Submarine Warfare of To-Day

single troopship.5 The first Canadian army of 33,000 men crossed the Atlantic in one big fleet of forty liners, under the escort of four cruisers and a battleship, in October, 1914, without accident. Transports to the number of 60 were required to convey the first Australian army over the 14,000 miles of sea to Europe, and it was while convoying this huge fleet that the cruiser Sydney chased and destroyed the German raider Emden. The Russian force which rendered valuable service in France was safely convoyed over the 9000 miles of sea from Dalny to Marseilles. Never once during the four and a half years of war was the supply of food, munitions and reinforcements, or the return of the wounded—to and from the many theatres of land operations—seriously hindered by the German, Austrian or Turkish navies.

Turning to the gigantic task of guarding England’s food supply, we find, in one notable case, an example of the good work performed almost daily for nearly five years. Over 4500 merchant ships had been escorted across the North Sea to Scandinavian ports alone before the disaster of 14th October 1917 befell the convoy on that route. On that occasion the anti-submarine escort of three destroyers were intercepted, midway between the Shetland Islands and Norway, by two heavily armed German cruisers. The destroyers fought to the last to save their charges, but unfortunately only three merchant ships succeeded in getting safely away. Five Norwegian ships, three Swedish and one Danish ship were sunk. From this it will be observed that not only British merchantmen were protected by escorts.

The second attack on the Scandinavian convoy occurred on 12th December. The escort consisted of two destroyers, the Partridge and Pellew, with four armed trawlers. Fortunately the convoy was comparatively a small one, for it was attacked and almost totally destroyed in the North Sea by four of the largest German destroyers. H.M.S. Pellew, although badly damaged, succeeded in returning to England.

It may be rightly thought that in both these cases the escorting flotilla was not strong enough, but it should be remembered that if heavier ships had been employed they would have been much less able to cope with a submarine attack. The escort in both cases was purely an anti-submarine defence, and only on the Scandinavian and Netherlands routes was a surface attack at all possible, because all exits from the North Sea were securely closed by the strategic positions occupied by the Grand Fleet and the battle cruiser squadrons, in conjunction with subsidiary fleets at Harwich and extensive mine-fields.

When it became apparent that surface as well as submarine attacks on the North Sea convoys had to be provided against, other means were promptly adopted, and no further disasters occurred.

The strong escort accompanying the transports bringing to Europe the first American army were attacked at night by a submarine, but succeeded in avoiding the torpedoes fired. This was due to the smartness with which the United States warships were man?uvred. Three subsequent attacks on the same convoy route also failed.

The Report of the War Cabinet for the year 1917 gives some remarkable figures in support of the convoy system. On the Atlantic routes about 90 per cent. of the ships were formed into fleets and escorted. From the inauguration of this system the loss on these routes from all causes was 0^.82 per cent., and if all the trade routes to and from the United Kingdom are included, the loss was only 0^.58 per cent. With these figures in mind, who will deny that the navy is the surest form of national as well as Imperial insurance?

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.

^{Fig. 20.—Diagram showing division of sea into anti-submarine patrol areas.}

Each square of sea was covered once or twice daily by its own patrol ship or flotilla. Where the danger was less the patrol was not so frequent and the squares were almost indefinite in size, but where the chances of successful operations were exceptional, as in the Straits of Dover, additional offensive measures were employed (see under Mine Barrages).

This, then, was the chess-board on which the game of submarine warfare was played. To facilitate communication between the different patrols spread over the squares of sea, wireless was fitted in many ships, and war signal stations were erected on prominent points of land. Each base was able to communicate by wireless with any of its ships out on patrol duty, and was also connected by land-line telegraph, telephone and wireless with naval centres.

These latter were head intelligence offices, usually situated at the great bases of the battle fleets. In this way any concentration of hostile surface warships noticed by the patrols (sometimes submarines were employed, especially in the Heligoland Bight) could be communicated in a few minutes to the admirals commanding the Grand Fleet, the Battle Cruiser Squadron or other large fighting organisations.

At the naval centres the movements of hostile submarines were recorded on charts. If, for example, it was reported from a patrol boat that the U16 had torpedoed a ship in square “C,” area 41, at 10 a.m. (G.M.T.6) on 4th August, and the patrol had arrived on the scene too late to be of any service, a warning could be wirelessed to hundreds of vessels on the seas surrounding the scene of outrage to keep a careful look-out for the U16.

^{Fig. 21.—Diagram showing how an area is covered by patrols. A. Unit or flotilla of ships may proceed out from the base on course indicated by arrows B, which would be called the “Northern Inner Beat,” and return to harbour on course A, “Northern Outer Beat.” Other units of ships would simultaneously follow the course E. These and}