These raids spoilt German chances from the nearest ports to Britain. But they did not stop the submarine campaign; and there was still plenty of work for camouflage, convoys, and "Q" ships.
Camouflage at sea is a very different thing from camouflage on land. On land camouflage is meant to make one thing look like something else or to hide it altogether. But no kind of camouflage will hide a ship. Nor is there any point in making a boat look like anything else; for everybody knows that ships are the only things at sea. Camouflage afloat was therefore meant to confuse the submarine commander's aim by deceiving his eye as to his target's speed and course. By painting cunning arrangements of stripes and splashes of different colours a ship's course and speed could be so disguised that the torpedoist was puzzled in getting his sights on her and in working out the range and speed. If an old-fashioned sailor could have suddenly been dropped on to the deck of a transport in the midst of a convoy of camouflaged ships he would have thought all their helmsmen were drunk or stark, staring mad; for they would have seemed to be steering every which way at large and not one on any proper course at all.
When this was added to their other troubles the submarines thought twice before risking an attack on a convoy of ships guarded by cruisers, as well as by destroyers ahead and on both sides, zig-zagging about on the hunt for submarines, much as a good sporting dog quarters likely ground for game. A "mothering" cruiser would keep station astern, where she could have her weather eye on every one. In narrow waters like the English Channel there would also be an airship overhead, a little in advance, with seaplanes on the flanks. These aircraft could spot a submarine almost a hundred feet down in fair weather, just as seabirds spot fish. If a submarine did show up, it was kept in sight till the destroyers charged near enough to ram, shell, or torpedo it on the surface, or sea-quake it to death with a depth bomb if submerged. Three hundred and seven ships brought wheat from different parts of America to Britain, France, and Italy under special convoy in the summer of 1918, and only one was lost.