Naval Convoy

NAVAL CONVOY Naval convoy is a term used in naval warfare to describe the system of defending merchant ships, whereby the vessels sail in groups "convoyed" by warships. Until the 17th century the English term was to "waft" and a warship employed on this duty was called a "wafter." The practice of sailing in convoy was com mon in the middle ages, more especially because most ships, whether ostensibly warships or not, had some sort of armament, and they could thus afford each other some mutual protection.

The problem of mercantile convoy was fundamentally different in the World War from what it had been in the days of sailing ships. Merchant vessels in the 18th century made very few round voyages in the year, often only one. The length of each passage was uncertain, depending on wind and weather conditions, and the delays caused by assembly, awaiting escort and sailing in groups, were comparatively unimportant. The owners of fast sailing vessels might lose the profits to be gained by forestalling the market, but the nation suffered little. Hence trade could be carried on in time of war by a comparatively few convoys of great size. A homeward bound West Indian convoy might com prise 100 or 1 so vessels; there are records of Baltic convoys during the Napoleonic wars of over 50o sail. Since those days, the greater frequency and certainty of voyages under steam has per mitted the growth of massed industrial populations, depending for their very life, not merely on an immense volume of imported foodstuffs and raw materials, but on its arrival in a steady, con tinuous stream of cargoes. Throughout the World War the stocks of food, of munitions and of materials for civil industries were small in comparison with annual requirements, and had to be continually renewed. The holding back of supplies for a few months, or even for a few weeks, might entail irremediable dis aster. Thus, if trade were to be run in convoy at all, it must be ' in numerous small convoys run to a regular schedule, not in a few large convoys at irregular intervals. The contrast may be illus trated by the fact that, during the first two years of the War of the Austrian Succession, 35 outward and 45 homeward convoys sufficed for the requirements of the ocean trades ; in the summer of 1918, 4o outward and 42 homeward convoys were run in the ocean trades alone every 32 days. In these circumstances convoy called for a greater allocation of force and a 'far more elaborate organization than in the past. At the best, too, it entailed very serious delays to the faster ships, owing to the wide discrepancies in speed between steamers, even of similar type. Neither to the commercial nor to the naval mind was convoy a light matter.

Early Part of the World War.

During the first two and a half years of war, the use of convoy was restricted to the protec tion of troop movements. As the submarine campaign increased in intensity, escort was frequently given, within the danger zone, to tankers and vessels with important Government cargoes; but the introduction of organized mercantile convoy was delayed until 1917. So long as the attack on commerce was carried on by sur face warships, the total effect, despite the notoriety attained by the "Emden" and other raiders, was comparatively trifling, and even the submarine campaign, in its earlier stages, produced an astonishingly small effect on the flow of commerce. Towards the end of 1916, however, the losses of neutral as well as of British and Allied shipping, became very serious, and the outbreak of un restricted submarine warfare in Feb. 1917 compelled a recon sideration of the whole problem of trade protection. At this time the general run of opinion at the British Admiralty was strongly against convoy. It was condemned both as impracticable and undesirable; impracticable because there were not enough cruisers, destroyers and patrol craft to provide escorts for the trade, and because accurate station keeping would be impossible in a group of steamers of varied type and speed; undesirable because of the delays involved, and because any protection derived from escort would be outweighed by the disadvantage of offering a large target to torpedo attack.

Organized Convoys Begin.

The delays caused by the hold ing up of shipping and by deviation to avoid danger areas were now, in fact, so serious as to discount one of the chief objections to convoy, and the losses suffered during the first three months of unrestricted warfare (see SUBMARINE CAMPAIGNS) were so heavy as to threaten disastrous results to the supply system of the Allies. The existing methods of protection were clearly in adequate, and the advocates of convoy became insistent. In Feb. 1917 the French coal trade was organized in a system of con trolled sailings which rapidly developed into regular convoys, and in April a Scandinavian convoy was introduced to protect the helpless, unarmed n' itral, trading on Allied account, in the North sea. Meanwhile, the application of convoy to the ocean trades was being persistently urged both within and without the anti submarine division of the Admiralty. A special committee was appointed at the Admiralty during May to draw up a detailed scheme of convoys for the ocean trades, and during the same month two experimental convoys were sailed from Gibraltar and Hampton Roads respectively. Both these experimental convoys arrived without loss, and the experience gained went far to dis pose of the bogey of station keeping. Meanwhile, investigations had shown that the difficulty of providing escort had been mag nified by an exaggeration of the number of voyages to be pro tected, and the arrival of United States destroyers at Queenstown (Cobh) increased the available force. Regular convoys from Hampton Roads were started in June ; from Sydney (Cape Breton), New York and Gibraltar in July; in August the system was extended to the south Atlantic trades and the outward traffic.

The system adopted for convoys bound for England was for a group of steamers, collected at a port of assembly, to be escorted by a cruiser or armed merchant cruiser, giving protection against surface raiders, to a rendezvous outside the submarine danger zone, whence the convoy was brought in by a destroyer escort. Outward convoys, collected at assembly ports on the west and south coasts of England, were taken through the danger zone by a destroyer escort, to a point of dispersal outside the ordinary limits of submarine activity, whence the ships made their way individually to their ports of destination. In order to economize the forces used as destroyer escorts, which included destroyers, sloops and in some instances P-boats and trawlers, the escort, which had taken an outward convoy clear of the danger zone, was required to steam from the point of dispersal to the rendezvous with a homeward convoy, which it then brought in. The whole system thus depended on an exact synchronization Of the outward and homeward programmes, which threw an immense strain on the convoy section at the Admiralty, and on the commanders, officers and crews of the escorts themselves.

Work of the Convoys.

Convoys, including both Allied and neutral ships bound for or sailing from British or northern French ports, as well as those in the Mediterranean, were organized by the British Admiralty, and the bulk of the escorts were provided by the British Navy, although valuable assistance was given by United States cruisers and destroyers in the Atlantic and by Japanese destroyers in the Mediterranean. The French Navy also assisted in the ocean escort of a special convoy started during 1918 for American storeships to ports in the Bay of Biscay. The transport of United States troops to Europe was carried out in part by special troop convoys, organized and escorted by the United States Navy ; but in the spring of when the great German offensive made it necessary to speed up reinforcements, a large amount of British tonnage was allocated to the service, and special fast troop and cargo convoys were inaugurated from New York to Liverpool and from Halifax to Liverpool and London. Thanks mainly to these convoys, well over I,Ioo,000 United States troops were carried in British ships, with a total loss, from war and marine perils, of 637.

Success of the System.

From the first the convoys proved a triumphant success, and conclusively refuted the arguments against the system. The grouping of the ships diminished the number of targets offered to the attack, and since the convoys themselves followed carefully chosen and carefully varied routes, and could be deflected, by wireless, from areas of known sub marine activity, they proved as valuable in their power of evading attack, as in the actual protection provided by the escort. When located by a submarine, they proved far less vulnerable than the opponents of the system had supposed. The threat of instant retaliation by the escort, and the menace presented to a sub marine by a group of ships manoeuvring in concert on a broad front, hampered the movements of the assailant, and even when the attack was successful, there was no such wholesale havoc as had been 'feared.

In the North sea there were two serious disasters, both due to attacks by surface vessels ; but in the ocean trades, even when a successful attack was made on a large convoy, it was rarely that the submarine claimed more than one, or at most two victims. The total percentage of loss was as follows : Ships escorted safely in ocean convoy 16,539 99.08% Torpedoed in convoy 102 Lost by marine peril . . . . 16 0.09% Lost after parting company, etc. . 36 0.22% Total railings . 16,693 100•0o% In the short sea convoys (Scandinavian, Dutch, British east coast, French coal trade and Mediterranean local) there were over 8o,000 sailings, with a loss of less than o•5%.

At the outset, the advantages of convoy, more particularly in the north Atlantic, were partly neutralized by the additional de lays due to steaming to the port of assembly, awaiting the sail ing date and adjusting speed to that of the slowest ship in the group. These delays, however, were greatly reduced, during 1918, by a more careful grouping of the ships, and by co-operation be tween the Admiralty, the Ministry of Shipping and the shipowners themselves. Convoy committees of shipowners at Liverpool, New York and London did yeoman service in the adjustment of sailings to the escort programmes, and the fast troop convoys, in particular, ran with almost the regularity of a railway time table. In station-keeping and manoeuvring also there was im provement, and in later convoys there were few stragglers. (See also BLOCKADE and SUBMARINE CAMPAIGN.) BIBLIOGRAPHY.-C. E. Fayle "Seaborne Trade," History of the Bibliography.-C. E. Fayle "Seaborne Trade," History of the Great War, Vol. 3 (1924) ; Earl Jellicoe The Crisis of the Naval War (1920) ; Admiral W. S. Sims The Victory at Sea (1920) ; Sir J. A. Salter Allied Shipping Control (1921) .