But the Germans made no concerted campaign against our transports; fundamental conditions, already described, rendered such an offensive hopeless; and the skill with which our transport service was organized and conducted likewise dissuaded them. I have always believed that the German Admiralty ordered their U-boat captains to let the American transports alone; or at least not to attack except under very favourable circumstances, and this belief is rather confirmed by a passage in General Ludendorff's memoirs. "From our previous experience of the submarine war," General Ludendorff writes, "I expected strong forces of Americans to come, but the rapidity with which they actually did arrive proved surprising. General von Cramon, the German military representative at the Austro-Hungarian Headquarters, often called me up and asked me to insist on the sinking of American troopships; public opinion in Austria-Hungary demanded it. Admiral von Holtzendorff could only reply that everything was being done to reduce enemy tonnage and to sink troopships. It was not possible to direct the submarines against troopships exclusively. They could approach the coasts of Europe anywhere between the north of England and Gibraltar, a front of some fourteen hundred nautical miles. It was impossible effectively to close this area by means of submarines. One could have concentrated them only on certain routes; but whether the troopships would choose the same routes at the same time was the question. As soon as the enemy heard of submarines anywhere he could always send the ships new orders by wireless and unload at another port. It was, therefore, not certain that by this method we should meet with a sufficient number of troopships. The destruction of the enemy's freight tonnage would then have been undertaken only spasmodically, and would have been set back in an undesirable manner; and in that way the submarine war would have become diverted from its original object. The submarine war against commerce was therefore continued with all the vigour possible." Apparently it became the policy of the German Admiralty, as I have said, to concentrate their U-boats on merchant shipping and leave the American troopships practically alone--at least those bound to Europe. Unfortunately, however, at no time did we have enough destroyers to provide escorts for all of these transports as fast as they were unloaded and ready to return to America, but as time in the "turn around" was the all-important consideration in getting the troops over, the transports were sent back through the submarine zone under the escort of armed yachts, and occasionally not escorted at all. Under these conditions the transports could be attacked with much less risk, as was shown by the fact that five were torpedoed, though of these happily only three were sunk. III