Editor’s Note: The author of this article, Rear Admiral Spindler, was, during the war, on duty in the Ministry of Marine in the section charged with construction and development of submarines.
The new Disarmament Conference proposed by the League of Nations for 1926 will re-open the question raised during the Washington Conference in 1921-22, which was much debated without being solved—namely, the extension of the restriction of naval armaments to the submarine. Again, as in Washington four years ago, debates are to be expected regarding the value or the uselessness of submarines, the inhumanity of their employment against merchant shipping in time of war, and the significance of the submarine weapon otherwise as a factor in naval warfare. In England, whose representatives were the spokesmen against the submarine, public opinion has lately been aroused anew against this weapon since the accident to the M-i; and one may regard the heated and exhaustive discussions in the press and the resolutions and arguments in the Parliament following that disaster as a basis for further debate in favor of disarmament.
The judgments passed on the value of the submarine, as debated by the individual nations, in the forum of the conference of the League of Nations, will be consciously or unconsciously colored by political aims. That nation which regards the existence of the submarine weapon in the hands of its probable enemies as a vital threat, will attempt to prove to the world that the value of this weapon, where otherwise employed than in the inhumane commerce warfare, is highly problematical, and will necessarily advocate the “abolishment of the submarine.”
For this reason the time appears propitious for a strictly unbiased analysis of the question of submarine warfare and the fighting effectiveness of submarines from a purely military and technical standpoint; and nothing can be better chosen as a basis for this discussion than the historical facts and data pertaining to the German submarines during the war.
Only in this war were such large scale and comprehensive measures for attack and defense brought into play, and only in these operations were the full possibilities of the submarine thoroughly demonstrated. Further, the German submarine operations themselves were the fundamental cause of the present-day tendency to condemn the submarine entirely. Also, it should be noted here in advance that the military and technical possibilities of the submarines have not been notably improved beyond the type of German submarines which were last placed in active service. The increase in displacement in the submarine which has occurred in some navies of the world in the post-war period has brought with it nothing radically new. This will be discussed in detail later. Therefore those lessons derived from the German submarine war experience may be applied to the near future practically without exception.
Two explanatory remarks should be inserted in this introduction. In order to concentrate the following discussion on the principal factors under consideration, it will be restricted to a consideration of the principal operating zones of the German submarines: the North Sea and the waters around England. Further, in the interest of brevity, we shall not go into the question of the employment of mines by submarines, since this is not a question which is especially open to dispute.
An explanation is in order regarding the submarine commerce warfare which is discussed in the following paragraphs. After the war there was created an international feeling against any employment of the submarines against merchant shipping, which has lately been revived in England as previously noted, and which first assumed tangible shape in the Washington Conference in 1922. For this reason it might appear questionable whether such submarine activity need even be considered in the future. Opinions have always differed regarding the binding character of international law and treaties where a nation is engaged in a struggle for existence.
In reality, in the history of the past, might has counted for more than right in time of war. In any event it is certain at least that the present state of the treaties does not preclude the unrestricted employment of the submarines in the future. So long as the situation remains as it is, this method of the employment of submarines cannot be dismissed from military consideration.
The submarine warfare against England’s overseas trade occupied the German submarines to a great extent during the entire period of the war and exclusively from the beginning of 1917 on. The discussion of the submarine commerce warfare will therefore follow in logical order in the treatment of the subject. The opportunities for the employment of the German submarines in connection with the purely military operations of the fleet were very restricted so that throughout the whole world, commerce warfare is understood when German submarine warfare is mentioned. In spite of this, however, the purely military operations of the submarines are by far the most interesting to the expert. The second section of this article will be devoted to that subject.
If one attempts to draw conclusions from the German submarine commerce warfare and its effects which shall be applicable to other nations in some future war, it is highly important that two factors should be taken into consideration which were of prime importance in their influence on the German submarine operations: the strategic situation in which the bases of the German submarines stood in relation to their principal enemy, England; and the sources of strength in material and personnel on both sides, particularly those which formed the basis and the reason for the development of the German submarine weapon.
No preparations had been made in the German Navy for the employment of submarines against enemy commerce prior to the outbreak of the war in 1914. The German naval authorities had developed no plan of operations whereby an enemy, England, could be attacked through her overseas commerce and thus become possessed of a weapon which would be really effective in operations against the vital nerve of the island empire. The number of submarines corresponded to the strictly military estimate as one of the numerous auxiliaries in naval warfare, in the sense that the decisive role was assigned to the battleships. Therefore, no preparations were made which had as their purpose an immediate increase in the number of submarines under construction at the outbreak of war by drawing on the industrial strength of the nation. On the other hand, one might say that in 1914 the German Navy possessed a technically highly developed type of submarine which throughout the war was able to meet all the demands of the service. On the part of the enemies of Germany at the outbreak of the war there were lacking practically every means for effectively combatting the submarines. A characteristic example of their helplessness is the sinking of the three English cruisers in September, 1914, by the U-p, without the slightest counter-offensive.
Such were the starting points on both sides. The weakness of the allied naval forces in regard to submarine defense was a point of marked inferiority. The possibility offered the German Navy for a surprise attack by means of a new and already well- developed weapon which they had at hand was not utilized. In the future, such a combination of circumstances will not be encountered.
In the course of the war the German submarine weapon was considerably strengthened by extraordinary exertions. On the whole, 343 new submarines were placed in service in Germany. In order to accomplish this enormous achievement, which could only be carried out by putting the submarine increase above the other interests of the national defense, Germany was favored by the highly developed state of her industry and technique, as well as by the fact that the fundamental material requirement, the raw material, was either in Germany itself or else in those areas open to her, and available to the munitions industries. In the same manner, the German Navy provided a supply of first class personnel necessary for the manning and command of these craft, a requirement which is of greater military importance for such vessels than for any other branch of the naval service. After the development of the anti-submarine measures the war service on board submarines exacted—aside from physical fitness—the highest degree of intelligence of ever)' man in the crew, and further demanded a thorough military, naval and technical training which could not be improvised in a few months during the war. The fact that it was possible to select the supply of the needed personnel for the German submarines (which required in all about 13,000 men, including the highly trained replacement crews) was largely due to the fact that the German fleet served as a means of training a reserve of personnel, from which officers, petty officers and special enlisted ratings could be carefully selected.
In regard to the development of the anti-submarine measures on the part of the enemies of Germany, one fact was in their favor— in fact it was their salvation—that was, the complete discontinuation of the submarine warfare from the summer of 1915 to the beginning of 1917 which gave the allied nations the time to develop and organize their anti-submarine offensive on a large scale after the short flare-up of the submarine warfare 1915 had made them aware of their danger. The different means of submarine defense are known to the naval expert. With regard to the offensive measures, mines and depth charges were by far the most effective. Of the 166 German submarines which were destroyed during the war as a result of the enemy anti-submarine measures; according to fairly exact information, thirty-seven were lost due to mines alone, thirty-three were destroyed by depth charges, while the other anti-submarine measures caused relatively much lower losses. Of the many defensive measures the very excellent development of the English convoy system for merchantmen proved an exceedingly great obstacle for the German submarine. Toward the end of the war the attack on a protected convoy meant the risk of the boat. As the submarine defensive measures were perfected the German submarine losses increased. However, in the struggle between the submarine commanders in the construction of new submarines on the one hand and the anti-submarine measures on the other hand, the Germans were not inferior. The English version that the submarine menace was overcome at the conclusion of the war is not in agreement with the facts of the case. Rather it was possible, even in spite of the increased anti-submarine measures in 1918, to maintain the submarine successes at the high level and to equalize the losses, which averaged about seven boats monthly, by new construction, and supply the necessary crews. With regard to the subject matter of this article there are two principal conclusions to be drawn from the above in this connection: the rivalry between the submarine and the anti-submarine measures with the progress of the war was very intense. In a broad sense, to this should also be added the mine operations against the submarine bases and the mine-sweeping tactics for clearing and keeping open the submarine routes. The more the submarines threaten the enemy’s vital communications and the closer these operations are conducted to the, vicinity of the enemy coast and their patrols, the greater the danger to the submarines; but one cannot deny that in spite of all this, boats which are boldly and expertly handled will still have success. That is one conclusion. The second is the fact that in order to conduct submarine operations on a large scale with the purpose of forcing a decision with this weapon, the entire strength of personnel and material of the combatants will be involved to a very great extent both for attack and defense. More than with any other weapon, this service demands the requisite material replacement, owing to the complicated submarine construction, in order that the losses may be more than equalized by new construction.
The geographical situation of the two opposing powers, Great Britain and Germany, must also be taken into consideration as one of the decisive factors in the effectiveness of the submarine commerce warfare. On the one hand, the nation attacked, England, was dependent on her overseas commerce for the supply of essential foodstuffs. This circumstance led to the assumption that an energetic attack of the submarine might play a decisive role in the war. On the other hand, the attacking state, Germany, found herself in the worst conceivable strategic situation for the conduct of such submarine warfare. The German Bight, located in a small angle of the North Sea with the submarine bases close together, was much easier to blockade with mine fields than a long coast line with scattered harbors. The narrow channel between Dover and Calais and the stretch of water between Norway and Scotland offered further opportunities for blocking the submarine routes with mine fields. Further, the most important war routes for the overseas trade to England lay to the westward of the Island Empire. The routes to the operating zone from the North Sea bases were therefore very time-consuming for the German submarines. Out of the three to four weeks in which a submarine stationed at Helgoland was at sea, about two weeks of this time was consumed in going to and returning from station. The longer the period of the individual undertaking of the submarine, the longer the corresponding overhaul period required by the delicate, easily worn machinery installation. Of approximately sixty submarines which were in service at the North Sea bases during the summer of 1917, there were on the average only twenty-three at sea at one time, the others being under overhaul in the dockyards. Of these twenty-three boats only about one-third of the number were actually in operating areas. The unfavorable strategic situation in regard to England is shown very clearly by these figures. In this connection the location of the bases in Flanders and in the Mediterranean was far more favorable; a fact which contributed largely to the greater measure of success obtained by the smaller number of boats operating in those zones. To this should be added the fact that long cruises and the necessity for keeping at sea for correspondingly long periods demand submarines of the larger type. The long period of construction of this type of submarine makes it difficult to keep the number up to the normal requirements.
However, the number of boats available, as shown by the foregoing, plays a very important part in the effectiveness of the submarines; the more so, the further the operating zone is distant from the base.
When we summarize the results of the submarine commerce warfare throughout the entire war, without going into the disputed question regarding the total amount of ship tonnage actually sunk, according to all the evidence now available, it may be stated that the submarine warfare, in spite of Germany’s unfavorable strategic situation and in spite of the energetic anti-submarine offensive, came very close to exhausting England’s resources.
This was not due alone to the loss of shipping and the valuable cargoes of munitions which were sunk, but also to the holding in check of other war strength as a result of the submarine warfare. Some figures will illustrate. About 13,000 guns of medium and light caliber were mounted for the arming of the English merchantmen; while it is estimated that about 65,000 men were required for the service of the guns. For the mine-sweeping operations in 1917, 3,200 English craft with a personnel of 25,000 men were kept in service. The munitions required, for the service of the batteries on the English merchant ships and auxiliary vessels, as well as the quantities of explosives required by England during the war for torpedoes, depth charges and mines, amounted to about 46,000 tons, according to conservative estimates. This is equivalent to the total output of one of the largest German munition factories for a period of one whole year. In Germany the total personnel required for the manning, overhaul, repair, and replacement building of submarines and at the dockyards amounted to 112,000 men; in England, there were required for the manning, overhaul, supply, and replacement of patrol vessels as well as for the construction of vessels to replace losses by sinking, 770,000 men. In all, 112,000 against 770,000 men. This entire strength of personnel as well as the large quantities of war material would have been available to England for the conduct of the war on land had Germany not inaugurated the submarine campaign. On the German submarines at the front during the war there were, according to the most careful estimates, about 13,000 men in all. Of these, 5,087 were killed. As opposed to this relatively large loss in personnel, which, however, was really very small when compared to the great losses sustained elsewhere in the war, there stand: first, the sinking of shipping tonnage almost equal to the entire British merchant tonnage before the war; and further, the diversion of other enemy war strength. With a sacrifice of 5,087 combatants, 770,000 men were held in check.
The question as to whether the German submarine warfare might have led to success and under what conditions this would have been possible lies outside the scope of this article. Suffice it to state here, that the attack of the German submarines on the overseas shipping and imports of their most dangerous enemy, as well as the effect of this campaign on the auxiliaries and fighting strength of the Allies, came very close to paralyzing them decisively. The possibility of success and the vulnerability of England have been proven. As long as submarines exist they will continue to be a threat to those nations which are unconditionally forced to rely upon overseas transportation. The study of the causes of the failure of the German submarine campaign will be of interest to certain nations in their preparations for war against certain possible enemies; but likewise the problem must be studied as to the extent to which the sources of Germany’s strength are available in their own country. A glance at the chart shows that the war harbors of France in relation to England are far more favorably situated than those of Germany. The time required for approach would be short, while there would be no narrow straits of Dover to pass. Further, for those countries bordering on the Mediterranean, there would be favorable strategic bases for submarine operations against any possible enemy. With these geographic relations of the European countries, the number and type of submarines employed by Germany during the war, may well be used as a basis of consideration by other navies. With either the Atlantic or the Pacific Ocean with their much larger dimensions under consideration as a theater of war, a greater number of submarines of the larger type come into consideration; boats having a large radius of action and good sea-keeping qualities. The larger submarine types, however, require long periods of construction with high costs; while the rapid increase of the number of such submarines in time of war would present a very difficult problem. The establishment of a base in the vicinity of the zone of submarine operations would then probably be the best solution of the strategic problem. That the technical qualities of the boat, its complement and command should be equal to the most exacting demands of the service, is essential for any vessel in war opposed to a powerful enemy, but for the submarine service these conditions must be especially emphasized. But to an even greater extent must be noted here the necessity for a large number of submarines. The restricted zone of tactical effectiveness of the individual submerged submarine, the long period of overhaul essential after every undertaking, the losses suffered as a result of an energetic anti-submarine offensive, all combine to make the number of submarines of the greatest importance. That the capacity of the submarine bases should be adequate and the machinery installation of the boats reliable, goes without saying. But no navy will be in the position of having as many submarine flotillas in service in time of peace as will be required for war. Therefore, a rapid increase in the number of submarines after the outbreak of the war will be of decisive importance in the event of a protracted war. One of the necessary conditions for this, if the state is to be able to meet the requirements of a large scale submarine offensive, is the possession of an adequate foundation in material and personnel which may be drawn upon for the creation of boats of fighting effectiveness for service at the front.
The subject matter contained in the last few paragraphs dealing with the submarine commerce warfare of the German submarines during the war also applies to the purely military employment of these boats during the war, the only exception in that case being that in judging the strategic situation the relations were not so unfavorable for the German submarines. With regard to the radius of action of the submarines the distances were limited by the North Sea; the war zone under consideration. The course of the British naval forces, when operating against the German Bight, or better, when they put to sea to make contact on the report of the German Fleet standing out, was on the whole predetermined by the conditions. Thus the direction of attack for the German submarines was fixed from the start. If we compare this strategic situation with war conditions in the Pacific Ocean and consider the immense distances which then come into play, one can realize that the strategic conditions for the German submarines were not exceptionally difficult.
But in only two periods of the World War were the German submarines available for strictly military service in the naval warfare to any appreciable extent—from the beginning of the war until the first initiation of the commerce warfare in 1915, and in the summer of 1916 when the submarine commerce warfare around the waters of England was discontinued. On closer examination it will be noted that the methods of employment of the submarines in these two periods were fundamentally different. In the operations of 1914-15 the mission of the submarine was to act singly in attacking possible enemy vessels in certain definite operating areas, or to lie in wait for such craft in the vicinity of one of the enemy harbors. On the other hand, the plan of submarine operations in 1916 was based on the idea of bringing groups of submarines into position to attack the enemy main body in joint operations with the fleet.
In the first period the following successes were attained as a result of the individual operations of the boats; September, 1914, JJ-21 sank the English light cruiser Pathfinder near the Firth of Forth, U-9 sank the armored cruisers Cressy, Hogue, and Aboukir in the southern North Sea; October, 1914, U-9 sank the cruiser Hawke in the northern North Sea; U-27, the aircraft carrier Hermes near Calais; U-21, the gunboat Niger near the Downs; December, 1914, U-24 sank the English battleship Formidable in the English Channel; June, 1915, the U-38 damaged the cruiser Roxburgh by a torpedo hit in the northern North Sea.
In order properly to evaluate the plan of operations which led to these successes, due consideration must be given the strength of forces employed. The above mentioned successful undertakings were only a few of the many which were conducted by the German submarines during that period without result. At that time German submarines were engaged in practically uninterrupted cruises in the North Sea seeking opportunities for attack. By far the greater part of these boats were not favored by luck, and many did not even sight a single unit of the enemy forces. Many were forced to return to their bases owing to inclement weather or owing to irreparable damage to the machinery installations; many only sighted enemy vessels in the distance and could not approach to within torpedo range on account of the low submerged speed of the boat, while others missed with their torpedo shots when an alert enemy sighted the torpedo track and sheered out. All in all, to obtain a slight result a great expenditure of force was necessary; the principle involved was unquestionably not rational. And what was the final effect of such German submarine activities on the general situation of the war at sea? After the sensational success of the U-9 in September, 1914, even some of the experts were prone to overshoot the mark in their conclusions, and were inclined to the opinion that the supremacy of the battleship had been placed in question by the submarine. This, however, was in no wise the case. The command of the sea held by the British naval forces, the fighting strength of which was embodied in their battleships, was in no way fundamentally disturbed. The overseas trade of Germany remained throttled as before. But still something notable was achieved by the German submarines. The British naval forces which were assigned to the task of patrolling the North Sea were forced to remain at a respectful distance from the German coast. Even in the northern North Sea, and later, in the waters to the westward of Great Britain, and finally in the bases themselves, the English naval forces were for some time in a state of insecurity. No one describes this more vividly than Admiral Jellicoe himself in his book entitled The Grand Fleet; 1914 to 1916. Those vessels which were at sea were forced to steam at high speed with constantly changing course and to consume much extra fuel at the expense of their sea-keeping qualities, while the personnel on the bridge, at the boilers and in the machinery spaces were subjected to continuous strain. The protection of the vessels at sea and the patrol of the coastal waters necessitated the employment of an enormous number of small, fast sea-going convoy and patrol vessels. From all this the German naval command profited to the extent that practically the entire North Sea, aside from a few English raids, was free from all large enemy warcraft. The British operations against the German coast and the island of Helgoland, which were seriously discussed and advocated by the British Admiralty, were not attempted, and the fact that the route was clear for a German raid on the east coast of England, must be attributed to a large extent to the influence of the German submarines.
Still another strategic advantage, which was not apparent to the outsider, was obtained by the German naval command as a result of the submarine operations. They were constantly informed as to the disposition of the North Sea patrol forces as a result of the continuous reports of the submarines at sea, and were thus enabled to obtain the essential oversight and estimate of the situation in certain areas when planning particular operations. Thus the submarines acted as far advanced scouts in furnishing definite strategic information to supplement the relatively weak air reconnaissance; independent of their own command of the sea. With the increasing range of the radio installations of the submarines during the war the radius of this distant scouting became greater. This range was finally extended far beyond the limits of the North Sea and may be taken into important consideration in theaters of war even more extended than those which come into consideration in a European war.
But in spite of the achievements of the submarines in the early part of the war—which are not to be underestimated, and in spite of their strategic effectiveness in extending the coast defenses, it must be repeated that the individual submarine operations in the first two years of the war produced few results as an offensive, while the method of employment was very uneconomical. There was a great expenditure of strength, considerable useless strain on both personnel and material, the opportunities for attack in the open sea were exceedingly small and a matter of pure chance, and the activities in the vicinity of the enemy coast were made extraordinarily difficult as a result of the enemy counter-offensive. Therefore there was no appreciable equalization of the fighting strength of the fleets brought about by the submarine operations in preparation for a decisive fleet engagement. In the nature of things such a result cannot be expected of the submarines.
These considerations led the German fleet commander in the summer of 1916 to another plan of submarine operations. The attempt was then made to assemble the submarines in a certain area over which the enemy would in all probability be forced to pass, or to entice the enemy by movements of the German fleet to pass a position to which the submarines had been opportunely directed. The details of the primary plan were as follows—when the appearance of the German fleet in the North Sea had been reported, the main body of the British fleet would stand out to sea from their bases. If the fleets made contact then the damaged vessels would return to their bases under much reduced maneuvering power. During the period when the enemy ships were standing in and out of their harbors, which could be fairly closely determined, the large number of German submarines near these harbors must certainly find opportunities for attack. Thus there would be no long period of waiting or searching for vessels to attack but a concentration of a number of boats in a favorable position for attack in order to compensate for limited range of visibility and area of operations of the individual submerged boats. Such a plan was prepared toward the end of May, 1916, for joint operations of the submarines in connection with the Battle of Jutland—it ended, however, in a failure. From May 23, 1916, on, the submarines in the North Sea available for service lay in the vicinity of the English war harbors, ten near the Firth of Forth, and Pentland Forth, and two near the Humber, with orders to remain on station until the evening of June 1. The German fleet, however, was forced to postpone the operations planned for May 23 until the end of the month for reasons of the gravest importance. When on May 30 the decision was made to stand out, the commander-in-chief of the German fleet directed that a radio be dispatched ordering the submarines to remain on station one day longer. But this order was received promptly only by a very few of the submarines; and either too late or not at all by the majority of the boats, since they were stationed very close in to the enemy coast and were forced to remain under water for a great part of the time by the enemy patrols and were therefore deprived of radio communication. Practically all of these boats were exhausted as a result of being held for eight days on station in the immediate vicinity of the enemy patrols. The English fleet left its anchorage at midnight May 30-31 and thus passed the position of the majority of the German submarines during the hours of darkness without being sighted. Only two boats, which had meanwhile shifted position to a greater distance from the English coast, sighted parts of the English force, standing out at daylight on May 31. These two submarines, which were surprised by the enemy suddenly coming in sight out of the mists, were unable to make a successful attack. Thus it occurred that the majority of the submarines remained in ignorance of the battle which took place on May 31 and June 1, and had already left their stations at the most favorable moment when the English fleet was returning to its bases after the battle. It was purely accidental, then, that in spite of this, on June 1, a submarine encountered each of the damaged battleships, Marlborough and Warspite, which were returning unescorted to port. Two misses in the heavy sea, again proved the limited value of a submarine acting singly against a freely maneuvering, alert enemy. Thus this first undertaking of the submarines operating in conjunction with the fleet at the Battle of Jutland proved a failure.
However, one cannot say that the underlying principle planned in these operations was necessarily a failure. The lack of success must rather be attributed to the manner in which the boats were disposed and the resulting lack of possibility of communication. It was shown by these operations that the premature disposal of the boats close under the enemy coast and within the effective zone of activities of the enemy patrols was a mistake. The submarines are thereby forced under water during the daylight hours, radio communication is interrupted, and the crew is tired out and unable to obtain the necessary relaxation even when the boat comes to the surface to re-charge batteries at night. Further, if the enemy fleet happens to be already at sea before own fleet operations commence, then such waiting in the first period, before the battle, is necessarily a delusion.
On August 19, 1916, an advance of the German high seas fleet toward Sunderland, on the east coast of England gave an opportunity for a practical application of the submarine experience obtained during the Battle of Jutland and for developing the submarine operations in conjunction with the fleet one step further. This time the initial position of the boats was in the form of movable lines, which although based on the coast, still extended well out into the open sea, disposed in such a manner that the enemy standing out from either the harbors to the northward or southward would in all probability have to pass over one of these lines of submarines. In general these boats could remain on the surface in readiness to receive orders transmitted by radio. The commander of submarine forces was embarked on one of the battleships of the High Seas Fleet and was able as a result of reports received from the airships and some of the submarines themselves to direct the line of submarines in the direction of the reported enemy main body by means of radio instructions in accordance with the prearranged plan. All radio messages in this connection were correctly received by the submarines and fulfilled their purpose of directing the submarines toward the enemy course. One of these submarine lines comprising six boats was stationed initially in the latitude of Sunderland while another comprising four boats was in position directly across the mouth of the Humber. The calculations of the German commander-in-chief proved correct. Of the ten submarines, six were able to sight the enemy and five were enabled to fire torpedoes. Of the twenty torpedoes fired on August 19 and 20 by the submarines, eight were hits. The cruisers Nottingham and Falmouth as well as one destroyer were sunk in spite of their high speed, strong escort, and depth charge offensive; further a hit on one of the battleships was reported as certain by one of the submarine commanders, but so far as known, was not conceded by the British.
The great effectiveness of the German submarines on that day was again vividly portrayed in the previously mentioned book of Admiral Jellicoe. His impressions and the conclusions which he has drawn from this attack are cited in the following extracts from that work:
The numerous submarines already sighted made it probable that the trap was extensive; it was therefore unwise to pass over the water which he had occupied, unless there was a prospect of bringing the high seas fleet to action…During the passage up the searched channel a number of submarines were sighted and frequent, and in some cases, large alterations of course were necessary to avoid them; if all the reports were correct, the locality indeed seemed to be a hot-bed of submarines…The experience of August 19 showed that the light cruisers, proceeding at even the highest speed unscreened by destroyers, ran considerable danger from enemy submarines…Representations were made to the Admiralty to the effect that it was considered that in the future light cruisers should be screened by at least one destroyer per ship…The ease with which the enemy could lay a submarine trap for the fleet had been demonstrated on August 19…It was clear that it was unwise to take the fleet far into southern waters unless an adequate destroyer force was present to act as a submarine screen for all ships…If the circumstances were exceptional and the need pressing, it would be necessary to accept the risk. There was general agreement on this point between, the flag officers and the Admiralty.
A far-reaching and significant estimate of the submarines and their effectiveness.
No contact was made by the two fleets on August 19, 1916, since the German fleet was diverted to the southward by the report of an airship stating that strong enemy forces had been sighted to the southward of the German line of advance, although in reality the English main body was approaching from the northward. Thus on this occasion no opportunity offered for actually determining the prospects of success of a line of submarines during the deployment of the battleships for action and shortly after the action, when their movements were controlled by radio from a single station.
In this action it was not intended that the submarines should be drawn into action during the main engagement, any more than at the Battle of Jutland; it being correctly held that the submarines were not suited for employment in this manner.
Further joint operations of the German submarines and the battle fleet did not take place during the war, since after the beginning of 1917 the submarines were employed uninterruptedly in commerce warfare. Thus the chapter on the purely military employment of the submarines was prematurely brought to a close. But even these few actions suffice to show clearly what value may be attached to the submarines when engaged in strictly military operations in naval warfare. These gave the naval warfare in the North Sea a definite trend; the superior English fleet was held at a distance, and to a great extent they thus assisted in the protection of the German coast, while at the same time providing freedom of action for the German naval forces. In the same sense in which we speak of a “fleet in being,” a fleet which exerts its effectiveness merely by its presence, so we can apply this idea to the submarine weapon. The enemy is restricted to a certain extent, since at any time this weapon may threaten a certain position. It is also correct to designate the submarine as an essential defensive weapon of the weaker power. Although it may be pointed out that the coast of Flanders was repeatedly bombarded by the British monitors in spite of the presence of the German submarines stationed there, it should be noted that these waters possessed very exceptional navigational conditions and that the monitors were able to seek protection among the numerous sand shoals which made submerged maneuvering on the part of the submarines a practical impossibility. One need only recall the appearance of the German submarine U-21 off the Dardanelles toward the end of May, 1915, to realize the great effectiveness of a single submarine against a strong force engaged in bombarding the coast. However, it must be emphasized that a single submarine will in general not suffice for coast defense. There must be means at hand to keep open a passage for the submarines to stand out, against enemy efforts to block such channels. In those localities where nature has not provided favorable coastal formations and great depths of water, the support of a strong, effective fleet will be essential to the submarines.
With regard to the offensive employment of the submarines, one frequently hears the statement that they can only be used for attack in commerce warfare and in the role of “pirates.” However, he who reads the conclusions of the British commander-in-chief quoted above pertaining to the action of the German submarines on August 19, 1916, will be of another opinion. To this should be added only that the methods of employing submarines as an auxiliary in naval warfare have not been developed to the highest state of perfection. As stated before only two engagements took place and in both only a relatively small number of submarines participated. Valuable experience was obtained from these. However they cannot longer be applied in actual warfare. The careful training in the cooperation of all branches of the service, which is as important to naval warfare as to war on land, was not carried through to its final conclusion in the case of the submarines. This cooperation of the submarines is of particular importance since the inadequacy of the submarine acting singly was thoroughly demonstrated. So much is certain; the high state of the technical development of the modern submarine offers a wide field of activity for the offensive employment of the submarines along the lines indicated.
One final question now remains to be considered—what does the technical development of the future offer for the submarine? Are we on the threshold of undreamed possibilities for this weapon which was developed into such a surprisingly important factor during the World War? Is the submersible of the future to force naval warfare to assume other forms and possibly to displace the battleship in its present day supremacy on the seas?
With regard to technical developments one must guard against any prophecy for the distant future. What is stated in regard to the questions above propounded can only be applicable to the near future and only in so far as may be indicated by the trend of present developments. Without doubt, the beginning of this development is to be found in the increase of displacement, to which most of the important navies of the world are already committed in their new construction, since the conclusion of the war. This decision was largely due to the desire to increase the effectiveness of the submarine corresponding to the war-proven importance of this weapon, to strengthen it in every respect and to make it suitable for employment in widely extended theaters of war by means of increased sea-keeping qualities and radius of action. But it appears further, that an increase in displacement will not only result in an increased radius of action, but with proper discernment will also lead to greater effectiveness from both a strategic and tactical standpoint; as well for strictly military operations of the submarines as for commerce warfare, on occasion.
The principal objection raised in the past to the employment of the submarine as a weapon in commerce warfare was that the submarine was not in a position to safeguard the lives of the passengers and crew before sinking a large merchant vessel. With regard to the submarine as it existed during the World War this is, of course, an undisputed fact. However, a new prospective is opened up by the submarine cruiser of over 3,000 tons. Under these circumstances the question might then be re-opened by those who are interested in this procedure. It is probably now possible to construct a submarine cruiser in such a manner that the passengers and crew of a large steamer might be temporarily accommodated on board, and the cruiser would thus be in the position to conduct commerce warfare in the same manner as surface cruisers during the World War and in former times; in accordance with the “Rules for Prizes.” By means of such submarine cruisers the commerce war would then be conducted on the high seas, beyond the point where the danger from mines and small patrol vessels with their threat to the submarine could be extended. Airplanes carried by the submarine will still further extend the range of effective visibility. Heavy armor and a strong armament will further serve to make such a submarine cruiser a dangerous opponent for a protected convoy and it will be enabled to combat successfully all offensive measures which were employed against the German submarines during the war. The submarine cruiser will certainly be far superior to any other special type of craft as a privateer owing to its great radius of action and also its possibility of withdrawing from a superior force by submerging. Such a craft will be difficult to annihilate.
Increase of displacement may also be utilized to increase the speed of the submarine. An increase in speed of the submarines was already achieved toward the end of 1918 by improvements in the machinery installation as a result of further developments in the technique of motor construction without involving increased weight. If it is possible to increase the speed of the submarines to a point where they are enabled to accompany the fleet—and this appears to be about the limit of the future possibilities—then the joint tactical operations of the submarines and fleet may be further perfected.
The operations of the submarines with the fleet as described on August 19, 1916, must be designated as primitive. The greater the speed of the submarine, the closer the tactical cooperation with the fleet during the approach and the easier it will be to direct the submarines to favorable tactical positions for attack after the enemy has been reported. Further, the perfection of the underwater signaling devices promises to be advantageous in this connection. In practice the expert will be confronted by other problems, one of which will probably be the still unsolved question of the German submarine cruisers; the proper seaman-like handling of the large submarine in a heavy sea. In this article, we can only indicate the theoretical lines of possible development which may result from further technical improvements.
Like all implements of warfare, the submarine will be further perfected from both a technical and military standpoint; its field of activity will be increased, and it will become a more effective weapon in naval warfare.
New methods will be developed to combat the submarine and the methods of conducting naval warfare will change to meet the situation created by this new weapon. With all of the above, so far as one can conceive, there is nothing radically new, nothing which is calculated to revolutionize the present concepts of naval warfare that mankind may imagine. Above all there are two sources of weakness which appear to be inseparably connected with the nature of the submarine—the fact that the submarine must carry a double-machinery installation, for surface and for submerged cruising, as well as the restrictions imposed on the submerged submarine in speed, radius of action, and range of visibility. The technical problems involved appear to be incapable of solution at present. Meanwhile, the inferiority of the submarine as against an equally large surface vessel—all in all, type for type —will remain. None of the other types of vessels developed for naval warfare will be reduced in effectiveness as a result of the submarine development, or radically influenced in its field of application.
As before, the battleship will remain supreme in war on the sea.
Still less, however, have the anti-submarine measures developed during the war succeeded in causing the submarine to be displaced. All indications point to the fact that this type will increase in value for naval warfare if its further development is not forcibly stopped by other means.