90 DEVELOPMENT OF THE THREE-PLANE NAVY 



of the convoy system to this list of the means adopted to combat the German submarine and 

 to reduce the sinkings of merchant vessels. This system was started experimentally in May, 

 1917, and was in complete operation three to four months later. Its adoption was made pos- 

 sible by the addition of American naval vessels, particularly destroyers, to the naval forces 

 of the Allies. The convoy system permitted the successful transportation of supplies and 

 troops from the United States to Europe; it was also a direct attack against German sub- 

 marines inasmuch as it forced them to attack merchant vessels in the presence of protecting 

 destroyers or other craft, and consequently to run the risk of a fight and of being sunk 

 themselves. By use of the convoy system and information as to the whereabouts of the Ger- 

 man submarines at sea, it was often possible to route convoys around these submarines in 

 safety. Comparatively few vessels, when in convoy, were sunk by submarines. 



In the preceding paragraphs are listed, as briefly as possible, the vessels and means 

 employed against the German submarines and which were finally successful in the anti-sub- 

 marine campaign. It is evident that the German unrestricted submarine warfare was diffi- 

 cult and expensive to combat. It required much time to develop and to put into operation 

 means of defeating this method of attack. In spite of the fact that the British Grand Fleet, 

 to which, in the latter part of the war, were added some American naval vessels, held the con- 

 trol of the surface of the sea by keeping German surface naval vessels in German harbors, 

 the control of the waters imder the surface of the sea was but slowly taken away from 

 the German submarines. 



The different uses made of the submarine by the Germans and by the Allies in this war 

 demonstrated that it has many uses which previously had not been considered possible. It 

 was found that submarines could remain at sea for long periods, on extended cruises of 

 thousands of miles, without the assistance of mother ships or tenders ; that submarines could 

 fight with torpedoes against other submarines; that a submarine armed with 4 or 6-inch 

 guns, especially under favorable conditions of light, could shell surface vessels with little 

 danger to itself owing to the small target it presented, combined with the fact that, while 

 the surface vessels were easily seen by the submarine, the low-lying submarine was practi- 

 cally invisible to the surface vessels. The submarine can do effective patrolling or scouting 

 in the immediate vicinity of the ports of the enemy, while submerged, which no other type 

 of craft can do. 



The extensive and effective use of submarine mine layers at long distances from their 

 bases was quite unexpected. Submarines made long submerged nms, through mine fields 

 and other obstructions, which previous to this war had been considered impossible. For 

 example, we may refer to work of this kind done by British submarines in the Dardanelles 

 as well as to that done by German submarines. The use by the latter of artillery of increas- 

 ing caliber up to 6 inches and the adoption of 12-inch guns in the case of British submarines 

 are developments of the World War. 



The torpedo equipment of submarines today is far behind its possibilities of develop- 

 ment. The torpedoes supplied to submarines are of shorter range than those supplied to sur- 

 face vessels, in consequence of the incorrect assumption that submarines will always fight at 

 short range. Large submarines can and should be provided with especially large, long-range 

 torpedoes carrying explosive charges up to 1,000 pounds or more and thereby increase 

 their power of attack, particularly against large naval vessels, even when escorted by a pro- 

 tecting screen of small, fast vessels. Although the great advantage of transverse torpedo 

 tubes in facilitating attacks, as compared with bow tubes in combination with the practi- 

 cally useless stem tubes, is generally realized, yet little has been done to develop the trans- 



