Excellent in theory but very difficult of accomplishment in actual practice. The diagram given will explain the details of this elaborate contrivance, which, however, was soon discarded for more practical methods, although at least one German submarine is known to have been destroyed by it.

These little engines of destruction were intended for fighting at close quarters, and can be described here in a few lines because of their guileless simplicity. They consisted of conical explosive bombs on the ends of broom handles! A strong man could whirl one of them round his head, like a two-handed sword or battle-axe, and, when the momentum was sufficient, hurl it over the water for about seventy-five feet. On nose-diving into the sea and hitting the hull of a submarine in the act of rising or plunging, the little bomb, containing about 7 lb. of amatol, was exploded by contact.

The damage inflicted on one of the earlier types of submarines by an under-water hand-grenade or lance bomb depended entirely upon what part of the vessel happened to be struck. Their sphere of usefulness was, from the first, very limited, and the advent of the big cruiser submarine, with armoured conning-tower and 5-inch guns, rendered them obsolete.

We now come to a more useful device of the purely defensive type employed to screen surface ships from submarine attack. The very simple mechanical and chemical apparatus needed for making the heavy clouds of smoke needs no description beyond that given in the text, but something must be said here regarding the methods of use.

It was not until the third year of the Great War had been ushered in by the unprecedented sinking of Allied merchantmen by German U-boats that the value of the smoke screen as a means of baffling an under-water attack was fully realised. Convoy guards were supplied with the necessary appliances for emitting the fumes with which to cover the movements of the ships under their protection, and so successful was this method of blinding attacking submarines that within a few months thousands of transports, food-ships and warships had been equipped.

When a submarine proclaimed her presence in the vicinity of a convoy either by showing too much of her periscope or by a misdirected torpedo, the guard-ships on the flank attacked immediately dropped their smoke buoys as they continued moving at full speed. By this means an impenetrable optical barrier was interposed between the attacking submarine and the fleet of merchantmen under convoy. When thus shielded from attack—a submarine values her small stock of torpedoes (six to ten) too highly to risk the loss of one or more on something she cannot even see—the mercantile fleet altered course so as to present their sterns to the attacking U-boat, while certain prearranged warships belonging to the escort proceeded to the attack with guns and depth charges.

This means of masking the movements of ships—by no means new in naval warfare—was employed with conspicuous success in the operations of Allied squadrons off Zeebrugge. Individual merchantmen, when attacked by one or more submarines, often threw out a smoke screen to avoid destruction by the big surface guns of the more modern German craft, and its use to cover the movements of transports was very frequently resorted to.

The use of camouflage, or the deceptive painting and rigging of ships, came first into being owing to the method employed by submarines for judging the speed of passing surface ships by the white wave thrown off from their bows. It is of the utmost importance for the commander of an under-water warship to correctly judge the speed of the vessel he is about to attack before discharging a torpedo at her. If the estimated speed is too high the torpedo will, in all probability, pass ahead of the moving target, and if it is too low it will run harmlessly astern.

To cause this to happen as frequently as possible, and valuable torpedoes to be wasted—even if the attacking submarine herself could not then be discovered and destroyed—it became advisable to paint imitation white waves on the bows of slow-moving ships in order to give the appearance of speed.

So successful was this simple form of deceptive paint-work that a special camouflage section of the naval service, with an eminent artist as its director, was formed, and all kinds of grotesque designs were painted on the broadsides and superstructures of almost every British merchantman operating in the submarine danger zone.

There was method and meaning in the seemingly haphazard streaks of black, green, blue and white. When looked at from close range only a jumble of colours could at first be seen, but if the distance was increased the effect became instantly apparent. In some cases the deceptive decoration caused big ocean liners to appear small and insignificant. In others it gave the appearance that the vessel was sinking; while quite a favourite ruse was to cause the vessel to appear as if she was travelling in the opposite direction to that which she really was. Two-funnelled ships became single-funnelled, when viewed from a distance or in a dim light, by the simple expedient of painting one funnel black and the other light grey. Liners with tiers of passenger decks had the latter obscured by contrasts of colouring which were really masterpieces of deceptive art. In fact so deceptive became almost every ship in the dim light of dawn and dusk that collisions were often narrowly averted.

It frequently occurred that paint alone was not sufficient to disguise a ship, and woodwork and canvas were resorted to. Big guns were made of drain-pipes and shields of the wood from packing-cases. Cargo boats were given the appearance of cruisers, and cruisers reduced to the appearance of cargo boats. In this way hostile submarines were induced to attack ships, thinking them unarmed and helpless, when in reality they were small floating forts. But at this point simple camouflage ceases and the famous Mystery Ship begins. Before closing this chapter, however, it must be pointed out that camouflage only came into being when the German U-boats commenced their ruthless submarine warfare.

CHAPTER VII

MYSTERY SHIPS

The mystery ship was not a specially constructed war vessel, such as a destroyer or cruiser, but merely a merchantman converted into a powerfully armed patrol ship, camouflaged to give the appearance of genuine innocence, but with masked batteries, hulls stuffed with wood to render them almost unsinkable, hidden torpedo tubes, picked gunners, a roving commission and a daring commander and crew. Their work was performed on the broad highways of the sea, and they hunted singly or in pairs, often fighting against overwhelming odds with certain death as the price of failure.

The number of these vessels was not large, possibly 180, but their operations extended far and wide. They roamed the North Sea, the Atlantic, the English Channel, the Mediterranean, the Arctic Ocean and even the Baltic, but until challenged were quite unknown to all other vessels of the Allied navies. Theirs was a secret service, performed amidst great hardships, with no popular applause to spur them on.

As all "Q" boats—as they were officially called—differed from each other in size and armament, any description given here can only be taken as applying to one or more vessels with which the writer was personally familiar. Some of these so-called mystery ships were old sailing schooners, others fine steamships, while quite a number were converted fishing smacks, drifters and trawlers, the method being to give the prospective commander a free hand in the conversion of his ship from a peaceable merchantman to a camouflaged man-of-war, and many were the ingenious devices used.

One vessel fitted out for this desperate duty at a Scottish base was a steamer of about 400 tons burden. She was armed with a 4^.7 quick-firing gun hidden in a deck-house with imitation glass windows, the sides of which could be dropped flat on to the deck for the gun to be trained outboard by simply pressing an electric button on the steamer's bridge. Two life-boats, one on each side of the aft deck, were bottomless, and formed covers for two additional 12-pounder guns. A false deck in the bow shielded a pair of wicked-looking torpedo tubes, each containing an 18-inch Whitehead ready for launching; and the crew for each gun were able to reach their respective weapons, without appearing on deck, by means of specially constructed gangways and hatches. The very act of dropping the sides of the aft gun-house hoisted the White Ensign, and technically converted this unsuspicious-looking merchantman, which asked only to be allowed to pursue its lawful vocation on the high seas, into a heavily armed warship.

This "Q" boat had, when met and challenged by the writer's ship, already accounted for no less than three German submarines which had opened the attack from close range, thinking her defenceless.

Another smaller mystery ship was a converted fishing drifter with a single 12-pounder gun on a specially strengthened platform fitted in the fish-hold, which had been cleaned, matchboarded and painted to provide accommodation for the crew of picked gunners. This little ship had no torpedo tubes and the muzzle of her gun was hidden beneath fishing nets.

There were, however, some very large and elaborately fitted "Q" boats. These had specially constructed torpedo tubes low down in the hull, masked 4^.7-inch guns in more than one position, special chutes for depth charges, coal bunkers arranged round the vital machinery to protect it from shell-fire, and, moreover, were filled with wood to make them almost unsinkable even if torpedoed.

Each such vessel was provided with a "panic party," whose duty was to rush to the life-boats when the ship was attacked by a submarine. This gave the final touch to the disguise, and often induced the submarine to save further torpedoes by coming to the surface and continuing the assault with gun-fire.

The story of the sinking of the last German submarine in the war by the "Q 19" will give some idea of how these vessels worked. It occurred in the Straits of Gibraltar, about twenty-four hours before the signing of the Armistice. The Q 19 was waiting in the Straits expecting to intercept three big U-boats on their way back to Heligoland. About midnight the first of these craft came along, and sighting the innocent-looking "Q" boat prepared to attack her with gun-fire. For nearly an hour the mystery ship "played" the submarine by pretending to make frantic efforts to escape, but all the time allowing the under-water craft to draw closer and closer.

The "Q" boat was under a heavy fire from the submarine, one shell wounding eleven out of the crew of sixty, another carrying away the mast and a portion of the funnel, but no sign of a gun was yet displayed on board the surface ship. This withholding of fire until the last moment, when the range has become short and the effect certain, is one of the great nerve tests imposed on the crews of all mystery ships. It is an essential of success, for a few wild shots at long range would disclose the fact that the vessel was heavily armed, and the attacking submarine would either sheer off or else submerge and use her torpedoes.

When the chase had been on for about fifty minutes, and the submarine was only 200 yards astern, the "panic party" in the "Q" boat rushed for the life-boats. The shells were now doing serious damage to both hull and upper works, and the submarine was creeping close to give the coup de grâce.

At this, the psychological moment, the order to open fire was given. The collapsible deck-house, shielding the 4^.7 gun, fell away on its hinges. Eleven shots were fired in quick succession, all of which struck the submarine. One blew the commander off the conning-tower and another rent a gaping hole in the vessel's hull. In less than fifteen minutes the fight was over and the last U-boat to be sunk in the Great War of civilisation had disappeared beneath the waters of the Straits of Gibraltar.[4]

CHAPTER VIII

A TYPICAL WAR BASE

Around the coasts of the British Isles there were about forty of these war bases, each with its own patrol flotillas, minesweeping units and hunting squadrons. The harbours, breakwaters and docks had to be furnished with stores, workshops, wireless stations, quarters for officers and men, searchlights, oil-storage tanks, coal bunkers, magazines, fire equipment, guard-rooms, signal stations, hospitals, pay offices, dry docks, intelligence centres and all the vitally necessary stores, machinery and equipment of small dockyards.

To do this in the shortest possible time, and to maintain the supplies of such rapidly consumed materials as oil fuel, coal, food, paint, rope and shells for perhaps a hundred ships for an indefinite number of years, it was often necessary to lay down metals and sidings to connect the base with the nearest railway system. At many bases secure moorings had also to be laid by divers, and the channels and fair-ways dredged. The larger bases also required temporary shore defences, and booms arranged across the harbour entrances to prevent hostile under-water attacks.

Then came the problem of finding the personnel. The ships had already been provided for, but to keep them in fighting condition, and for the work of administration, it was necessary to have a shore navy behind the sea-going units. An admiral from the active or retired list was appointed to each base as the "Senior Naval Officer." Then came additions to his staff in the persons of executive and engineer commanders, officers of the Reserve, chaplains, surgeons and paymasters. With these departmental chiefs came their respective staffs of warrant officers, petty officers, wireless operators, engine-room artificers, motor mechanics, shipwrights, carpenters, smiths, naval police, signalmen, storekeepers, sick berth attendants and parties of seamen. Finally, a generous supply of printed forms and train-loads of stores.

This then, in brief outline, was the material which went to form the war bases of the auxiliary, or anti-submarine, fleets. In many cases much more was required, especially at such important depôts as Dover, Granton and Queenstown. About the permanent dockyards, like Portsmouth, Devonport and Rosyth, or the Grand Fleet bases, nothing need be said here, because they do not come within the scope of this book. The same may also be said of that desolate but wonderful natural anchorage, Scapa Flow, the headquarters of the Grand Fleet in the misty north. Each of these mammoth naval bases had an auxiliary base for anti-submarine and minesweeping divisions.

With a knowledge of these essentials a more detailed description of a typical war base and the work of its staff may prove of interest. Taking as an example a large depôt, supplying all the needs of over a hundred erstwhile warships, and situated in the centre of the danger zone, we find a central stone pier on which has been erected a perfect maze of wood and corrugated iron buildings, with the tall antennæ of a wireless station, a little look-out tower and a gigantic signal mast from which a line of coloured flags is aflutter in the sea breeze. The shore end of the pier is shut off from prying eyes by a lofty wooden palisade with big gates, in one of which is a small wicket. Outside a sentry with fixed bayonet paces to and fro.

The first person inside the sacred precincts to greet the stranger is a keen-eyed "Petty Officer of the Guard." When the credentials have been examined the visitor is sent under the guidance of a bluejacket to the "Officer of the Day," whose "cabin" is inside the maze of corrugated iron and weather-board. The doors flanking the passages traversed display cryptic lettering, such as I.O. (Intelligence Office), S.R. (Signal Room), S.N.O. (Senior Naval Officer), "Commander" (usually the second in command of the base), P.M.S.O. (Port Minesweeping Officer), C.B.O. (Confidential Book Office), M.L.Com. (Motor Launch Commander), O.O.W. (Officer of the Watch), "Officers only" (the wardroom and gunroom combined), and, finally, the O.O.D., or the abode of that much-worried individual, the Officer of the Day, whose duties happily terminate when his twenty-four hours of administrative responsibility are over, only, however, to return in strict rotation.

Again comes an apologetic examination of credentials, possibly followed by a few minutes with the admiral commanding, and then the grand tour commences. First come the ships lying alongside the stone pier, with their short funnels belching black and very sooty smoke. These are the "stand-off" units, whose crews are enjoying a brief few hours ashore after days or weeks out on the dangerous seas beyond. Big drums of oil are being lowered by ropes on to their decks. The sound of hammering comes from more than one engine-room, where machinery is being overhauled. On the decks of several, men with little or no resemblance to the clean "Jacks" of the naval review are fondly polishing, painting or greasing the long grey barrels, steel breech mechanism, or the yellow metal training wheels of guns. Others are cleaning rifles, which have recently been used with special bullets for sinking floating mines. One ship is washing down decks after coming in late from night patrol; another is receiving its three-monthly coat of grey paint; while on to the deck of a whaler—black and ominous-looking—hundredweights of provisions in boxes and bags are being lowered from the quay.

Astern of these lie two tiers of light grey spick and span motor launches, their decks spotlessly white, and their small canvas and glass screened wheel-houses ill concealing polished brass indicators, Morse signalling key, electric switches, binnacles and other paraphernalia. Behind these lie the 40-knot coastal motor boats, like miniature submarines, with torpedoes in cavities in their aft decks, and little glass-sheltered steering-wells. Further towards the head of the pier is a line of big flat Scotch motor drifters, built for rough weather with 9-inch timbers, their decks a maze of wire nets, glass floats and brick-red chemical canisters.

On the opposite side of the pier, in front of the S.N.O.'s cabin, lies a big grey yacht with four 12-pounder guns and an anti-aircraft weapon pointing over the sky-reflecting water. Lying out in the basin are big minesweepers, looking more like pre-war third-class cruisers, two slim-looking dark grey destroyers, a dredger and a few nondescript craft.

Inside the first row of iron sheds are stores, with barrels of tar, drums of paint, immense coils of rope and a naval "William Whiteley's"—in which anything from a looking-glass to a ball of string, or a razor to a dish-cloth, can be obtained in exchange for a signed form from the Naval Store Officer, whose cabin near by is a maze of similar forms of all colours.

Then a worried-looking man hurries by and the O.O.D. smiles. "He's the coaling officer, and there's some twenty ships waiting to get alongside to take the beastly stuff aboard," is the laconic explanation.

A cabin marked I.O. is entered—every room is a cabin in a naval base. Here the walls are decorated with innumerable charts with mysterious red lines. A curious device, with the names of all the ships belonging to the base painted on wooden slides, reaches across one side. It is the indicator which shows at a glance the ships at sea and those in harbour, the names of those under repair, the unit to which each vessel belongs and when she goes out or comes in for "stand-off."

This is the Intelligence Office, and signals and wireless messages from the patrols and battle fleets are being almost continuously brought in and carried out by messengers. The Commanding Officer (C.O.) of a minesweeper is making inquiries about tides and the exact position on the chart of a newly located mine-field. Another officer is locking a black patent-leather dispatch-case—he is the King's Messenger or, more correctly, the "Admiralty Dispatch Bearer," who carries to and from London and the fleets all the secret correspondence and memoranda of the Naval War Staff and other important departments. A big safe in the corner of the cabin contains the secret codes and ciphers used when transmitting messages, and two overworked officers are busy at near-by desks translating signals to and from "plain English."

The next cabin contains the admiral's secretary and his staff of writers. Here a flotilla commander is receiving his "sailing orders," without which no ship proceeds on a voyage. Adjoining this is the Pay Office, in which, with the exception of a newly joined recruit mortgaging his pay for two weeks ahead—he knows that he will be at sea for that time—there is a decided air of quietude. The rush in this abode of paymasters comes at the end of each month, when all the officers arrive in a body to demand the meagre fruits of their labours.

Sandwiched between the clean and varnished cabin of the Base Commander, who is "taking" defaulters, and the camp-bedded apartment of the O.O.W. is a most interesting little combined cabin and store, presided over by the Chaplain. Here are piles of woollen socks, cardigans, balaclavas, mitts and other clothes knitted by the thoughtful women of the Empire for their sailor sons. Here seamen are estimating the cold-resisting qualities of different garments—for winter in the North Sea is the next thing to Arctic exploration. Officers are popping in and out to borrow a pile of books—thrice blessed were the senders of these donations. The corner of the cabin is piled with fresh vegetables, but alas! the cry is apples! No exhortations to righteousness adorn the walls, and the chaplain is joking with a big stoker who is distractedly turning over the cardigans in search for one large enough to encompass his massive frame. A signal boy slips in, gets chocolate, gives a breathless thanks and slips out just in time to avoid the playfully raised hand of the P.O. of his ship. Two deck hands, covered in coal dust, put their heads round the door to ask if they can have a bath, and the indefatigable chaplain hands them the keys of the room provided for the purpose by the generous.

Religion here is more practical than theoretical. If a man swears when the "Padre" is present he pays a small fine, which goes to the recreation or other needy fund. The Commander is not immune from this law at the base under review, and has more than once been "heavily fined" for giving his true opinion of German sailors and winter weather.

The next cabin is that of the O.O.W., a seething mass of officers demanding "duty boats" and pinnaces to convey them to and from their ships lying out in the fair-way. Others are expostulating about being ordered to sea during their "stand-off," informing everyone what a rotten service the navy is, crossing-sweeping is a sinecure compared with it. Then a few pass on to the cabin near the men's quarters. Here the "Drafting Officer" is trying to palm off a deck hand on the C.O. of a trawler, who is vainly explaining that he must have a signalman. A telephone rings and news comes from the "Sick Bay" that an engineer has been badly burned and will be unable to go to sea with his ship. The distracted drafting officer searches through his lists of reserves for some competent man to take the place of the casualty.

Peace reigns in the adjoining department, where a grey-haired veteran is issuing charts, "Sailing Directions," "Tide Tables" and "Warnings to Mariners." In the near-by engineer-commander's office worried experts are wrestling with innumerable problems relating to M.L. motors, steam capstans, steam steering gear, electric dynamos, damaged propellers, broken shafts, boiler cleaning and the numerous imperfections of overworked ships' engines.

The Boom Defence staff is placidly serene. The turn of this department comes after a heavy gale has damaged the submarine nets, chains and buoys. The torpedo officers and their "parties" are discussing the best way of moving four of these steel monsters from a neighbouring depôt ship to a new "Q" boat with only a rowing-boat at their disposal—soon the O.O.W. will be called upon to supply a drifter for the purpose.

In the ordnance store a veteran P.O. is trying to make his list of returned brass shell-cases correspond with the number of shells supplied to various ships six months before. He knows the sailors' fondness for shell-cases as ornaments in their little far-away homes, and, failing to make all the figures agree, decides that some must have been "washed overboard."

The Port Minesweeping Officer is discussing with his sea commanders the clearing of a new mine-field laid by U-C-boats within the past few days, when a sudden stir is caused by the arrival of a signal from the wireless room to the effect that one of his vessels has struck a mine in lat. —— long. —— and is sinking. He appeals by telephone to the M.L. commander and in less than ten minutes a flotilla of fast launches is racing at 19 knots to the rescue.

In the Admiral's cabin there is to be a conference of senior officers later in the day to decide on the best means of ridding the seas within that area—and each base has its own area of sea—of a hostile submarine which has been inflicting undue loss upon shipping, its latest victim being a Danish barque.

The combined wardroom and gunroom has some twenty occupants, reading the newspapers and magazines, warming themselves before the two big fires, or talking in little groups. This base has suffered some heavy losses lately, but reference to those "gone aloft" is seldom made, except quietly and a little awkwardly. The talk is of theatres in neighbouring towns, the respective merits of certain types of ships and weapons, the prospects of early leave, the dirty warfare of "Fritz" or the "beauties" of the North Sea in winter.

In this room all questions of rank and precedence are more or less waived. There are, of course, differences, especially when the wardroom, or abode of senior officers, does duty also as a gunroom for the juniors. But here there is camaraderie and an absence of iron discipline, although a sub-lieutenant would be extremely ill advised either to drop the prefix "Sir" or to slap the Commander on the back in an excess of joviality, relying on "neutral territory" to save him from rebuke. It is, however, no uncommon event to see all ranks of officers engaged in a heated debate, or groups of juniors laughing round the fire while their elders are vainly trying to concentrate their minds on the latest Press dispatches. Games are played and glasses clink merrily, but in a gunroom there is a very strict limit as to both time and quantity, though none regarding volume or discordance of sound.

Passing on to the organisation of the flotillas for sea, we find in this large base six minesweeping units, two being composed of fast paddle sweepers and four of trawlers. The former are used for distant operations and comprise nine vessels. They work in pairs, but the extra ship is available to sink mines cut up by the sweeps of the others, and to be immediately ready to beat off submarine attacks.

The trawlers are engaged in sweeping daily the approaches to the harbour and a recognised channel up and down the coast. Their work overlaps with that done by the ships belonging to the neighbouring bases. In this way the "war channel," about which more will be said later, was kept free of mines, and afforded a safe route for ships from the Thames to the Tyne, and in reality to the northernmost limit of Scotland.

This important duty was seldom left unperformed even for a day, except during fierce gales. Often the discovery of a distant mine-field caused many ships to be concentrated on clearing it, and the number available for the "routine sweeps" was consequently reduced, but longer hours of this arduous and dangerous work made up the difference, and the work went on in summer fog and winter snow for over four years.

The anti-submarine patrols were composed of five ships each, under the command of the senior officer of the unit—frequently a lieutenant with the responsibility of a captain. Their work lay out on the wastes of sea lying between England and Germany. It was seldom that the whole five vessels of each unit cruised together, the usual method being to scatter over the different "beats" and rendezvous in a given latitude and longitude at a specified time and date. They were usually able to communicate with each other and with the base on important matters by wireless. Their periods at sea varied from ten days to three weeks, with a four days' "stand off" when they came into harbour. But of this time one day at least was spent in coaling and provisioning the ship ready for the next patrol. This ceaseless vigilance on the grey-green seas of England's frontier was seldom interrupted for more than a few days in the year by impossible gales. Anything short of literally mountainous seas did not prevent the trawler patrols from riding out the storm carefully battened down and with just sufficient speed to keep head to sea.

The drifters were divided into patrol units, boom defence flotillas and under-water or mine-net units. Their work was thus more varied but equally as arduous and risky, as the loss of 30 per cent. of the entire fleet of over 1000 ships affords undeniable proof. The periods of sea duty were similar to those of the trawlers.

The motor launches at each base had some hundred square miles of sea to guard, and hunted in fives. The rough weather these plucky little ships endured in the open sea in mid-winter, the intense cold—for there was no proper heating appliance—and the state of perpetual wetness made their duties among the most arduous in the sea war. Later pages of true narrative will show to the full the work of these gnats of the sea.

In addition to all these flotillas there were convoy ships, whaler patrols, "Q" boats and a number of special duty ships. The work of the former was of the most exacting character, and left the crews of these vessels but little time ashore. In the base under review so arduous were the duties of the convoy ships that it became a matter of self-congratulation for patrol and sweeper officers and men that their ships were not so employed, and this by men who sailed submarine and mine infested seas for an average of 270 days in each year!

It must not be assumed that when in harbour there were no duties to be performed by either officers or men of sea-going ships. They had, on the contrary, to furnish anchor watches, shore sentries, duty crews for emergency pickets, prisoner guards, working and church parties, to attend drills, rifle practice, gun practice and instructional parades. The officers had similar shore duties to perform, which left them little time to rest from the strain of keeping watch and ward on the death-strewn seas.

CHAPTER IX

THE CONVOY SYSTEM

The rapid development of submarine piracy, however, compelled the Admiralty, early in the year 1917, to resort to what was merely a new form of the old system of protecting sea-borne trade. This comprised the collection of all merchant ships passing through the danger zones into nondescript fleets, and the provision of light cruisers, destroyers, torpedo-boats, trawlers and occasionally (for coastal convoys) of patrol launches to escort them. Certain types of aircraft were also frequently used for observation and scouting purposes.

Previous to the adoption of the convoy system a merchantman, whether it was a fast-moving liner or a sturdy but slow ocean tramp, zigzagged through the danger zones with lights out and life-boats ready. Many were the exciting runs made in this way, with shells ploughing up the water around and torpedoes avoided only by the quick use of the helm; but the courage of our merchant seamen was of that indomitable character exhibited now for over three centuries, since the days of Drake, Hawkins, Raleigh and the other sea-dogs of old.

But the danger zones grew wider as the radius of action of newer and larger German submarines increased. At last no waters were immune, from the Arctic circle to the Equator, or from Heligoland to New York.

The hour was one of extreme peril for the sea-divided Empire. To lose several hundred ships, with many thousands of lives and much-needed cargoes of food and munitions, when the valiant armies of civilisation were battling with the Teuton hordes, was bad enough; but if the enemy had been able, by casting aside the laws of humanity and sea war, to compel British ships to remain in harbour or meet certain destruction on the high seas, the result could only have been the complete failure of the Allied cause, the conquest of Europe and the fall of the greatest political edifice since Imperial Rome.

Between the world and these catastrophes, however, stood the undefeated Mercantile Marine and the Allied navies. Councils were held in the historic rooms of Whitehall and the old convoy system emerged from the archives of Nelson's day. The commerce raiders were no longer the canvas-pressed privateers of the sixteenth, seventeenth and early eighteenth centuries, who fought a clean fight, often against great odds, but were submarine pirates of the mechanical age, who only appeared from the sea depths when their victims had been placed hors de combat.

It is an old axiom of war that new weapons of attack are invariably met by new methods of defence. So it was with the convoy system which gave the death-blow to German hopes of a submarine victory. In order to understand this new method it is necessary to study the accompanying diagram, which, however simple it may appear on paper, is extremely difficult to carry out in practice.

At each great port there was a convoy officer, who assembled the merchant ships when they had been loaded and explained to their captains the exact position each ship was to occupy when the fleet was at sea. Printed instructions were handed round urging each vessel to keep its correct station, stating the procedure to be adopted in the event of an engine breakdown, giving the man[oe]uvres which were instantly to be carried into effect when an attack was threatened, and finally the special signals arranged for communication between the merchantmen and their escort by day and by night.

The number of vessels composing a convoy varied, but often exceeded twenty big cargo ships, carrying some 120,000 tons of merchandise, or six liners, with 20,000 troops on board, while the escorting flotilla consisted of a light cruiser, acting as flag-ship, six destroyers, two special vessels ("P" boats) towing observation airships, and some eight or ten trawlers, with possibly one or more seaplanes and several M.L.'s for the first few miles of the voyage. The destroyers were spread out ahead and on the flanks of the fleet, and by using their greatly superior speed were able to zigzag and circle round the whole convoy.

In the event of an attack the whole fleet turned off from the course they were steering at a sharp angle, showing only their sterns to the U-boat. A destroyer acted as rearguard to prevent any of the convoyed ships from straggling. When the fleet had arrived at a rendezvous far out in the open sea, where the danger of a submarine attack was much less, the escort handed over their charges to one or two ocean-going cruisers, which stayed with the merchant ships throughout the remainder of their voyage.

The escorting flotilla then cruised about in the vicinity of the rendezvous until an incoming convoy appeared. These ships were then taken over from their mid-ocean cruiser guard and escorted back through the danger zone to port, and so the game of war continued until months became years.

All this may sound straightforward and quite simple, but there were difficulties, to say nothing of dangers, which made it a most arduous operation. First came the speed problem. Every merchant ship differed in this important respect, so the speed of the slowest unit became the speed of the entire fleet, and this reduction made an attack by under-water craft much easier of accomplishment. Hence the call for "standard ships," which is a point that should be borne in mind by future generations as a safeguard against blockade. Then came the question of destination, which increased the number of escorting flotillas, and especially ocean cruiser guards, required for a given number of cargo ships. Next there was the loading and unloading to be considered, involving long hours and hard work by the men on the quaysides. This great difficulty was one of the reasons for the formation of docker battalions. Coaling such big fleets by given times caused many grey hairs to appear where otherwise they would not have been. Finally there was the danger of mines having been laid in the fair-ways leading to the port, which necessitated every convoy being met by special vessels to sweep the seas in front of each incoming and outgoing fleet.