Mystery-ships, fully armed, but having the appearance of an innocent coasting vessel, traversed the adjacent seas, but the most successful protection afforded to our transports and to our commerce was the adoption of the old system of "convoys." Convoys were seldom very successfully attacked, and ships lost while being convoyed did not exceed 3 per cent. The convoy system required very careful organisation. Ships have different speeds and different destinations, so we had convoys for ships of varying swiftness. We had not sufficient war ships or destroyers to act as convoys from shore to shore in the Atlantic, therefore the convoys crossing the ocean were only under the protection of a ship of war, and only met their escort fleet of destroyers when they reached the danger zone. At a given point the convoy broke up, some ships going up the St. George's Channel to Liverpool, the others proceeding to London and the Channel ports. The convoy system in the later stages of the war became very perfect, and although some enemy submarines boldly penetrated the protecting line of destroyers, and sank a few ships, they seldom got away again, and the knowledge of this had a very wholesome and a very deterrent effect. The valuable services performed by both English and American destroyers to our Mercantile Marine deserves the highest praise. The appearance of the River Mersey upon the arrival of a convoy was something to be remembered. Sometimes a convoy would consist of twenty or thirty large merchantmen, all dazzle-painted, stretching out in a long line from New Brighton to the Sloyne, while their escort of British and American destroyers made their rendezvous at the Birkenhead floating stage. Admiral Scheer, in his book, allows that the Germans lost half of their submarines, a considerable number he says were always under repair, and the difficulty of obtaining crews was an increasing one. Therefore, we think that it can be claimed that our navy had already mastered the U boat menace when the war ended.