But more and more submarines were launched, and they still sneaked out to sea along the Dutch and Norwegian coasts where the Navy could not stop them because they used to slink through "territorial waters," that is, within three miles of the coast, where the sea belonged to the nearest country, just the same as the land. The Navy, however, had lines of patrols always on the watch from the Orkneys to the Shetlands, on to Iceland, over to Norway, and north to the Arctic ice. The narrow waters of the English Channel were watched by the famous Dover Patrol under Sir Roger Keyes. From Folkestone to Cap Griz Nez in France there was an unbroken line of the strongest searchlights on vessels anchored to ride out the biggest gales. Seven miles west was another line. Between were hundreds of patrol boats always ready, night or day, to fire at anything on the surface or to drop depth charges on anything that dived. A depth charge is a sort of mine that can be set to go off at a certain depth, say thirty to sixty feet down, when it makes a sea-quake that knocks the submarine out of gear and sinks it, even if it does not actually hit it. Besides all these guards on the surface there were nets and mines underneath. That is why the British army in France never had its line of communication with England cut for one single day all through the war. Now and then the Germans tried a destroyer raid from their ports on the Belgian coast, or even from their own coast; for they would sneak through Dutch waters within the three-mile limit as well as through the Danish or Norwegian. They played a game of tip-and-run, their gunners firing at any surface craft they saw (for they knew no Germans could be anywhere but underneath) and their captains streaking back home at the first sign of the British Navy. On the night of the 20th of April, 1917, they were racing back, after sinking some small craft, when an avenging flotilla of British destroyers began to overhaul them. Seeing that one of the Germans might escape in the dark, the _Broke_ (named after Captain Broke of the _Shannon_ in the War of 1812) turned and rammed her amidships. The Germans fought well, swarming aboard the _Broke_ and fighting hand to hand, as in the days of boarding. But Midshipman Giles stood up to the first of them, who was soon killed by a bluejacket's cutlass; and then, after a tremendous tussle with swords and pistols and anything else that was handy, every German was either driven overboard or killed on the spot, except two that surrendered.