-
side of Heligoland; this submarine would be immediately plotted on the chart. As the submarine made only about ten knots on the surface, in order to save fuel oil, and much less under the surface, we could draw a circle around this point, and rest assured that the boat must be somewhere within this circle at a given time. But in a few hours or a day we would hear from this same boat again; perhaps it was using its wireless or attacking a merchantman; or perhaps one of our vessels had spotted it on the surface. The news of this new location would justify the convoy officers in moving this submarine on our chart to
this new position. Within a short time the convoy officers acquired an astonishingly intimate knowledge of these
boats and the habits of their commanders. Indeed, the personalities of some of these German officers ultimately
took shape with surprising clearness ; for they betrayed their presence in the ocean by characteristics that often
furnished a means of identifying them. Each submarine behaved in a different way from the others, the difference,
of course, representing the human element in control.
One would deliver his attacks in rapid succession, boldly and almost recklessly; another would approach his task with the utmost caution; certain ones would display the meanest traits in human nature; while others—let us be just—were capable of a certain display of generosity, and possibly even of chivalry. By studying the individual traits of each commander we could often tell just which one was operating at a given time; and this information was extremely valuable in the game in which we were engaged.
"Old Hans is out again," the officers in the convoy room would remark.
They were speaking of Hans Rose, the commander of the U-53; this was that same submarine officer who, in the fall of 1916, brought that boat to Newport, Rhode Island, and torpedoed five or six ships off Nantucket. Our men never saw Hans Rose face to face; they had
