CHAPTER X
THE MYSTERIES OF SUBMARINE HUNTING EXPLAINED
When all is said and done, anti-submarine warfare is very like big-game hunting. Success depends entirely on the initiative, skill and resource of the individual hunter. Contrary to general belief, there is, at present, no sovereign remedy for the depredations of under-water craft with their torpedoes and mines. There are, however, several recognised methods of attack and defence employed by surface ships in this newest form of naval warfare.
When the new navy took the seas in 1914-1915, bases were established not only round the coasts of the British Isles, but also in the more distant seas. The principal danger zones were, however, the North Sea, the English Channel, the Irish Sea, the Mediterranean and the eastern portion of the North Atlantic. It was through these waters that every hostile submarine must pass on its voyage out and home.
This geographical factor restricted the theatre of major operations to some 180,000 square miles of sea. Minor offensive measures might have to be adopted against individual U-boats cruising at long distances from their bases, as actually occurred off the United States coast, but the fact of Germany possessing large submarine bases only along her own North Sea coast, and temporary ones on the Flanders littoral, enabled a concentration of Allied anti-submarine craft to be made in the narrow seas which afforded the only means of entry and exit to and from those bases.
The same may be said of Austria in the Adriatic and of Turkey behind the Dardanelles.
This favourable combination of circumstances would not occur if (however unthinkable) England, France or the United States were ever to wage a rigorous war against shipping. The large number of oversea naval bases possessed by these Powers would cause every sea to become a danger zone within a few hours of the commencement of hostilities. No effective concentration of hostile surface craft would be possible with the zone of operations spread over the water surface of the entire globe, and if the bases themselves were secured by predominant battle fleets, or numbers of heavily armed monitors, the seas would quickly become impossible for purposes of hostile transport.
This geographical restriction of the German and Austrian danger zones made effective concentration of the Allied anti-submarine fleets and their devices possible. The 180,000 square miles of sea, forming the theatre of major operations, was, on special charts, divided into areas, comprising a few hundred square miles of sea. Each area was given a distinctive number, and a base was established for its own patrol and minesweeping fleet.
The areas themselves were again subdivided on special charts into squares or sections. Each square covered a few leagues of sea and was known by an alphabetical sign. In this way the waters of the submarine danger zone were divided into areas, with their bases and protective fleets, and squares with their respective squadrons or ships.
