British minefields were responsible for the only damage of any significance inflicted on the German ships Scharnhorst, Gneisenau and Print Eugen in the course of their dash up the English Channel on February 12, 1942, and Captain S. W. Roskill, RN, in Vol. II of The War at Sea, has presented a characteristically lucid and unbiased account of this episode. The historian, however, must of necessity permit himself some degree of condensation if his work as a whole is to retain its balance, and I believe it to be the duty of those having personal knowledge of a particular aspect of any event of historical interest or importance to place that knowledge on record, for the possible benefit of those who may at some future date wish to study that aspect in more detail.
It is this possibility that is the principal reason for the present writing, which is confined to a consideration of the British minelaying operations conducted with a view to impeding the passage of the German ships. It is, in any event, the sole excuse for the employment, where appropriate, of the first person singular.
The Problem
At the material time, it was my privilege to L be head of that section of the Naval Staff at the Admiralty charged with the planning and general oversight of all British minelaying operations, including (in concert with H.Q. Bomber Command R.A.F.), those carried out by aircraft.
Late one night towards the end of January, 1942, I was sent for by Rear Admiral A. J. Power, Assistant Chief of the Naval Staff for Home Operations, who, after outlining the general strategic position with regard to the German heavy ships at Brest, showed me the draft of an appreciation which he had prepared as to their probable movements. This document, which in its ultimate form is reproduced as an appendix to this article, must surely rank as a classic in the field of applied clairvoyance.
The Admiral then asked me for my proposals as to the possible employment of minefields as an obstacle to the passage of the German ships should they (as he confidently predicted) decide to break up-Channel, and these proposals we discussed at considerable length.
Early the next morning, I was again sent for by Admiral Power, who informed me that the First Sea Lord, Admiral of the Fleet Sir Dudley Pound, had approved his appreciation in principle, and that I was to go ahead with the minelaying plans without waiting for its final acceptance and promulgation.
The Considerations Involved
Before describing our plans in detail, it may perhaps be of interest to note the following points:
(a) For many months, we had been laying mines in the known or suspected enemy routes along the French, Belgian, Dutch, and German coasts, and in the opening days of the war a mine barrage had been laid across the Straits of Dover. These operations, however, formed an integral part of the over-all strategic concept in Northern European waters, whereas those about to be described were more of a tactical nature; that is to say, they were designed to deal with a specific target that was expected to follow a comparatively circumscribed route within a relatively short period of time.
(b) It was (and remains) a cardinal principle of minelaying warfare as conducted by the British: first, that a minefield cannot be expected to present an impenetrable barrier to a determined enemy, and second, that tactical minelaying must always be regarded as an adjunct to the operations of mobile forces, and not as a complete substitute therefor.
(c) It requires a minimum of two people to engage in armed conflict, and one of them must, by definition, be on the other side. In other words, the enemy has a say in the matter, and in this particular instance he was not only (we assumed) fully alive to the potential mine menace, but he was extremely well placed to meet it, i.e., he could (apart from certain limitations of a purely physical nature) choose the safest route and then subject that route to the most intensive minesweeping prior to emerging from Brest on a date and at a time selected by him.
With these general considerations in view, the question to be answered was: “What kind of mines shall we lay, where shall we lay them, and how shall we lay them?” To some extent, of course, the question answered itself, but none the less its component parts merited careful study if their true interrelation was to be appreciated.
As already implied, we had a fairly reliable working knowledge of the routes normally followed by enemy traffic between Brest and the River Elbe, but here we were faced by an abnormal situation. We therefore asked the staff of the Director of Minesweeping to imagine that they were temporarily on the staff of the German Admiral, and to tell us what route they would advise him to follow. That they did a good job was to be proved by subsequent events, and many months later we were happy to be able to return the compliment in connection with the Madagascar operations. On that occasion, the staff of the Minesweeping Division, who had reliable information as to local minelaying resources, asked my staff to forecast how those resources might be employed, and the answer turned out to be just exactly 100% correct. The secret of success, when engaging in this particular type of crystal-gazing, is to assume that your opponent is at least as intelligent as you are yourself, another basic principle that is frequently overlooked by the planner.
The most difficult part of our problem lay in the fact that if we were so fortunate as to place our minefields in the chosen path of the German ships, that would be the very path (as noted above) to be subjected to the most intensive enemy minesweeping. Our only hope of success, therefore, lay in the infliction of a technical defeat on the enemy minesweeping organization, coupled with the possibility that their main units might be deflected from their preselected route and blunder into unswept waters.
In addition, therefore, to the traditional and somewhat obvious use of “mixed bags” of different types of mines (the purpose of which is to render the minesweeper’s task more arduous and dangerous, rather than to defeat him altogether) we went very carefully into the use of “delayed release” moored mines and “delayed arming” ground mines. The normal purpose of these types of mines was to provide automatic replenishment of a mined area, but of course they always stood the chance on a somewhat hit-or-miss basis of rendering waters dangerous shortly after those waters had been swept and declared safe.
Here, however, we were dealing with a specific short-term problem, and so we worked out a scheme designed to have the maximum chance of providing at least one minefield that would elude the enemy minesweepers but would still endanger his main units no matter at what time of day or night they passed through the Channel.
The Minelaying Plan
In the light of all the available information and advice, and having regard to the nature and extent of our minelaying resources, the following plan was evolved:
(a) The fast minelayers Manxman and Welshman (with a speed of 39 knots and a capacity of 160 mines apiece) were to lay a series of minefields composed of a mixture of moored contact and moored magnetic mines, the fields to be disposed partly in the known or suspected enemy routes along the northern coast of France, and partly in the deeper water further to seaward, the mines to be timed to release from their anchors and take up their pre-set depths in accordance with the scheme designed to defeat the enemy minesweepers, and to which reference has already been made.
(b) Aircraft of Bomber Command were to lay ground magnetic mines in an area off Terschelling, one of the more westerly of the Frisian Islands. We had no choice but to use magnetic mines, the acoustic type not yet having come into production, but several clever versions of the magnetic type were available, and could be set to arm at pre-selected times.
This particular area was chosen for a variety of reasons. First, it not only embraced the approaches to the known enemy-swept channels, but it was one through which the enemy ships were almost bound to pass if they were to follow the shortest route home after running the gauntlet of the Channel; secondly, it was, owing to the presence of mines laid in previous operations, only capable of approach by aircraft; and thirdly, the area was so placed as to impose the maximum amount of steaming on any enemy minesweeping forces detailed to investigate it. The principal disadvantage lay in the fact that the water was on the deep side for the employment of ground mines, but this consideration might, we hoped, lead the enemy to regard the area as not worth mining, and therefore as not worth sweeping.
In an earlier plan, drawn up in 1941 with a view to countering a possible sortie of the German ships from Brest, the last-minute laying of aircraft mines ahead of them in the Channel had been envisaged, but had, I am glad to say, subsequently been abandoned on the score of the possible difficulty of having the aircraft available to drop the right kind of mines in the right place at the right time, and also because of the probable embarrassment to the free movement of our own surface forces.
(c) Plover, a small coastal minelayer with a capacity of 100 mines, was to reinforce the central portion of the Dover Barrage with moored magnetic mines. These latter were admirably adapted to take care of one of the more difficult features—from the minelaying point of view—of the Straits of Dover, i.e., the considerable rise and fall of tide. The area chosen was in the deepest water between Dover and Cap Gris Nez, and it was realized that the German ships would be unlikely to bring themselves so far within the range of the heavy shore batteries at Dover merely for the sake of making use of this deeper water, or of giving the gunlayers a little practice. The operations to be carried out by Plover were, in fact, more in the nature of a back stop designed to endanger the enemy should he be forced by some unforeseen circumstance to adopt a course of action which he would not otherwise have adopted (or, in the alternative, should he prove to be less intelligent than we assumed to be the case).
For these reasons, we made no attempt to introduce anything in the way of delayed release mines, etc.— Plover was simply to lay a straightforward minefield in an area that we hoped the enemy would ignore from the minesweeping point of view, but through which he might be forced to pass.
By the end of a strenuous day involving, in addition to the cerebration to which reference has already been made, much telephoning with the staff of the Vice-Admiral, Dover, the Naval Staff Officer at H.Q. Bomber Command, and the Director of Armament Supply, all was in hand. American officers with whom I have discussed this aspect of the matter have on occasion expressed their astonishment that such a thing could be. It must, however, be remembered that we had a comparatively small and very flexible organization, that there is no part of the British Isles much more than sixty miles from the sea, that the operations were to be carried out on our own doorstep, and finally that I had been given a blank check by my superiors to “get on with it and not bother them with details.” There was practically no paperwork involved from start to finish.
In the days which followed, the plan outlined above was implemented. The Manxman and Welshman, with their high speed, were admirably adapted to the clandestine laying of mines off the northern coast of France, and I have recorded elsewhere that they laid fourteen minefields on twelve consecutive nights. In the report of the Board of Inquiry appointed to inquire into these events, however, it is stated that between February 3 and 9 these two ships laid about a thousand mines in six fields between Ushant and Boulogne, and this statement must presumably be based on information provided by myself. The apparent discrepancy is, no doubt, due to the circumstance that the report of the Board was confined to a consideration of the period which began with the issue of the Admiralty appreciation, whereas these ships had in fact already been “running like scalded cats” (to quote a remark made by Admiral Power at the time) for some nights previously.
Aircraft of Bomber Command laid 98 ground magnetic mines in five different groups in the selected area off the Frisian Islands. At first sight, this effort may appear to have been on the low side, but such is by no means the case. First, it must be remembered that the bomber aircraft available at that time could carry only one mine apiece, and secondly that we were acting on the principle that a small number of mines laid with accuracy in the right places can be just as effective as a larger number scattered indiscriminately over an area which may or may not contain the right places.
In order to achieve the desired degree of accuracy, the unusual course was adopted of laying the mines by day, utilizing all possible cloud cover. The aircraft were in a position to make a short run-in from a point of land which could be identified by them with certainty, but at the same time they were screened from observation while actually laying the mines.
Plover completed her part of the operations according to plan, and we sat back to await events.
The Outcome
We had, apparently, been correct in our assumption that the enemy would appreciate the potential mine menace and would in consequence subject his chosen route to the most intensive minesweeping. According to Adolph Galland, in The First and the Last, no less than eighty minesweepers were employed who “found 98 moored and 21 ground mines on the route” and who “detected and removed three mine barriers.” The latter expression presumably refers to the sweeping of complete minefields laid by either the Manxman or the Welshman, but, in any event, it is clear that we had succeeded in placing a reasonable number of mines in the right place. One enemy minesweeper was mined and sunk in the course of these operations.
Before proceeding to deal with the events which occurred on February 12, it is expedient to interpolate here that first blood fell to one of the minefields laid by Plover to reinforce the Dover Barrage. Some time prior to the sortie of the German heavy ships, the destroyer Bruno Heinemann was mined and sunk in this area while on passage down-Channel to augment the enemy forces at Brest. One of the more disappointing features of mine warfare is the difficulty of identifying an enemy casualty with the operations of a particular minelayer, and so it afforded me considerable gratification on this occasion to be able to cause a congratulatory message to be sent to Plover by the Lords Commissioners of the Admiralty.
It was not until 11:25 a.m. on February 12 that news reached the Admiralty of the presence of the German ships in the Channel. They were then approaching Boulogne, and on arrival in the War Room, I was informed that they had just passed through one of my minefields. I had, however, by then become inured to the fact that an unsuccessful minefield always belonged to me, whereas a successful one always belonged to the Admiralty. It just so happened to be one of the occupational hazards of being a mine-planner that I had learned to accept with a nicely calculated blend of dignity and good humor.
With regard to the events preceding this report, Galland states: “The first dramatic note crept into the operation when naval security forces discovered a previously unnoticed minefield off Dieppe only a few hours before the ships were due, and although a channel was swiftly swept by an all-out effort of four minesweepers, the decision to pass through this barely cleared path was a very risky one. But there was no alternative but to return and call the whole operation off." (My italics)
This was undoubtedly one of our delayed release fields, and the episode shows how nearly successful we were in defeating the enemy minesweepers by the use of this stratagem.
At approximately 2:30 P.M. Scharnhorst was mined. In Captain H. J. Reinicke’s account of the affair in the June, 1955 Proceedings, the German ships had just previously been forced to take avoiding action to counter a torpedo attack by British aircraft, and the mining occurred while they were regaining the swept channel. This was an excellent example of the potential value of a minefield in a case where an enemy has an unforeseen course of action imposed upon him.
The interesting point is that the German ships were, at the time, apparently in the latitude of Flushing, and insofar as my memory serves me, no minefields were laid in that area in accordance with the specific plans to which this article has reference. It can therefore only be surmised that the damage was inflicted by a minefield laid by Coastal Force Craft in accordance with routine strategic operations. From the outbreak of the war, however, we had kept meticulous records of the position and composition of all minefields, together with a diary of events, and (provided that the position in which Scharnhorst was mined can be established with any degree of accuracy) the matter could be cleared up by a reference to these documents, to which I do not, of course, have access at the present time.
Later, the German ships encountered the minefields laid by Bomber Command off the Frisian Islands. At 7:55 P.M. the Gneisenau was mined, and at 9:34 p.m. the Scharnhorst was mined for the second time. So once again we had, apparently, succeeded in getting some mines in the right places, even though we had appreciated that the depth of water was probably too great to expect lethal damage to be inflicted by a ground mine.
We did not, of course, know of these casualties at the time, and from the mine warfare enthusiast’s point of view it is sad to reflect that the Scharnhorst, as a result of mine damage, lay helpless in the open sea for two periods which totalled approximately one hour and twenty-five minutes, during the second of which periods her fire-control system was out of action.
In so far as this aspect of the story remains to be told, during the afternoon of February 12, I sought and obtained permission to concert with Bomber Command the laying of a small “forlorn hope” minefield off the mouth of the River Elbe.
This operation, carried out in appalling weather conditions was, however, of no avail; in the early hours of February 13, the Gneisenau and Prinz Eugen entered the River Elbe, and the Scharnhorst limped into Wilhelmshven, the former ship never to put to sea again, and the latter eventually to meet her doom at the hands of British naval forces in northern Norwegian waters.
Post-Mortem
In due course, the “escape” of the German ships was made the subject of a judicial inquiry, and in preparing to give evidence thereat I found myself in something of a quandary. Although mine warfare is in no sense a Black Art, an appreciation of the finer points relating to its conduct was, at the time, confined to a comparatively small body of people. I therefore deemed it advisable to deliver myself of a short homily on the capabilities and the limitations of mining material, and on the essential need for the exercise of “low cunning” in employment of that material, before proceeding to describe in detail just what we had tried to do, and just how we had tried to do it.
The Board of Inquiry, it is agreeable to record, appeared to be well satisfied with this approach, and indeed I was later informed by a mutual acquaintance that the Chairman of the Board, Mr. Justice Bucknill, had been so intrigued by what he described as the “poacher-gamekeeper” aspect of our problem that he could talk of little else.
Summary
The results of the operations herein described supported the theory that although a minefield may be a static weapon to which the enemy must come if he is to be sunk or damaged, it none the less presents a potential menace in cases where it has not only been correctly located, but has also succeeded (either wholly or in part) in evading the activities of the enemy minesweeping forces; and that if these latter conditions are fulfilled, the menace presented is not affected by those considerations which may either hamper or preclude the operations of mobile forces (e.g. bad weather, low visibility, lack of accurate intelligence of enemy movements, delay in or failure of communications, etc.).
The operations, moreover, exemplified the principles enunciated at the beginning of this article to the effect that a minefield cannot be expected to present an impenetrable barrier to a determined enemy, and that tactical minelaying must be regarded as an adjunct to the operations of mobile forces, and not as a substitute therefor. It is ironical to reflect that the very considerations noted above which did not affect the menace presented by the minefields were amongst those which were responsible for the inability of our mobile forces to exploit the damage actually inflicted by those minefields.
Although I have stated my principal reason for placing the foregoing observations on record, I cannot close without paying my personal tribute to those who assisted in the planning of the operations, to those responsible for the design, production, inspection, and supply of the mines, and above all to those officers and men of the Royal Navy and the Royal Air Force who by their skill and daring enabled the minefields to be laid with stealth and accuracy.
Their sole reward must be the knowledge of the successful outcome of their efforts, and the fact that the Board of Inquiry reported as follows:
"Mines. We have no comment to make on the minelaying. The work appears to have been skillfully done both in planning their position and in the actual laying of them by the two services in cooperation”
Appendix
ADMIRALTY APPRECIATION OF FEBRUARY 2, 1942
Possible Departure of the Brest Ships
“The Brest ships cannot be fully efficient yet; although they have led a charmed life the Germans must be anxious to get them away to a safer harbour.
“Only if we can anticipate the plan of their departure can our chances of destroying them be good.
“If we accept the German ships as not being fully efficient at the present time, it is fair to assume that they will evade contact with our forces until they have become efficient.
“On the above assumption, the German ships will try to reach a satisfactory exercising area which may be—
(a) In the ocean spaces. Here the ships would lack many facilities required for practices, whilst fueling would present considerable difficulties.
(b) The Baltic is denied to the Germans by ice conditions at present, whilst in the Bight existing winter conditions are entirely unfavourable for exercising.
(c) The Gulf of Genoa might provide the necessary facilities, whilst Dakar cannot be entirely ruled out.
(d) At Trondjheim the German ships would be secure and able to exercise freely.
“At present there is little evidence to show which way the Brest ships will go if and when they leave Brest.
“The presence of the Tirpitz at Trondjheim may easily be accounted for by the tense situation on the Norwegian coast, ice conditions in the Baltic, and the temptation of our Russian convoys.
“There are three (possibly five) large and five small destroyers at Brest, all of which have recently arrived. Minesweeping operations in the approaches to Brest have recently been seen. There has been no distinctive shape detected in any of the air reconnaissances flown by the Germans in the vicinity of Brest. These are indications of movement, but no indication of its direction.
“With the bad flying weather now prevalent, we must accept the fact that these German ships can leave Brest without our knowledge, and maybe there will be a lapse of 48 hours, or even more, before we discover that Brest is empty.
“At 25 knots, and on likely courses, the enemy could reach:
(a) Denmark Straits in 90 hours.
(b) Gibraltar in 50 hours.
(c) The Iceland-Faeroes Channel in 72 hours.
“These are all long passages, and with reasonable weather we should know that the ships had sailed from Brest before they could arrive at (a), (b) or (c).
“The short cut for the German ships is via the English Channel. It is 240 miles from Brest to Cherbourg, and another 120 miles from Cherbourg to the Dover Straits. Whilst ships could make the passage from Brest to Cherbourg, or from Cherbourg to the Dover Straits, in the same dark period, they could not make the complete passage from Brest to the Dover Straits in one dark period.
“They are aware of our mining activities in the Dover Straits, and they recently lost a destroyer there. It is therefore highly probable that they would time their passage through the Straits for about high water.
“At first sight this passage up the Channel appears hazardous for the Germans. It is probable, however, that, as their heavy ships are not fully efficient, they would prefer such passage, relying for the security on their destroyers and aircraft, which are efficient, and knowing full well that we have no heavy ships with which to oppose them in the Channel. We might well, therefore, find the two battlecruisers and the 8-inch cruiser with five large and five small destroyers, also say twenty fighters constantly overhead (with reinforcements within call), proceeding up Channel.
“Taking all factors into consideration, it appears that the German ships can pass East up the Channel with much less risk than they will incur if they attempt an ocean passage to Norway, and as it is considered the Germans will evade danger until they are fully worked up, the Channel passage appears to be their most probable direction if and when they leave Brest.”