The impact of America’s navy into the war had a sudden and prodigious effect. The effective cooperation between Britain and American navy staff delivered new and improved tactics and strategy. The most important of these was the convoy system. The allies had not adapted a convey system to protect their supply boats. Morison believed that “Sims found to his surprise, that the allies had not yet adopted the convey system… to be protected from submarines”. The American’s instigated this system and it brought great results and enabled American troops to safely cross. After great success the US Navy also planned and executed a mine barrage across the North Sea, which blocked the exit to enemy submarines. Without the American navy it is probable that the allies would have been defeated before their ground troops even arrived.
The American entry into the war had an enormous impact on morale. As American troops flooded in through Paris, the allies were joyous and finally believed that the war would now be won. As R. Holmes believed “The Americans were like a transfusion of blood arriving to reanimate the pallid body of France”. Conversely, on the German side the soldiers now had to face the richest nation in the world, which would be able to send unlimited numbers of fresh men into the war. They were now battle worn and did not believe that they could win, only hoping they could