When the two fleets met for the first and only time in the Battle of Jutland off the Danish coast in late May 1916, the results were inconclusive. Battleship fought battleship only for a few hours at the close of the day. A cautious Admiral Sir John Jellicoe, acutely aware of the need to preserve Britain's existing naval superiority, rejected risky aggressive tactics. He was willing to forgo the possibility of destroying much of the German fleet in order to avoid the danger of heavy losses to the Royal Navy. Britain's command of the seas, as he interpreted it, meant reluctantly accepting an inconclusive action on the high seas. In the aftermath of Jutland, the German navy turned its hopes away from its surface fleet. Within six months, the advocates of an unlimited submarine offensive won the day. It began promisingly in the first months of 1917 as German U-boats attacked all merchant commerce going to and from the British Isles. The crisis in the entire naval conflict now emerged: it was the war between the submarine and the weapons that could be employed against it. If the submarines won, the Allies faced the loss of their command over the sea lanes. For Britain, this meant starvation, a situation that pointed toward Germany's ultimate victory in World War I. Although the U-boats found numerous targets down to the closing weeks of the war. Allied countermeasures, notably the use of the convoy, tipped the balance in the undersea war before the last months of 1917. Thus, both acts in the naval drama had the same result. In the first act, the surface war from 19f4 through 1916, command of the sea remained unassailably in Allied hands. The second act, the undersea war of 1917 and 1918, raised the possibility of Germany's naval superiority. In the end, although after many worrisome months, the Allies prevailed here as well.