STORMING THE MOLE.
Drawn by Charles De Lacy from details supplied by the Author
THE BLOCKING OF
ZEEBRUGGE
BY
CAPTAIN A. F. B. CARPENTER, V.C., R.N.
WITH AN INTRODUCTION BY
ADMIRAL EARL BEATTY
AND APPRECIATIONS BY
MARSHAL FOCH, REAR-ADMIRAL SIMS
AND
COUNT VISART
(BURGOMASTER OF BRUGES)
WITH ILLUSTRATIONS
BOSTON AND NEW YORK
HOUGHTON MIFFLIN COMPANY
The Riverside Press Cambridge
1922
COPYRIGHT, 1922, BY ALFRED F. B. CARPENTER
ALL RIGHTS RESERVED
The Riverside Press
CAMBRIDGE — MASSACHUSETTS
PRINTED IN THE U.S.A.
TO
THE MAN-IN-THE-STREET
INTRODUCTION
BY ADMIRAL EARL BEATTY
In appreciating the military reasons which directed the operations connected with the blocking of Zeebrugge, it is desirable to recall to mind the general naval situation at the beginning of 1918.
Briefly stated, the German High Seas Fleet was contained within the waters of the Heligoland Bight by the British Grand Fleet, whilst German submarines were engaged on vast operations, having for their object the stoppage of the trade of Great Britain, and interference with our lines of communication.
In the face of such an attack, the aim of Great Britain was either to destroy the enemy submarines, or, failing destruction, to prevent their egress from their bases. Convoy operations, patrol operations, and mining operations in all seas were carried out to achieve the former aim, and accomplished great results.
But enemy submarines continued to be built almost as rapidly as they were destroyed. It was essential, therefore, to take what measures were possible to render useless their bases and interfere with their freedom of exit, and it was with this military object that plans for the blocking of Zeebrugge were initiated.
Emphasis has been laid on the military reason which underlay this operation, because an erroneous impression has existed in some quarters that the Zeebrugge operations were more in the nature of an offensive designed to lower the morale of the enemy and enhance that of the British Navy, which, as a whole, had little opportunity of coming to grips with the enemy.
Whilst these moral results undoubtedly were felt after the operation, they were not the military reasons, reasons alone which justified so complex and difficult an undertaking, reasons which were never lost sight of during the planning and carrying out of the operations.
The plan was surely laid; simple in general design, details were worked out with foresight and exactitude. The factors of surprise, mystification, and diversion were utilised to the utmost. The resources of science were given full scope. Training to carry out the plan proceeded with energy and understanding, co-ordination and co-operation being apparent throughout. It was carried out with determination.
In Captain Carpenter's book we are let into the full secret, and are led step by step through the various phases referred to above, which were to be crowned by the glorious achievement of St. George's Day, 1918. His pages bring out once again the moral and military virtues of the British Navy, Officers and Men. They demonstrate that the spirit which existed in our Naval Wars of past centuries, wars which laid the foundation of the Empire, remains undiminished in the naval personnel of to-day.
It is for us to ensure that these glorious traditions are understood by all, and in being understood are handed on to those who come after us. This book, in placing on record the matchless qualities displayed by all concerned in the blocking of Zeebrugge, I welcome for this purpose.
BEATTY
Admiral of the Fleet
19th July, 1921
APPRECIATION
BY MARSHAL FOCH
C'est dans un sentiment de solidarité que s'est réalisée l'union des Alliés, en 1914, quand la cause de la Civilisation s'est trouvée menacée.
A tous les moments critiques de la guerre, l'union s'est ainsi resserrée devant le danger, et lorsqu'il s'est agi de fermer un des repaires d'où les sousmarins ennemis menaçaient les communications vitales des Alliés, dans une manoeuvre splendide, avec un esprit commun de sacrifice absolu, le port de Zeebrugge a été attaqué et definitivement fermé.
Le Commandant du Vindictive a tenu à rappeler les détails de l'opération dans laquelle il a joué un rôle si brillant, et son livre constituera un précieux enseignement et donnera aux générations futures un exemple splendide.[[1]]
F. FOCH
[[1]] When in 1914 the cause of civilisation was menaced, it was the instinct of solidarity that brought about the Union of the Allies.
At every critical moment of the war, in the face of peril, this bond was renewed; and when it became a question of closing one of the lairs from which the enemy submarines threatened the vital communications of the Allies, the port of Zeebrugge was attacked and closed once and for all by a superb manoeuvre involving a common spirit of supreme sacrifice.
The Captain of the Vindictive has undertaken to tell in detail the story of the action in which he played so brilliant a part, and his book will afford a valuable record and set forth a fine example to future generations.
APPRECIATION
BY REAR-ADMIRAL SIMS, U.S.N.
Few incidents of the Great War had a greater influence in inspiring enthusiasm in the fighting forces and increasing their morale than the successful attack upon Zeebrugge; and it will long remain as an example of what can be accomplished by the thorough co-ordination of the elements of a sound plan with the various limiting conditions of place, time, state of sea and air, and the material equipment suitable and available.
The reader of this volume will at once be struck by the painstaking care with which it was necessary that each detail be worked out, and each unit assigned its particular task to be executed at a specified time and place. Also that the amount of detail was necessarily so great, and their dependence one upon another so vital to ultimate success, that the whole may be compared to a complicated mechanism so designed to meet peculiar conditions that the failure of any part—any unit or group—or a material change in any of the conditions, would have deranged essential elements of the plan and might have jeopardised the success of the expedition.
But the principal lesson to be learned from the attack is not so much the thoroughness of the preparation and training and the efficiency of the weapons, essential as they of course were, as it is the influence of the spirit and the initiative and loyalty of the personnel that carried it out. These elements supplied the "steam," the flexibility, and the lubrication that ensured the harmonious working of the whole mechanism of which they were the soul. The basic principle was the splendid morale of the personnel inspired by the high character of its leaders.
Apart from the great interest of this narrative to the laymen, as a military exploit of the most brilliant character, and an inspiring story of heroism in war, it will always prove of great value to those military men of both branches of the service who realise the tremendous influence of the morale of their forces—the confidence in the ability of the leader which encourages initiative and inspires the highest type of loyalty.
WM. S. SIMS
APPRECIATION
BY COUNT VISART
(Burgomaster of Bruges)
Ainsi que tous mes concitoyens j'ai appris avec une grande satisfaction que la fameuse attaque de Zeebrugge par le Vindictive allait faire le sujet d'un livre publié prochainement par Capitaine Alfred F. B. Carpenter, un des héros qui ont pris une part glorieuse à cet exploit.
Cette entreprise de la Marine de Guerre Anglaise a été assurément une des faits de guerre les plus extraordinaires des temps anciens et modernes. Elle a été accompliée avec une énergie et une audace qui a déjoué toutes les prévisions des Allemands.
Ainsi en dépit de toutes les difficultés, de tous les dangers, et de pertes cruelles, l'assaut prodigieux du mole a jeté l'épouvante parmi les ennemis et en même temps le Vindictive et les bateaux qui le suivaient ont embouteillé dans leur repaire les abominables U.B.
La cannonade entendue à Bruges nous avait déjà donné l'éveil et bientôt les rumeurs que les Allemands n'avaient pu intercepter et la consternation qu'ils tentaient vainement de dissimuler nous ont appris que l'Angleterre avait frappé un grand coup. Un tel événement releva tous nos courages.
Nous espérons qu'à Zeebrugge, sur le territoire de Bruges, un magnifique monument immortalisera ce fait inoui, mais c'est avec le plus grand intérêt que nous connaîtrons par le livre de Capitaine Carpenter toutes les circonstances de cette histoire héroïque et les noms des hommes qui ont donné une nouvelle gloire à la Marine Anglaise.[[2]]
AMIDER VISART
Bourgemestre de Bruges
[[2]] It was with great satisfaction that I and all my fellow citizens learned that the famous attack on Zeebrugge by the Vindictive was to be the subject of a book, to be published in the near future, written by Captain Alfred F. B. Carpenter, one of the heroes who took a glorious part in that exploit.
This enterprise of the British Navy was assuredly one of the most extraordinary feats of war in both ancient and modern times. It was accomplished with such energy and audacity as to baffle all the German plans.
In spite of all the difficulties, dangers, and cruel losses, the wonderful assault on the mole created consternation amongst the enemy; and the ships which followed the Vindictive bottled up the abominable submarines in their base.
The sound of heavy firing heard in Bruges had already warned us; later, the receipt of rumours which the Germans had been unable to intercept, and their consternation which they were vainly endeavouring to conceal, proved to us that England had struck a mighty blow. Such an event renewed our courage.
We hope that at Zeebrugge, which is within the territory of Bruges, a magnificent memorial will eventually immortalise this unprecedented action, and it is with the greatest interest that we shall learn from Captain Carpenter's book all the circumstances of this heroic episode and the names of the men who added this new glory to the British Navy.
AUTHOR'S PREFACE
As a result of having delivered many lectures, under official auspices and in compliance with private invitations, on "The Blocking of Zeebrugge," the author has received several requests to record the story in more permanent form. Underlying these requests there appears to be a feeling that first-hand accounts of enterprises in the Great War should be of some value towards preserving that spirit which rallied all classes of individuals in the British Empire, in the Allied Countries, and in the United States of America, to the common cause of upholding civilisation in the face of danger. That opinion, indeed, has been openly stated to the author in Great Britain, by leading members of the educational profession and of the Church, by naval and military officers and others. Opinions of a similar type also have been received from the United States, where, during a recent series of visits to many of the larger cities, the author personally experienced that solid friendship for Great Britain which is sometimes hidden beneath surface irritations of a political nature.
Misunderstandings must occasionally arise between communities and between the members of any single community; they readily take root and develop into serious argument where the existence of a common cause is forgotten. For that reason the author feels that the above-mentioned opinions are not without foundation. Whilst attempting to show that co-operation between the several units of a fighting force and confidence between superiors and subordinates are important factors towards success in war, he has made this humble endeavour to induce the belief that co-operation and confidence in other walks of life are no less necessary.
There is danger of this blocking enterprise being allotted a false position in the contemporary histories of the late war owing to the somewhat prevalent custom of describing war operations with little reference to the various considerations, factors, and events which gave them birth.
The man-in-the-street is sometimes carried away by enthusiasm or despondency, as the case may be, when unexpected events occur during hostilities; he is apt to give little thought to the "why" and "wherefore" of the occurrences. That fact has been exemplified clearly enough with respect to this particular event, for, on all sides, one heard the public verdict, given in the colloquial vulgarism of the period, that the affair was a fine "stunt." The word "stunt," as unmusical to the ear as it was offensive to those concerned in the operations, has been defined as "a voluntary act, spectacular, usually unnecessary, sometimes involving risk, and designed to attract attention." However, the man-in-the-street meant well, and, after all, could justifiably plead that his lack of education on naval matters was to blame. The author has therefore addressed this book to the man-in-the-street, and has endeavoured to "put him wise," as our cousins across the water are in the habit of remarking.
The official despatches dealing with the blocking operations on the Flanders coast were published early in 1919, and, as far as despatches can go, gave a splendid account of the enterprise forming the subject of this book. But despatches are strictly limited in length and necessarily deal more with cold-blooded statements of fact than with psychological aspects. When one reads despatches of the great leaders of the past concerning the operations in their campaigns one cannot fail to notice the almost complete absence of any reference to the moral factor in war. Yet Napoleon himself declared, "The moral is to the physical as three is to one." Material results can easily be gauged under peace conditions, whereas moral effect on human nature in war is only discoverable from one's own war experiences, which are necessarily limited, and from the experiences of others as set forth in the historical records of past wars. It was partly for that reason, presumably, that Napoleon studied the campaigns of Cæsar and Hannibal although their instruments of war were long since out of date.
The usual reasons for the omission of the moral factors from despatches are twofold. Firstly, the leader from whom the despatch emanates may consider it inadvisable to publish his preconceived ideas as to the eventual effect of the operations on the morale of the enemy; this concealment is especially necessary if the despatch is published before the declaration of peace. Secondly, the writer of the despatch is often unaware, at the time of writing, of the effect already obtained against the enemy's morale; such effects may not be discoverable for many months after the operations have been concluded. Under certain circumstances it may also be temporarily inadvisable to present to the enemy, through the medium of despatches, information concerning psychological effects on one's own personnel. These omissions, therefore, must not be taken to infer that the moral factors were ignored. It is clear, then, that post-war accounts of operations may be far from superfluous whether considered from the point of view of the man-in-the-street or that of the student of war.
Without some conception of the strategical situation arising from the German occupation of the Flanders coast it would be difficult to grasp the true nature of the enterprise described herein. An examination of the strategical outlook alone, however, would be insufficient. The geographical and hydrographical, and even the meteorological, situations largely influenced the choice of tactical methods to be pursued for the attainment of the object in view. It is therefore important to consider the situation from these various standpoints in some detail.
The book has been divided into two parts. Part I deals with the Situation, the Object, the General Plan for the attainment of the Object, the Preparatory Work involved, and the various occurrences up to the eve of the Attack. Part II describes the events which occurred during the operation itself, and includes some consideration of both the material and moral results of the enterprise and the lessons to be drawn therefrom.
For the illustrations the author is much indebted to the Admiralty, Air Ministry, Imperial War Museum, and Press, to whom he makes this grateful acknowledgment.
With regard to the personal side of the story, it may be as well to point out that many of the officers and men concerned were mentioned in the official despatch; that fact lessens one of the difficulties attached to the author's task. A compromise between the purely impersonal attitude and the very natural desire to render full justice to each individual, regardless of the reader's patience, has been aimed at.
The author trusts that the reader will be tolerant of omission and repetition, and will forgive the rather obvious shortcomings of a literary nature which, alas, appear all too frequently in the book.
ALFRED F. B. CARPENTER
8th March, 1921
CONTENTS
PART I
[Introduction by Admiral Earl Beatty]
[Appreciation by Marshal Foch]
[Appreciation by Rear-Admiral Sims, U.S.N.]
[Appreciation by Count Visart]
I. [The Strategical Situation. The German Bases in Flanders. The Conception of the Plan]
II. [The Local Situation. The Local Defences]
III. [The Outlying Obstacles. Considerations of Salvage]
IV. [Past Experience. Smoke Screens. The Chances of Success]
V. [Planning The Operation. Matters Affecting the Plan. Attacks on the Mole]
VI. [The Vessels Involved: Their Duties. The Rescue Work]
VII. [Matters affecting the Passage. The Supporting Forces. The German Sea-Forces. The Preparatory Work]
VIII. [The Personnel. Secrecy. Training. Some Personalities]
IX. [The Waiting Period. The Volunteering Spirit]
X. [Meteorological and Tidal Conditions. Visibility]
XI. [The Orders and Instructions. The Time Factor]
XII. [The First Attempt. The Return to Harbour]
PART II
I. [The Start. The Oversea Passage]
II. [The Approach]
III. [The Commencement of the Attack]
IV. [The Fight on the Mole. H.M.S. Iris]
V. [The Attack on the Railway Viaduct]
VI. [The Smoke Screening. Subsidiary Attacks]
VII. [The Work of the Blockships]
VIII. [The Retirement]
XI. [Some Remarks on the Enterprise]
Appendix. [A List of Vessels and Craft in the Operations]
ILLUSTRATIONS
[Storming the Mole] . . . . . . . . . _Frontispiece_
Drawn by Charles De Lacy from details supplied by the author
[Captain Alfred F. B. Carpenter]
[A Portion of the German Battery on the Lighthouse Extension of the Mole]
[View of the Canal Entrance with its Curved Piers]
[Aerial Photograph of the Canal Entrance]
[The Northeastern End of the Mole]
[The Blockships fitting out for the Enterprise]
[H.M.S. Vindictive before Fitting Out]
[A Portion of the Broad Part of the Mole]
[The Outer Wall, Showing the Parapet Pathway Sixteen Feet Above The Floor of the Mole]
[H.M.S. Vindictive's Specially Constructed Gang-Ways]
[H.M. Ships Iris (right) and Daffodil]
[Lieut.-Col. Bertram N. Elliot]
[Lieut.-Commander Arthur L. Harrison]
[Wing-Commander Frank A. Brock]
[Vice-Admiral Sir Roger J. B. Keyes] (missing from book)
[Diagrammatic Sketch of the Attack]
Drawn By Charles De Lacy From Details Supplied By The Author
[H.M.S. Vindictive's Bridge and Flame-Thrower Hut (right)]
[The Fight on the Mole]
Drawn by Charles De Lacy from details supplied by the author
[Lieut. Claude E. K. Hawkings]
[Commander Valentine F. Gibbs]
[Aerial Photograph taken through the Clouds a Few Hours after the Enterprise]
[The Three Blockships shortly after the Attack]
[The Western Side of the Blocked Channel]
[The Eastern Side of the Blocked Channel]
[H.M.S. Vindictive at Dover after the Attack]
[H.M.S. Vindictive on her Return to Dover]
MAPS AND PLANS
[Plan of Canal Entrance Channel]
[Sectional Sketch of Sunken Blockships]
[Section of the Mole through No. 3 Shed]
[Specimen Diagram for ascertaining Available Period]
THE BLOCKING OF ZEEBRUGGE
PART I
THE BLOCKING
OF ZEEBRUGGE
CHAPTER I
THE STRATEGICAL SITUATION. THE GERMAN BASES
IN FLANDERS. THE CONCEPTION OF THE PLAN.
The main function of a navy in war is that of obtaining the command of the sea. The purpose for which such "command" is desired is the utilisation of the sea-lines of communication and the denial of the same to the enemy.
Soon after the commencement of the war in 1914 the sea-lines of communication across the English Channel assumed considerable, if not paramount, importance for the transfer of personnel and material from Britain to the Allied forces in France. It was equally incumbent on the navy to maintain the trans-Atlantic and other lines of communication along which the necessities of life and war were carried to the Allies in all theatres of war.
The Strategical Situation
The first step towards obtaining "command of the sea" is the removal of the obstacles which stand in one's way. In this particular case the main obstacle (admittedly constructed for the purpose) was the German High Seas Fleet. Thus the first duty of the British Grand Fleet was that of destroying the so-called High Seas Fleet, or, if destruction was found to be impracticable, of reducing it to inactivity. The German Fleet was fully alive to that fact, and, almost throughout the war, hid themselves away in their naval bases under the protection of their coast defences. Thus, as events showed, the High Seas Fleet did not prove to be a very serious obstacle to our Command of the sea; but, and this fact is easily forgotten, we could not foresee the continuance of their ineptitude and lack of spirit. The German submarines, however, were a formidable obstacle, indeed. It is unnecessary to reiterate what is already common knowledge on that point.
Submarines, by their nature, have certain limitations. Except in the case of the submarine cruisers, which only materialised in the latter part of the war, such craft are considerably hampered in their movements by their comparatively small radius of action. Owing to the geographical situation of Germany, her submarines were forced to expend an important percentage of their fuel during the outward and homeward voyages between their bases and the trade routes. This expenditure cannot merely be judged by the distances which had to be traversed; the expenditure of fuel in the submarine bears some relation to the whole circumstances of the voyage.
The endurance of the personnel is another important factor, and is similarly affected by the circumstances under which they are employed. For instance, in waters patrolled by enemy vessels, high speed must always be readily available and the strain on the personnel, consequent on the danger of sudden attack from surface craft, aircraft, or other submarines, to say nothing of the presence of mine-fields, is increased. Thus the longer the passage that the German submarines were forced to undertake in comparatively narrow and dangerous waters—such as the North Sea—the less work could they do on our more important trade routes. That statement is closely connected with the subject of this book.
It did not require very much intelligence on the part of the German Admiralty to realise that the possession of bases on the Flanders coast would greatly facilitate their submarine campaign owing to the consequent reduction of the voyages to and from the trans-Atlantic, or Channel, trade routes. Flanders was therefore used, as will be explained later in detail, to provide advanced bases for German submarines.
The coast of Flanders lent itself to other naval uses. In addition to the guerre-de-course tactics of the enemy—i.e., the direct attack on Allied merchant vessels—it was always open to Germany to take their whole main fleet to sea for the purpose of seeking advantageous conditions for bringing a portion of our Grand Fleet to action.
Movements of modern fleets under war conditions necessitate the use of various types of small craft to precede them—e.g., mine-sweepers for clearing channels for the fleet to pass through, destroyers for supporting the mine-sweepers and for driving back the enemy's small craft, light cruisers for scouting purposes, etc. Mine-sweepers and torpedo craft, by virtue of their small size, are unable to keep the sea for long periods. It will therefore be realised that, in the event of the High Seas Fleet putting to sea for operations in southern waters, the Flanders coast provided Germany with an advanced base from which their light craft could operate.
The German torpedo craft based in Flanders, therefore, would be able to serve a double purpose, viz., that already mentioned and that of attacking our patrol craft, our coast and our merchant vessels when opportunity offered. The mine-sweepers could also serve a double purpose in that they were required to sweep channels for the ingress and egress of submarines based in Flanders whilst being suitably placed for sweeping duties in advance of the main fleet. That Flanders was also suitable for aircraft bases is as well known as it is obvious; but it may not be generally understood that such aircraft would also be of special value to the main fleet under the conditions stated above. Thus, to sum up, the occupation of the Flanders coast by the German sea forces would be of treble value—to provide, firstly, a base for the submarines employed on commerce destruction; secondly, a base for the advanced flotillas and aircraft operating in conjunction with the main fleet in the event of the latter coming south; and, thirdly, a base from which to attack our southern coasts or sea-patrols and from which to indulge in air raids against British and French territory.
The foregoing consideration of the possible uses of Flanders to the German Navy shows the inherent value of an advanced base in that locality; the intrinsic value obviously depended upon the existence of suitable harbours for use as bases. Let us now examine the geographical situation.
CHART SHOWING THE RELATIVE POSITIONS OF DOVER, ZEEBRUGGE, HELIGOLAND, AND THE EXITS FROM THE NORTH SEA.
In the latter part of 1917 the Flanders coast, as far westward as Nieuport, was in the possession of the Germans. The northern extremity of the line separating the German and Allied armies was situated approximately on the Yser Canal, which emanates from Nieuport harbour. The latter was dominated by the gun-fire of both armies; its use was, therefore, denied to both. The only other harbours on the coast of Flanders were Ostende, Blankenberghe, and Zeebrugge. These will be described in some detail presently.
The Flanders Coast
The Flanders coast consists mainly of flat country barely elevated above the level of the sea. Sand-hills along the shore act as a barrier between the sea and the land. Parallel to the shore the tidal current runs to and fro with considerable velocity. The tendency for the tidal current to wash away the sand from the shore is partially countered by the use of groynes, such as are similarly used to maintain our own coastline in many parts of England. Although the groynes on the Flanders coast are carried well out into the sea—they are often 100 yards in length—the movement of sand along the coast is very considerable, and, as will be explained later, has a strong influence on the harbour situation in that locality.
The approaches to the coast are beset with shoals reaching to a distance of eight miles from the land. These shoals have always provided serious obstacles to navigation. During times of peace the charts of this locality had been kept corrected by virtue of continual surveying. The shoals were frequently moving and new shoals appeared from time to time. The channels required almost constant dredging. For obvious reasons during the occupation of Flanders by the Germans it was not possible for the Allies to continue either the surveying or the dredging.
Before the war navigation off this coast required the use of many facilities such as buoys and lighthouses. At the best of times buoys are not very dependable as navigational aids owing to their tendency to break away in heavy weather or to drag their anchors along the bottom. Their positions need to be "fixed" from time to time by means of angles to shore objects, or by methods of astronomical observation, and then compared with the positions shown on the charts. Lighthouses, however, unless they are of the small type without lighthouse-keepers, are more efficient aids to the navigator. During the war the lighthouses east of Nieuport were only used by the Germans during short periods when specially required for their own craft; the majority of the buoys were withdrawn and the remainder were moved to new positions which were frequently altered to prevent the Allies from making use of them. Thus, during the war, the charts available to the Allies were very soon obsolete; no others were obtainable. Navigation off the Flanders coast, for Allied vessels of any size, therefore, became decidedly hazardous.
The tides on the coasts, in addition to running alternately eastward and westward with considerable velocity, also caused large differences in sea-level amounting to fifteen feet between the highest and lowest states of the tide.
The Canal System
Mention has already been made that the only harbours on the coast eastward of Nieuport were situated at Ostende, Blankenberghe, and Zeebrugge. But these were not natural harbours. They had been artificially cut out of the coast-line by means of dredging. The entrance channels were preserved by piers built out into the sea and by dredging operations designed to retain the desired depths of water.
BIRD'S-EYE VIEW OF CANALS
Ostende, before the war, had been much used as a commercial harbour, and was therefore provided with numerous wharves, basins, and docks. It was a suitable harbour for all classes of submarines and torpedo craft. Blankenberghe was a little harbour about nine miles east of Ostende and three miles west of Zeebrugge. Its depth was exceedingly small; it could, therefore, only be used for shallow draught vessels such as fishing boats, motor boats, and the like. It was true that the rise of tide, amounting to approximately fifteen feet, would enable larger vessels to enter or leave near the time of high water, but any naval vessel stationed in a harbour from which it can only proceed to sea during a limited portion of the twenty-four hours at once loses much of its value. Zeebrugge could accommodate vessels up to a considerable size: the harbour works and depths will be described in detail presently. Although these three places provided the only harbours on the coast, there was a harbour of great importance at Bruges, about eight miles inland from Zeebrugge.
Bruges harbour was also entirely artificial, consisting of locks, basins, and waterways built on the canal system. Bruges was connected to the sea by means of canals running to Zeebrugge and Ostende, these canals converging on the waterways of Bruges in such a manner that vessels of a certain limited size could pass from Ostende to Zeebrugge, and vice versa, without actually proceeding into the open sea. A series of small canals also connected Bruges to Antwerp, via Ghent, but this canal system, being only constructed to accommodate barges, did not materially add to the value of Bruges as a harbour for sea-going vessels.
Of the three canal systems connecting at Bruges, the canal to Zeebrugge easily held first place in importance. This canal was built by the Belgians. It was commenced in 1896 and completed in 1907. Six and a quarter miles in length, it was almost entirely straight throughout. It could accommodate torpedo-boat destroyers or submarines, both of the largest size, and could, if required, have been used by light cruisers.
The Harbours in Flanders
At the seaward end of the Ostende and Zeebrugge canals, locks were constructed so that vessels could pass from the canals to the sea, or the reverse, at any state of the tide, without lowering the level of the water in the canal.
The above-mentioned harbours were used for naval purposes by Germany as follows. Bruges was chosen as the main naval base. Shelters for protecting submarines from aerial attack, floating docks, repair workshops, all the other facilities which go to make a modern dockyard for small vessels, and the necessary stores and ammunition, were to be found there. The number of naval craft based on Flanders appeared to vary considerably; but, at the beginning of 1918, approximately eighteen submarines and twenty-five destroyers or torpedo-boats would be at Bruges on an average day. The submarines lay in the special shelters which were covered by roofs of reënforced concrete several feet in thickness. Bruges, then, was not only the dockyard but also the resting-place of practically all the German naval craft based on Flanders.
The sea exits from Bruges, as already mentioned, were situated at Ostende and Zeebrugge. There was some doubt, however, whether the Bruges-Ostende canal could be used for the passage of anything larger than very shallow draught vessels such as motor boats or barges. The Ostende canal was known to be narrow, tortuous, and shallow; it had been constructed many years earlier than the Zeebrugge canal.
At Zeebrugge and Ostende a few German craft were usually stationed for duties of an immediate nature such as mine-sweeping, patrolling, and duties connected with the defence of the coast. These harbours were specially useful as taking-off places for vessels which had concentrated in readiness for operations at sea, or as bolt-holes for the same craft when pursued by our patrol vessels. Both harbours were open to bombardment from the sea; that reason, more than any other, probably influenced the Germans to use Bruges for their main base. Ostende, being more open to attack from the sea and air than was Zeebrugge, was the less important harbour of the two.
Blankenberghe harbour, owing to its small size and shallow depth, was used as a base for the German armed motor boats; it is believed that about thirty were stationed there. This harbour, being unconnected with the canal system, was not in direct inland communication with Bruges by water.
In addition to the submarines and torpedo craft already mentioned, the Germans had a large number of trawlers based on the various harbours for mine-sweeping and patrol duties. At Zeebrugge they had their largest seaplane base in Flanders; another seaplane base was situated at Ostende.
In due course Flanders had become a veritable hornet's nest. Let us consider for a few moments to what extent these hornets could trouble us.
Our Lines of Communication
Across the English Channel, and especially in its eastern portion, we had established lines of communication of tremendous importance. It is no exaggeration to state that, every few minutes of the day and night, a vessel, of one sort or another, left the English shore for France with her cargo of personnel, guns, ammunition, food or fuel, etc. Day after day, night after night, for months on end, a constant stream of vessels poured across the Channel in support of the Allied armies or on the return trip to English ports with wounded, men to whom a welcome spell of leave had been granted, empties for refilling, motor transport vehicles for repair, and the like. The wounded were carried in hospital ships; but, as the world knows and can never forget, the Germans ruthlessly torpedoed them whenever the chance offered, regardless of the Geneva Convention, heedless of the damnable inhumanity of the proceeding, seeking only for opportunities for indulging in the frightfulness which formed part of their Kultur.
All these vessels were continually open to attack, not only from submarines but also from the surface craft and aircraft based in Flanders. At any chosen moment, preferably at night or during misty days, these hornets could emanate from Ostende or Zeebrugge on their deadly missions. Further westward our trans-Atlantic lines of communication offered innumerable opportunities for the German submarine commanders to display their brutality against comparatively defenceless merchant vessels, or to attack transports carrying munitions of war and troops from the American Continent. The passage through the English Channel afforded the most direct route for German submarines proceeding to, or returning from, their hunting-grounds.
The mercantile traffic off the southeast coast of England and in the entrance to the Thames was also within easy reach of the German bases in Flanders; so were our seaside resorts, such as Ramsgate and Margate, which provided favourable opportunities for bombardments with resultant casualty lists of innocent women and children.
Dunkerque and Calais on the French coast were the nearest seaport objectives to the Flanders coast; they both experienced frequent aerial attacks and an occasional bombardment from the sea.
As a counter to the German craft in Flanders the British Admiralty had established a force known as the "Dover Patrol." As the name implies, this force was primarily based on Dover. Their duties were mainly those of protecting the transports bound across the English Channel, preventing the German naval craft from passing through the Straits of Dover, and watching the exits from Bruges so as to obtain timely information of concentrated German forces putting to sea. The story of the Dover Patrol is of intense interest, but so many pages would be required to do it even bare justice that I can only refer the reader to books written especially on that subject. Suffice it to say here that, day and night, winter and summer, fair weather and foul, the Dover force patrolled the sea so successfully that the German attempts to use their surface craft for attacking the Allies were few and far between. The difficulties of preventing the submarines passing through the Straits of Dover were immense. We must realise that the maximum portion of a submerged submarine visible above water amounts to a periscope of a few inches in diameter. Compare that dimension to the width of the Strait which at its narrowest part is twenty miles. A few inches in twenty miles—if I have calculated aright that means that the visible portion of the submarine would cover little more than one-millionth part of the surface between Dover and Cape Grisnez. And when we also realise that the periscope would only be raised above water for a few seconds at long intervals we shall begin to understand the difficulty of the problem. Yet, as we know now, the Dover Patrol force, under the direction of Vice-Admiral Sir Roger Keyes, eventually rendered the passage through the Straits to all intents and purposes impossible for a submarine. All honour to the Dover Patrol!
The Dover Patrol
A point which, until recently, unaccountably seemed to have escaped notice was that the work of the Dover Patrol was carried out on behalf of all the Allies and of the United States. It was not a British force acting solely in British interests. Though it is difficult, and perhaps invidious, to apportion the credit for protecting the Allied lines of communication, yet there is no shadow of doubt that the troops from Canada and from the United States of America owed to the Dover Patrol force a tremendous debt of gratitude for their safe passage overseas. Recognition of this fact has since been shown by the erection at New York, and on the French coast, of memorials to the Dover Patrol. When the late war has faded into history, and those of us who took part have long since "gone west," such memorials will remain to bear witness to the splendid sacrifice and unselfish gallantry of those hardy seamen who did their utmost to uphold the honour of civilisation and to destroy the forces working for its overthrow. (This opportunity of acknowledging the success of their extremely arduous efforts, humble and brief though the acknowledgment may be, partially counterbalances my regrets at not having had the chance of serving with the "Dover Patrol" except on the occasion which this book is designed to describe.)
CAPTAIN ALFRED F. B. CARPENTER, V.C., R.N.
The final closing of the Straits, however, was far from accomplished by the spring of 1918. At that time we had reason to believe that a large percentage of the total Allied losses in merchant ships was caused by the Flanders submarines, and that the percentage was on the increase.
Now patrol work of the type described above is essentially defensive in its nature. This statement is not intended to imply that the Dover Patrol force were always employed on defensive tactics; such was by no means the case. Our monitors frequently bombarded the coast defences and the harbour works at Ostende and Zeebrugge; our motor boats were continually patrolling close off the three coast harbours, watching for opportunities to torpedo any German vessels which ventured to sea; our mine-laying craft were employed, night after night, in laying mines to the detriment of the German submarines. But from time to time various suggestions had been made that we should adopt still more offensive measures against the enemy. It is a very simple matter to make suggestions, but by no means so simple to accompany them with a reasoned statement, based on logical deduction, which will convince the authorities of their value. Until a particular Plan has been put into execution it may, in the literal sense, be rightly designated a "paper scheme." It is both unreasonable and unfair to attach a derogatory sense to the term. It is equally unreasonable for authors of schemes which have not passed the paper stage to belittle operations when the latter, based on schemes which differed from their own, have actually taken place with successful results.
Paper Schemes
Whatever suggestions were made, it is clear that there could be only two radical methods of attaining our object. The most satisfactory, of course, would have been the recapture of the Flanders coast and of Bruges, with all the hornets in their nests, by means of military operations. Unfortunately that was impracticable; the Allied armies were not yet sufficiently strong. The only alternative to capture of the craft in their harbours was that of preventing them putting to sea—i.e., destroying or blocking their exits. Several schemes for blocking operations had been proposed. In tactical method they had varied from blowing up the harbour entrances, as suggested by the Halifax disaster, to "building in" the entrances under cover of poison gas. Whether such methods were considered too risky, too expensive, or too hopelessly fantastic is more than the author of this book knows.
An attack on Zeebrugge had been strongly advocated by an eminent flag officer in November, 1916, but no details were given by him as to the nature of the operation. In May, 1917, detailed proposals for an attack had been submitted to the Admiralty by another distinguished officer. This attack involved a landing on the Mole at Zeebrugge, the general idea of which was not dissimilar from that eventually followed. This particular scheme had not earned the approval of Their Lordships, nor was it considered suitable by the Vice-Admiral then in command at Dover.
Many months after the blocking of Zeebrugge had become an accomplished fact two earlier schemes came to light—these having emanated from the author of that submitted in May, 1917. In November, 1917, however, the only previous proposals which were available for consideration by the Planning Division of the Staff were those of November, 1916, and May, 1917, mentioned above.
In November, 1917, Admiral Sir John Jellicoe was First Sea Lord and Chief of the Naval Staff. He had requested the Director of Plans to consider, amongst many other things, the possibility of blocking the Belgian ports.
The Plan was evolved in the Admiralty, being commenced on November 13th, and laid before Their Lordships on December 3d. The Plan was accepted as feasible, and earned Their Lordships' decision to have it carried out. No previous Plan had reached that stage. The original edition of the Plan did not emanate from another country, or from civilian sources, or from any other source outside the Admiralty buildings in Whitehall except in so far as the details of one particular phase of the operation were the outcome of conversations, at the headquarters of the Air Force, with an expert on the formation of artificial fogs.
The Conception of the Plan
The foregoing definite fact has been purposely inserted to correct other statements which have been published elsewhere, presumably in error. I shall deal with the details of the Plan in a subsequent chapter.
Before leaving the consideration of the origin of the Plan, I should like to emphasise one particular point. Perhaps this can be most readily illustrated by a simple simile. An uncorked bottle, containing some noxious fluid, stands upon the table. You realise the disagreeable results which will follow on the escape of its contents. You cork the bottle. Now your action is so obviously correct that you scarcely give it another thought. If any credit was due to anybody you would probably take it to yourself; you would not apportion any particular merit to that fond parent who first initiated you into this obvious solution of the problem. In the case, therefore, of the Blocking of Zeebrugge one need not apportion credit to the person who first suggested the mere idea; the credit is entirely due to the man who, in spite of all the difficulties, evolved a method of "corking the bottle" and who, later, overcoming the great obstacles in the way, carried the method into execution.
Before we pass on to review the difficulties of blocking the exits from the German bases it would be advisable to consider the probable effects of such an operation; this being the logical sequence actually followed before the details of the Plan were formulated.
The results to be attained by blocking the exits would probably be as follows. Firstly, there would be a reduction in the number of Allied vessels sunk by mine or submarine warfare; secondly, a decrease in raid activity on the part of the enemy torpedo craft; thirdly, the loss of a convenient advanced base for small craft operating in conjunction with certain movements of the High Seas Fleet; and, fourthly, the reduction in the number of enemy vessels available for the purposes mentioned.
The first two results concerned reduction of enemy activity arising from the longer passages involved by the use of more distant bases such as Heligoland or the German rivers from which the small craft could continue their depredations. The third result speaks for itself. With regard to the fourth, it has already been stated that, on an average day, there would be many torpedo craft or submarines resting and repairing at Bruges. If the exits were blocked the use of these craft would be denied to the enemy, just as effectually as if they were sunk, for as long as the exits remained unopened. This loss to the enemy, temporary or permanent, could doubtless be described in terms of reduction of Allied losses of merchant tonnage. The Admiralty authorities could probably have calculated, within fairly correct estimates, the average loss of merchant tonnage caused to the Allies by a single enemy submarine or surface torpedo craft. Our former average loss per given period would thus be lessened in proportion to the number of enemy vessels bottled up in the canals during that period.
Results to be Obtained
There would, of course, be other, less important, consequences arising from the blocking of these exits; e.g., the inconveniences caused by the necessary transfer of fuelling and repair facilities elsewhere, the extra work thrown on the escorting vessels in the Bight, and the fact that the craft already at sea and operating from the Flanders coast would be forced to curtail their current trips if they desired to arrive at their new bases with their usual reserves of fuel.
All these material gains to the Allies would be of considerable importance, but the moral effect was not unworthy of consideration. The more audacious an undertaking against an enemy the more intense will be the victor's enthusiasm consequent on success, and the greater the despondency and loss of moral to the vanquished. Attempts to block a hostile port in the face of carefully prepared defence measures may certainly be described as audacious, unless the word "impertinent," which the author is inclined to allocate to this particular event, is deemed to be more truly descriptive. If we endeavour to imagine what our own feelings would be on hearing that enemy vessels had entered one of our strongly defended harbours and blocked the entrance, we shall arrive at some idea as to the probable moral effect produced by such an enterprise. In spite of the almost entire absence of activity on the part of the High Seas Fleet, the Germans had never ceased to sing its praises with all the bombast of which their waning spirit was capable. It was not difficult, therefore, to estimate the dejection and consternation that would spread throughout Germany when the success of our efforts became known. The loss of prestige in the German Navy would be not merely certain but perhaps of vital consequence later on.
CHAPTER II
THE LOCAL SITUATION. THE LOCAL DEFENCES.
Zeebrugge Mole
The village of Zeebrugge stands near the entrance to the Zeebrugge-Bruges canal. At about half a mile inland from the coast at Zeebrugge the canal lock was situated. To seaward of the lock, the entrance channel, being open to the sea, was tidal. On the eastern side of the entrance channel, about midway between the lock and the coast-line, a small tidal harbour had been constructed for the use of fishing craft. This tidal harbour was of no special value for naval purposes, owing to its small depth. From the coast-line the entrance channel was continued into the sea for a distance of about two hundred and seventy yards by means of estacades—i.e., wooden piers. These piers, curving outwards from the shore, are conspicuous in the illustrations. For the purpose of protecting the canal entrance from rough seas, which might interfere with the passage of vessels to and from the canal, the famous Zeebrugge Mole had been constructed for the Belgians. Semi-circular in shape, it emanated from the shore at a distance of about half a mile to the westward of the canal entrance; thence it curved round to the northward and eastward. This curved Mole protected a roadstead, of some three hundred acres in extent, from northerly and westerly gales. Easterly winds did not cause such heavy seas as those from the directions already named owing to the protection afforded by the Netherlands coast.
PORT OF ZEEBRUGGE
The construction of the Mole was a colossal task. There are no similar works of such magnitude in Great Britain or the United States. When lecturing in the latter country I always made a point of emphasising that fact to our American cousins; their unfailing humour never failed to appreciate this little friendly "dig."
The total length of the Mole was over one and a half miles. For purposes of description it may be divided into four portions. Commencing at the shoreward end, the first portion of the Mole took the form of a stone railway pier built into the sea for a distance of two hundred and fifty yards. This pier was connected to the second portion, which consisted of an iron-piled railway viaduct three hundred and thirty yards in length. This, in turn, was connected to the third portion, which formed the Mole proper. The latter was built of concrete blocks on its seaward and shore sides, the central part being filled with gravel and paved with granite. The width of this portion of the Mole was no less than eighty-one yards, and its length about eighteen hundred and seventy-five, or rather over a land mile. At its northeastern end, the fourth portion consisted of an extension piece, two hundred and sixty yards long and fifteen feet broad, with a lighthouse at its eastern extremity.
If the Mole had been constructed solid throughout its entire length, the task of keeping the channel, leading to the canal entrance, or the roadstead, at a convenient depth would have been impossible owing to silt.
Silt may be defined as the movement of sand or mud, according to the nature of the sea bottom in the locality, due to current. The bottom of the sea in this locality was sand. The current off the Flanders coast is caused by tide—it is usually spoken of as tidal stream. Tidal streams reverse their direction of movement about every six hours. Now the movement of sand caused by a tidal stream tends to deposit that sand in or against any irregularity with which it meets, whether the latter is a groove on the sea bed or an obstacle such as a wreck. This deposit first takes place from one direction, and then, when the tidal stream reverses, from the opposite direction. It will therefore be seen that, where a channel is artificially cut on the floor of the sea, silt will continually tend to fill that channel again until the bottom is level once more. And a ship which grounds in a locality affected by silt will have sand deposited against her sides much to the detriment of salvage operations. These facts are well enough known to seamen and have an important bearing on this narrative.
Concerning Silt
Suppose for a moment that the entire Mole had been built in solid formation—i.e., that the tidal stream had no free passage under the viaduct. The west-going stream would tend to carry sand into the roadstead between the Mole and the canal entrance, whereas the east-going stream would be unable to remove the deposit a few hours later. Thus the roadstead would soon have become useless, and access to the canal would have been impracticable.
The sand along the whole Flanders coast was extremely susceptible to movement. Such tendency was partially countered by the extensive use of groynes. These latter, however, could not be carried very far out into the sea owing to the difficulties of construction and repair. There were, therefore, no artificial barriers to prevent the movement of the sand to the eastward or westward beyond a short distance from the shore. Hence the necessity for keeping a portion of the Mole open to allow the tidal stream to flow in both directions. Even so, a large shoal had formed in the roadstead, and reduced the acreage available for anchorage purposes.
When first designed the open viaduct was of shorter length than that eventually constructed; the alteration was considered necessary after local experience of the silt had been obtained. The iron piles, or pillars, on which the viaduct was supported were of great strength and much interlaced with steel rods to allow for severe buffeting in heavy gales and to take the strain of railway traffic. A portion was actually demolished by a gale when under construction, and the completion of the Mole was consequently delayed for many months.
When making enquiries in search of expert advice on questions of salvage, I had an interesting conversation with an individual who had had considerable experience in salving vessels in other waters. Maybe this book will remind him of our discussion. In his opinion salvage work presented no great difficulties. It was only a matter of obtaining the necessary apparatus, he thought, and any vessel—concrete-filled or otherwise—could be removed in a month or so. "How about silt?" I asked.
"Oh, silt shouldn't make much difference," he replied, and added, "but we have no silt to speak of in that part of the world, so I cannot say for certain."
We then discussed the possibilities of salving a blockship at Zeebrugge, for he had been informed of the proposed operation. Eventually our conversation nearly resulted in a wager; that we came to no terms was perhaps due to the fact that payment might have necessitated application to a war widow.
The first and second portions of the Mole had not been materially altered by the Germans during their occupation.
The Outer Wall and the Parapet
The third portion of the Mole will require detailed description. In peace days the Mole had been used as a commercial wharf as well as a breakwater. Ships used to secure alongside its inner wall. All the necessary facilities, such as bollards for securing hawsers, fixed and travelling cranes for loading or unloading cargo, and arrangements for embarking passengers, had been provided. A large railway passenger station, nearly two hundred yards long, was situated near its southwestern end; a goods station and a coal shed, both very large buildings, stood further to the northeastward. The floor level of this portion of the Mole was about nine feet above the level of high tide. On the outer (seaward) side a high wall, of great strength and thickness, had been constructed for the purpose of preventing rough seas from breaking over the Mole and damaging the sheds or washing away the railway. The top of this wall was twenty feet above the floor level of the Mole and therefore twenty-nine feet above the level of high tide: at low tide it towered forty-four feet above the sea.
The fourth portion of the Mole was really formed by a continuation of the outer wall, which extended beyond the third portion to the lighthouse.
The appearance of all portions of the outer wall, as viewed by anybody situated in a boat alongside it, was exactly similar throughout its entire length from the lighthouse to the railway viaduct. Thus the individual in the boat, except in the unlikely event of being able to see over the top of the wall, would be unable to tell, at all definitely, whereabouts his boat was situated relative to objects on the Mole. But this fact had not been accidentally overlooked by the designer of the Mole; there was no object in taking it into consideration, for there was then no idea of any vessel berthing alongside the outer wall. For instance, there were no bollards, no cranes, no capstans for working hawsers, in fact no arrangements whatever for berthing a ship. I have already stated that this outer wall was of great thickness, varying from twenty-five feet on the sea bottom to ten feet in that portion standing above the floor level of the Mole. Four feet below the top of the wall there was a pathway, nine feet broad, running the whole length of the wall. This pathway was known as the parapet. The parapet was bounded on its seaward side by the four-foot wall just mentioned; on its inner side iron railings, three feet high, were placed to prevent anybody falling from the pathway to the floor of the Mole sixteen feet below. Flights of steps led up from the Mole floor to the parapet, but these flights were very few and far between.
That portion of the outer wall which formed the lighthouse extension of the Mole was broadened, above the sea level, to about seventeen feet throughout its length. The pathway was similar to that just described, but fifteen feet in width. This portion of the Mole was hollow, a tunnel inside it running from the third portion of the Mole to the base of the lighthouse.
The navigable channel from the open sea to the canal entrance could only be maintained in an efficient state by means of continual dredging, owing to the silt. The channel passed close to the lighthouse at the end of the Mole, and then in a fairly direct line, for a distance of three-quarters of a mile, to a position midway between the extremities of the two piers marking the canal entrance. Thence the deep water channel passed slightly to the westward of the central line between the piers. This latter portion of the channel had become exceedingly narrow by virtue of the sandbanks which had formed on either side of it and which actually uncovered at low water. A vessel drawing more than twelve feet or so was forced to keep exactly in the middle of this dredged channel to avoid grounding. Photographs taken at or near high tide gave the channel the appearance of extending from one pier to the other, at least a distance of one hundred yards; those taken near low water showed how narrow the channel really was. In the region of the two piers the silting of the sand was more rapid than elsewhere: the narrowest part of the channel was situated near the shore ends of these piers.
Defences on the Mole
The Germans had not rested satisfied with either the Mole, the canal entrance, or the lock as they found them. The Mole itself had been transformed into a fortress, and further defences had been constructed for the purpose of guarding the canal.
A PORTION OF THE GERMAN BATTERY ON THE LIGHTHOUSE EXTENSION OF THE MOLE.
VIEW OF THE CANAL ENTRANCE WITH ITS CURVED PIERS.
This photograph was taken at high tide. Note the Mole in the distance
Batteries were placed on both sides of the canal entrance. These ranged from four-inch guns to twelve-inch guns. Barbed wire entanglements were erected along the shore line; trenches, containing machine guns, were dug close behind them. It was believed that a boom of some sort, capable of being hauled across the channel or removed at will, was kept handy to the outer lock gate. The gate itself, "caisson" is the correct technical term, was withdrawn into an armoured housing, impervious to shells or bombs, when the lock was opened to allow vessels to pass through. The caisson was also provided with an armoured roof for defence against aerial bombs. The lights on the wooden piers were only lit when specially required to guide a German vessel to the entrance.
On the Mole a very large seaplane base was established with the original passenger station as its principal building. Several other buildings for housing seaplanes, fuel, or bombs, and workshops were erected by the Germans close by. A merchant steamer, the Brussels, formerly commanded by the ill-fated Captain Fryatt, whom the Germans did to death so abominably, was moored alongside the station, and was believed to be used as living quarters for the personnel of the seaplane base.
The broad portion of the Mole was used as a base for submarines passing through Zeebrugge en route for Bruges or to the open sea; it was also used for such torpedo craft and mine-sweepers as were required for immediate duty in that locality. From the north-eastern large shed to the lighthouse the Mole had been turned into a veritable fortress. It was believed that the lighthouse was used as the Mole signal station. A battery of six or seven guns was situated on the lighthouse extension of the Mole. These guns were at first surmised to be 3.5-inch guns, but it is probable that they were larger—in fact, up to 5.9-inch guns firing a shell of approximately one hundred pounds in weight. It was believed that the guns of this battery could fire out to sea and could be turned to fire towards the shore.
Any vessel approaching from seaward and passing into the dredged channel, en route to the canal, would be within the danger zone of this battery, from the latter's extreme range out at sea to the canal lock, always provided that the state of the visibility allowed the vessel to be seen. Incidentally, owing to the situation of the deep channel, the vessel would be obliged to pass within a few yards of this battery when rounding the Mole end. A vessel endeavouring to berth alongside the outer wall would have to approach close to this battery, i.e., on a westerly course. At first sight it might appear feasible to approach from the westward on an easterly course and thus avoid passing close to the battery, but that is not so. High tide and slack stream do not coincide on this coast. For about three hours on each side of high tide the streams run to the eastward: at other states of the tide there would be insufficient depths of water for a vessel to berth alongside. It would therefore be necessary to approach from the eastward, i.e., to stem the tidal stream.
AERIAL PHOTOGRAPH OF THE CANAL ENTRANCE.
Taken shortly before the enterprise, showing the sandbanks narrowing the entrance channel. At the top of the photograph a dredger at work indicates the position of the approach channel
Now let us imagine for a few moments a duel between this battery and a warship within—say—one thousand yards. The reader probably knows that such a distance nowadays comes within the definition of "point-blank range"; i.e., a range at which a gun practically cannot miss a ship. Picture, then, an average-sized vessel of three hundred feet in length. The guns could hardly miss her—in fact, the gunners could select which particular portion of her should serve as their target. The ship's guns would return the fire. The most vulnerable portions of the battery ashore are the guns themselves. The muzzle of each gun showing just above the wall would, as viewed from the ship, cover barely one square foot in size. Now at golf we call it a "fluke" when a golfer holes out from the tee although he has attained his object. (I apologise for this to non-golfers.) Similarly, if the ship's gun hits the shore gun we should call it a "fluke," although that is the object forming the target. And, as already implied, if the shore gun misses the ship, that also will be a "fluke." On the face of it, it certainly does not look as if the ship would stand much chance, even at a distance of one thousand yards. But how if she is closer? If a thousand yards is point-blank range, how shall we designate a hundred yards?
At the eastern end of the broad part of the Mole, and on its floor level, the Germans had erected a battery of three heavy guns. These were so placed that they could fire on any incoming vessel immediately she rounded the lighthouse. Woe betide a vessel attempting to do so in the face of such guns. The latter were probably of the 5.9-inch type. Under water, immediately below this battery, we eventually found some submerged torpedo tubes, but I am not aware as to whether they were constructed before the blocking operation or not; their direction of fire was similar to that of the guns above them.
Close westward of these batteries of heavy guns and torpedoes, and standing against the high outer wall, the Germans had constructed a long shed of reënforced concrete; this shed provided the living space for the personnel of the Mole garrison.
The total numbers of Germans on the Mole probably reached not less than a thousand. Although this number may include the personnel of the seaplane base yet they would all be available for the defence of the Mole in case of an attack.
Slightly to the westward of the garrison's quarters, trenches had been sunk in the floor of the Mole and surrounded by three complete sets of barbed wire entanglements. It was believed that the usual accessories of a coast fort—e.g., searchlights and range-finders, etc.—were placed on the outer wall parapet, and that there would probably be some small guns there also.
The Booms and Torpedo Craft
So much for the Mole itself. Across the channel the Germans had placed booms. One of these, consisting of four Rhine barges, was moored between the eastern end of the broad part of the Mole and a buoy situated two hundred and seventy yards to the southward. These barges were filled with stone, had nets slung beneath them, and were connected together by wire hawsers. If a surface vessel attempted to pass between the buoy and the Mole she would be brought up by this boom and probably damaged by collision with one of the barges. If a submarine attempted to dive underneath the barges she would be caught up in the nets. The other boom consisted of entanglement nets moored between a series of buoys to the southeastward of the barges. Any ship attempting to pass through them would probably have her propellers entangled, with the result that her engines would be brought to a complete stop. Thus, whichever boom was encountered by a ship, the latter would, at the least, be partially disabled and stopped. The Mole batteries could then have sunk her at their leisure by gunfire. The only route by which a vessel could pass clear of these two booms was that between the southeastern barge and the northern entanglement net; i.e., within two hundred and fifty yards of the heavy gun battery on the Mole. But even if, by dint of good fortune or special good management, a vessel managed to pass the Mole batteries and the booms, she would still have to run the gantlet of the naval vessels in the anchorage and the batteries on shore before reaching the canal.
THE NORTHEASTERN END OF THE MOLE
a. The shadows of the parapet wall and of the lighthouse at its extremity
b. The Mole batteries
c. Trench system surrounded by barbed wire
d. German torpedo craft alongside Mole
e. The barge boom
f. The boom of entanglement nets
The German torpedo craft, which were available for local duty, used to berth alongside the inner side of the Mole, close to the westward of the barge boom. By virtue of their guns, torpedoes, and searchlights, and the fact that they probably kept up steam in readiness for instant action, these craft provided a valuable addition to the Mole and canal defences.
The foregoing description of the local defences at Zeebrugge has probably been sufficiently detailed to lead to the conclusion that the Germans were fully alive to the possibility of attacks on the Mole or canal. Whether or not they considered that such attacks would only form part of some more ambitious operation, such as a military landing on the coast, our enemies had left practically no stone unturned to repel them. The defence measures must have appeared, especially to those on the spot, to be more than sufficient.
It is well known that, although the possession of detailed local knowledge will usually be of great value towards the formation of plans of attack, there are occasions when local knowledge is apt to make local difficulties loom extremely large. For instance, in this particular case, the navigational difficulties caused by the strong tidal stream, the difficulty of recognising objects on the low-lying shore during darkness, the uninviting appearance of the outer Mole wall as an obstacle to be surmounted, and many other matters would probably have induced the belief, in those who were actually acquainted with these difficulties, that such attacks would have no chance of success. There is, therefore, reason to believe that, although they realised an attack might be attempted, the Germans were perfectly satisfied that the defences could neither be improved nor penetrated.
The reader will probably have arrived at the conclusion that the Germans were devilish in their thoroughness. Yet there was still one joint left in their armour—and we penetrated it. But I must not anticipate.
CHAPTER III
THE OUTLYING OBSTACLES. CONSIDERATIONS OF SALVAGE.
Thus far I have only dealt with the local defences of Zeebrugge. But there were many other obstacles in our way—such as the coast batteries, mines, surface patrol vessels, submarines, aircraft, and the vagaries of the weather in addition to the navigational difficulties mentioned in the first chapter.
The coast-line of Flanders bristled with guns. The section of the coast from three miles west of Ostende to six miles east of Zeebrugge, approximately twenty-one miles in length, was defended by two hundred and twenty-five guns; one hundred and thirty-six of these were of the heavy type, i.e., six-inch and above, up to fifteen-inch guns.
At one period of the war, soon after the Germans first obtained possession of that locality, the coast defences had been few and far between. In those days our ships used to bombard from such short ranges as ten thousand yards. In course of time heavier guns were set up on shore so that our vessels were forced to keep at a more respectful distance. The first bombardments from ten thousand yards had been answered by the establishment of German guns having a range of fifteen thousand yards. When better weapons became available for bombardment from twenty thousand yards the Germans replied with guns firing up to twenty-five thousand yards. And thus the duel continued. Finally, the ranges increased to upwards of forty thousand yards (twenty-three land miles). Monitors were specially constructed for this purpose and their marksmanship was wonderfully accurate. This accuracy is borne out by the fact that scarcely any damage was caused to the residential quarter, although Ostende was bombarded again and again; yet works of military importance, such as docks and railway stations, closely adjoining the residential quarter, were hit time after time.
In a straightforward gunnery duel between a ship and a fort, within the effective range of each, the former stands no chance. In these days, however, such duels savour little of the old-time broadside fighting between ships.
Even the largest and most modern coast guns are of comparatively small avail for defensive purposes unless the attacking ships are visible, or unless the firing can be controlled satisfactorily by such indirect means as the use of aircraft for observational purposes. At night the attackers must be illuminated by star-shell, flares, or searchlights. Under the ordinary fog conditions—i.e., when the whole locality is obscured by fog—aircraft cannot observe the results of firing nor can the attacking forces be illuminated.
Under exceptional fog conditions—i.e., when a fog (natural or artificial) lies between the shore guns and the attacking vessels, the latter being in clear weather—good co-operation between the batteries and aircraft in daylight enables the fire to be directed so accurately as to ensure destruction to vessels which remain in the danger zone.
