1942: Naval Science, American

Naval Strategy of the United States.

Prior to 1940, little thought had been given to the possibility of a war of such magnitude that the United States might be simultaneously involved in both oceans. The alignment of the great maritime nations seemed to preclude such a contingency. However, with the fall of France, the question mark over the French Fleet and the damage sustained by the British navy made a two-ocean fleet for the United States a live issue that fortunately was readily accepted by the nation following the courageous lead of the Chief Executive.

In December 1941 the situation in the Pacific had become critical. Much naval force had been diverted to the Atlantic to maintain the neutrality patrol. But there remained a fleet in being in the Pacific that was superior to the Japanese strength and sufficient to hold Japanese aggression in check.

Pearl Harbor had its influence on the balance of naval power in the Pacific. It precipitated the United States into a two-ocean war with unexpected suddenness. The nation was caught unprepared for war on such a scale, but fortunately the naval building program was under way and capable of great acceleration.

From a strategic point of view, it was soon evident that Hitler had to be handled in the Atlantic before the crushing blows were delivered to Japan. In other words, the Allies had to take the offensive in the Atlantic and a more or less defensive role in the Pacific, holding the line, Alaska, Midway, Samoa, New Zealand, and Australia.

This strategy appeared to be sound in the early part of 1942. Then the enemy really struck with devastating force in the Atlantic. The Nazis had been successful in more than trebling the number of submarines they had at the start of the war. They turned them loose in packs against the North Atlantic convoys off the East coast of the United States; in the Caribbean, a hot-bed of submarines; in the Gulf of Mexico, and on down into the deep South Atlantic.

This phase of the war in the Atlantic caught the American coast sadly in need of defensive weapons, with the result that a disastrous toll of valuable ships and cargoes was taken. Herculean efforts were made to turn out destroyers, subchasers, patrol boats, and the necessary gear for submarine hunting which included the development of sound gear, depth charges, and naval armament. Blimps, planes, convoy escorts, and coastal reorganization were thrown in to combat this grave menace.

At about this time the Japanese, flushed with success on the Asiatic mainland, Philippines, and Dutch East Indies, projected their operations into the southwest Pacific Islands preliminary to a frontal attack on Australia and New Zealand. It was excellent strategy on their part to sever the direct lines of communication with the United States and the Antipodes. This threat had to be met. In the meantime, the Japanese over extended by an invasion of Alaska and an expedition against Midway. The Coral Sea and Midway defeats were unexpected, and a bitter blow to Japanese prestige. They served as a deterrent to further aggressive action to the eastward, although the threat against Australia was still imminent.

To protect the vital lines of communications to Australia, the United States resorted to a daring amphibious raid on the Japanese-held Solomon Islands.

The United States was at last on the offensive, and the end of the year found Japanese air power being depleted gradually in the Pacific and the United States gaining strength.

On the Atlantic, the huge task of getting convoys with war materials through to England, to Murmansk, Russia, and to the Near East has taxed the ingenuity of the American Navy. From a low ebb in midsummer, the means to combat the submarines have been accumulated in sufficient strength to reduce the sinkings and get convoys through with minimum losses. By the end of the year the situation was in hand.

The African Campaign was launched on Nov. 7 by the most powerful amphibious force that ever crossed the seas, as a unit, in all history. Convoyed by the American and British navies, this expedition was well conceived, well timed, and beautifully executed.

Influence of Air Power.

Even prior to the war, the U. S. Navy was proud of its well-organized and efficient air force, made up of a magnificent personnel, in fact, the pick of the Navy. The first year of the war has depleted this crack force greatly, but a heavy toll of the enemy has been taken in the Pacific. A very noticeable loss of efficiency has been noted in Japanese pilots which indicates that American flyers — Navy, Marine and Army — have worked them over very well. The Japanese have lost a tremendous number of planes and trained pilots. Their replacement of both has been inferior in quality and it is believed that this condition will be magnified as the war goes on. On the other hand, American planes are getting better and better and decidedly more numerous, while the quality of pilots remains at a high standard.

The main lesson the Navy has learned is the effect of the number of shore-based aircraft. Quantity production keyed to maximum capacity in all the war countries has produced an unheralded number of planes that have and will continue to play an unheard-of role of importance on the conduct of the war both at sea and ashore. This mighty air arm will not supercede either Armies or Navies, but it will have a tremendous influence on both land and sea tactics.

However, it took actual warfare to demonstrate that superiority in number of planes in the theater of operations would not necessarily mean air superiority in that area unless the numbers in excess were overwhelming. For instance, while Germany had a ten-to-one superiority over England in the all-out 'blitz,' she never attained control of the air over England and, as a result, the 'blitz' ended in an aerial defeat for Germany. On the other hand, Germany had such a marked superiority in aircraft over Crete, that she was able to crush the Allied air force and would have been successful in destroying the British Mediterranean Fleet had it not hauled out.

Plane carriers are very vulnerable to massed plane attacks from either shore based planes or other carrier based planes. The war in the Pacific has clearly demonstrated this. At the same time the modern battleship has stood up remarkably well in all encounters far removed from home bases. It has been the backbone of the American Naval Task Forces carrying on amphibious operations so successfully in far-flung reaches of the Pacific. Added protection and increased anti-aircraft fire control have enabled this class of vessel to score heavily against both Japanese surface and air forces. They have also taken hits from submarines and carried on their operations at undiminished speeds.

Airplanes and Surface Ships.

Ever since the advent of the military airplane, the controversy concerning the relative merits of that medium of warfare and that of the surface ship has been the subject of enumerable articles and many debates.

Much has been learned from actual combat in the past year about the relative merits of planes and surface ships. On the whole, this information is strictly confidential. Suffice it to say though that although many war ships have been bombed and sunk by aircraft, many aircraft have likewise been shot down by surface craft. The plain fact is that the airplane has added to the complicated art of warfare. Neither the surface ship nor the plane can ignore each other. The airplane has not eliminated any type of surface craft nor is it likely to do so.

The primary purposes and uses of surface ships and airplanes are not by any means identical. Their characteristics are so utterly different that each possesses few of the primary characteristics of the other. It happens then that neither can be evaluated in terms of the other. Both are necessary military weapons in due proportion depending on the objective.

Design of Air and Sea Craft.

There are three elementary military characteristics embodied in all mechanical apparatus utilized in the prosecution of war. These are armament, protection, and mobility. Armament is exemplified by guns, bombs, torpedoes, and depth charges; the protective element by armor plating, artillery shields, and the pilot's armor in planes; and mobility by power plants. Of the elements the protective element is entirely defensive, while the other two are mainly offensive in character except that mobility may be, and, indeed quite often, is used as a defensive measure. All of the elements require detailed preparation prior to their incorporation into any weapon of war. However, their combination in the mechanical apparatus must be predetermined in order to fit that apparatus for its destined use. Compromises and sacrifices must be accepted in all the apparatus. This is particularly true of any mechanical device for use in the air or on the sea.

In building a warship all three elements must be limited, and one or two of the characters may be enhanced but only at the expense of the remainder. Thus a destroyer gains mobility at the expense of protection and a battleship gains protection and armor at the expense of its mobility and speed. However, the larger the ship, the higher the degree of all the three elements that may be combined in her. This fact is the reason for the increase in size of battleships from 35,000 tons to 45,000 tons and the destroyers from the World War I tonnage of 1,200 tons to the present tonnage of 1,850.

In building an airplane, it is found that on more and more drastic limitations must be accepted and more extensive compromises made, as it has been found that only one of three important elements can be incorporated to a high degree. This accounts for the high speed, the relative weak armor, and limited weight-carrying capacity of airplanes. The mobility of the plane, however, has two characteristics not shared by the ship, one is its ability to climb and the other its inability to stop in the air. The ability of the plane to climb gives it the advantage of position from which it may be used either in diving or bombing. The inability of the plane to stop or hold an advantageous position for longer than an instant requires that some other mechanical apparatus must be used to consolidate its gains.

As in a ship, the larger the plane the higher the degree of adaptability of the three essential elements, thus we see the creation of monsters such as the 'Mars,' and the prospective air battleships envisioned for the future. These larger planes, while incorporating more armor and protection, however, must still sacrifice some mobility to gain these increases. Thus we see that every device utilized in war must be a compromise based on judgment as to what its ultimate use is to be and what it is to accomplish during its lifetime. In addition, it must be borne in mind that the materials and skill of fabrication are available for all mechanical apparatus and thus all weapons eventually arrive at a balance of potentiality when combined in proportion and when put to their proper use.

There is a vast difference in degrees of stamina and immunity from damage of the different types of planes and ships, although none of the types of ships or planes is indestructible. Each of the types has its weakness which the designer and the manufacturer hope to minimize by their skill, and the tactician endeavors to minimize by the use of supplementary craft to supply the deficiencies and by the proper handling of the entire combatant force. Depending entirely upon the problems to be met, all types of planes and ships are necessary to a naval campaign. The specific operation to be undertaken dictates the choice of the types, as each can be dispensed with under some circumstances and each of them is necessary under other circumstances. The surface ship, when used against the bomber and torpedo plane, attains its maximum power of survival by being given a reasonable immunity from probable mines, torpedo, bomb, or projectile hits, provided it is properly employed tactically and provided it is used in conjunction with suitable supplementary types of warship.

Each type of plane and each type of ship is designed and built to counter or overcome the military characteristics of one or more other types under certain circumstances or when used in combination with other types of plane or ship. A submarine, for example, is designed so that it may hit a carrier with a torpedo unobserved. The destroyer hopes to kill the submarine while the cruiser hopes to bag the destroyer. The battleship, in turn, hopes to eliminate the cruiser, while the torpedo planes and bomber from the carrier hope to sink the battleship, and the fighter plane hopes to down the bombers and torpedo planes. The designer strives ever to provide a type which will create the maximum damage with the least jeopardy in attacking, but will suffer the least damage when hit itself.

As previously stated, national policy affects the fundamental design of all military mechanisms. For example, if it is known in advance that ships of the Navy will never be required to fight more than a few hundred miles from a well-protected home base, weight saved from fuel can be built into guns or armament. Similarly, if it is known in advance that a fighter need carry gasoline for but a short time in the air, then its maneuverability and armament can be improved.

In every ship and plane built by the Navy one or more of its outstanding characteristics is emphasized so that it may have an advantage in specific particulars. This is done deliberately, and only after all the occasions of its prospective use are examined thoroughly by experts.

Sea Craft.

The outstanding quality of a submarine is its ability to submerge. However, a submarine when submerged too deeply becomes helpless in the face of proper counter weapons. Its design depends upon considerations of buoyancy and mobility. It is physically impossible to build a submarine which will withstand pressures encountered at great depths, or to provide the submarines with any appreciable amount of protective armor. In addition, the limitations of power plants operating under water are so critical that design becomes a matter of extreme compromise. Every round of ammunition, every ton of fuel, every torpedo put into a submarine becomes a matter of detailed consideration. A submarine, however, because of its peculiar properties, has a usefulness in modern warfare which is not shared by any other type.

The outstanding characteristics of a destroyer are its speed, its maneuverability, its ability to carry depth charges over submarines, and its torpedo armament.

The cruiser with its increased tonnage carries still greater power than the destroyer. The volume of gunfire, greater stamina due to increased compartmentation and thickness of plating, as well as increased radius of operation and greater sea worthiness combine to make the cruiser a weapon of greater potentiality than the destroyer. However, the cruiser with no great amount of armor for the protection of sides and decks, is still a compromise.

An increase in size of the vessels gives us the battleship, with its outstanding characteristics of crushing gunfire against all types of surface craft, increased protection against damage by any naval weapon permitted by increased tonnage and relative lower speeds and maneuverability than possessed by the cruiser or destroyer. The outstanding characteristic of the battleship is gunpower. However, she is expected to demonstrate the maximum power of survival against all naval weapons and ability to keep the sea.

The newest type of combatant ship is the aircraft carrier, designed specifically to carry planes of the types that have been determined on. Carriers must possess speed to make them of maximum usefulness to their planes. They must have size to provide a large landing deck and a stable platform at sea for plane landing and take-off, and capacity both on decks and in hangars for the accommodation of planes. No carrier can have complete armor to protect its planes, gasoline and ammunition. Nor can its flight deck, located high in the ship, be heavy enough to resist bombs or gunfire to the most desirable degree or to the degree possible in a battleship. Every gun, every ton of fuel oil or gasoline, and every knot of speed put into a carrier reduces the number of planes that can be carried. Here too, compromise has played an important part in design.

Air Craft.

Our naval weapons of the air include several types of planes, each of them, like the several types of ships, useful to each other and to the ships beneath them for certain purposes. All military planes are alike in one particular; they possess speed, engine power, and limited weight to enable them to attain the advantageous positions of height with rapidity and with practicable limitations to enable them to land at landing fields or on ships. The high speed and high power that are so essential for the successful operation of the military plane are inherently uneconomical.

Increasing the radius of action of the plane by the addition of increased fuel capacity reduces the number of guns, the amount of ammunition or bombs, and the personnel which can be carried, as well as restricting its maneuverability. All others must be limited if any one character is pushed to its limit, hence the design of a plane is a critical matter. Planes require a suitable landing place and frequent servicings. They require ample space in which to maneuver, for collision is fatal. It is necessary that they reach exact positions in the air in order to create the maximum damage with their limited load. They cannot stop in the air nor can they hold any position for more than an instant. A considerable number of planes are necessary for effectiveness, but vital needs such as maneuvering space and fuel are opposed to numbers. It is also an important fact that while at times planes may accomplish significant destruction or damage, they cannot remain to conquer.

There was a time when the airplane was considered a cheap weapon. However, that is not the case, for not only are great numbers required, but any light mechanism that operates at high speed and possesses high power is not cheap. In addition to the planes themselves, accessories such as landing fields, hangars, repair shops, barracks, supplies, carriers, transportation, highly specialized personnel, and training add immensely to the cost of air power.

Carrier planes, on the whole, should be less capable than land planes because of the limitations placed on their size and weight by the strength and capacity of their landing decks. Sea planes are still less tactically capable than carrier planes, due to their physical characteristics. However, the carrier planes, by taking their landing fields with them and thus affording opportunity for upkeep, relaxation of personnel, and assistance in time of need, in addition to increasing their radius of action, tend to approach the land planes in tactical capability.

Each type of plane, as in each type of ship, has its peculiar characteristic incorporated in its design to the highest degree, making that particular type superior to some other type, and constituting the reasons for the type itself.

The bomber enjoys the advantage of position when achieved, but in order to take advantage of it, it must come to that position at precisely the correct time. The gasoline load and the bomb load of a bomber are limited so that a compromise must be reached between these and the elements. The inherent range of a bomber may be considerable but before it starts on its mission it is irrevocably committed to a certain ratio between its bomb and gasoline load. When that choice has been made, it cannot be changed, at least not until the limited load has been expended or until the bomber has returned to its base.

The torpedo plane's principal advantage is its speed. Like the bomber, it can attack in numbers provided it is not intercepted at a distance. Like all planes, it is much hampered by low visibility and bad weather, and similarly it is useless and vulnerable when down.

Fighters are essential for covering and defeating bombers and torpedo planes. A fighter is fast but essentially vulnerable, possessing great speed and maneuverability, gained at the sacrifice of fuel and protection. It is, however, necessary in the tasks which it is designed to perform.

Weapons on Ships and Planes.

The weapons of each of the types of ships and planes mentioned above are more or less peculiar to the machine itself and are the results of the great skill of the designers and manufacturers. The object of each is, of course, the fatal destruction or damage necessary to produce victory for the owner, or defensively to prevent such destruction and deny victory to the enemy.

The primary naval weapon is the gun which shoots projectiles. As satisfactory guns are limited in size by the skill of the manufacturer, so too is the muzzle velocity and the size of the shell, and the resulting energy directly proportioned to mass times the square of the velocity is limited. The projectile may carry a large amount of high explosive in which case it must of a necessity have thin walls which rupture easily on impact, or it may carry a small amount of explosives with the resultant reduced explosive force. If the shell bursts upon impact it loses the advantage of bursting in a confined space. Hence, the designer must choose between a thick-walled and a thin-walled shell and an impact or delayed action fuse. Other considerations ordnance designers must take into consideration are the life of the guns and the weight and stowage space of ammunition.

Similarly, in a submarine the principal weapon of which is the torpedo, only a limited number of tubes can be built and only a limited number of torpedoes can be carried on board. Torpedo tubes and torpedoes must be designed to fit accurately. The explosive charge (war head) of the torpedo, together with its speed and range, must all be determined in advance, for a torpedo may be designed to run a short distance at high speed and a heavy war head, or to run a long range at slow speed with a light explosive charge. The torpedo war head bursting on the side of a ship possesses a destructive force proportional to the head of water above it and the amount and character of its explosive charge. Its destructive effect is countered in ships by the compartmentation proved by experience to be the most effective. The shell of the torpedo is of such limited strength that the height above water and the speed at which it is launched must be relatively small in order to avoid damage and consequent erratic run.

The destructive effect of a mine, like that of a torpedo, depends entirely upon the size of its explosive charge and the depth of water. The mine in some respects is the most destructive of naval weapons. Its large explosive charge and favorable position make it one of the most deadly implements of war, except in cases where its lack of controllability may seriously hamper its effectiveness.

The aircraft bomb, like the projectile, can be either an armor-piercing bomb with thick walls and a small explosive charge or a thin-walled high capacity demolition bomb. Those explosives which burst in the open air on impact, generally speaking, have a comparatively smaller disruptive effect on structures than those which first penetrate and then explode. In order to make an effective flight, a bomb must be released from one point in space exactly or it will miss. In addition, due to natural laws, that is, gravity and its effect on the maximum terminal velocity of a bomb, the striking velocity that can be achieved by a bomb is considerably less than that of a projectile. It is possible, therefore, to build shore establishments or ships which will usually defeat bombs of the size which can be carried in planes in any significant numbers. On any particular occasion choice must be made as to the size of the bomb to be carried by the plane, for a plane that is able to carry ten 100 pound bombs can carry but two 500 pounders or but one 1,000 pound bomb. Bombers cannot dive when carrying a heavy bomb load. Therefore, anti-aircraft weapons are used to keep them at great heights in order to minimize the percentages of hits, as well as to allow maneuvering time for the ships below.

Innumerable weapons incorporating great ingenuity of design have been invented and placed on test. However, the salient point is that compromise has been necessary in each and every one in order to endow it with its salient characteristic.

Principles of Strategy.

The various types of ships and planes are suitable for one type of campaign or even for various phases of the same campaign depending upon the types and location of the opposing forces. The High Command is charged with the duty of combining the various available types in such a manner that they will supplement each other and obtain the best results on any particular occasion.

In general, light forces, that is, planes, cruisers, submarines, carriers, and destroyers, are used for striking forces, for raiding, for reconnaissance, for screening purposes, or for attrition attacks. When used against more or less equal opposing forces, light forces tend to neutralize or greatly reduce each other as the campaign progresses. This naturally requires considerable replacements as well as growing support from heavier units. They may or may not be supported by heavier forces of cruisers and battleships as strength members, and they may or may not be followed by expeditionary forces comprising infantry, tanks, artillery, and air forces to hold territory. However, it is certain that if the sea lanes are to be held and used freely while denying their use to the enemy, they must be occupied in sufficient force to control them. It is equally true that the greater the distance of the area of control from the base of supplies and replenishment, the more difficult and costly becomes the problem of the belligerent on the offensive. An overseas venture involves control of the seas and the air and finally the land. Control in this sense does not mean the total liquidation of all opposing forces but rather only that they be sufficiently reduced for the feasible use of the desired areas.

Personal courage has a great effect upon the employment of ships and planes in action. The collective performance of a light force which knows that it is adequately supported by a heavy force is better than that of a light force which is without that support. Similarly the collective performance of a bomber or torpedo plane attack adequately supported by fighters and dive bombers is much more effective than one without such support. Such unsupported attacks have been readily dispelled or broken up by being met with adequate fighters or even anti-aircraft gunfire and have jettisoned their bombs or dropped their loads in the sea and gone home without accomplishing anything.

Naval weapons may be selected properly or improperly for any particular occasion or operation. Their proper selection, while at times dependent upon luck, requires the deep study of all available information by the responsible commander. Any military commander who depends entirely upon luck will eventually meet disaster. All types of ships and planes, as has been remarked before, may be used alone on some occasions and each may be dispensed with on others. Therefore, it is the duty of the High Command to select wisely and well from the units available those best suited to the particular task at hand. If the proper units are not available the result may be a national calamity through a failure to prepare properly.

Next in importance to the employment of the proper types of ships and planes is the Commander's selection of suitable objectives for attack. The expenditure of lives and materials on useless objectives can be regarded only as criminal negligence on the part of the responsible authority. Under existing conditions no major fleet or task force is complete without all types of ships and planes, including the many types of auxiliary ships for fleet maintenance and supply. This is particularly true in the prosecution of an overseas campaign.

Ships and planes are mobile, and maneuverability is one of their primary characteristics. It is, therefore, no more appropriate that ships be caught unprepared, stopped at sea, or anchored in a roadstead, than it is that planes be caught on the ground. During the necessary servicing periods required by both planes and ships, it is vitally necessary that they be guarded by other means than their own. In this connection common sense dictates that, unless there are compelling reasons, and benefits to be gained proportionate to the risks run, there is no more good judgment in sending capital ships into submarine-infested waters than there is in sending any valuable military force into an uncertain area or critical situation without reconnaissance or information on which to base an estimate of the forces to be met.

The effectiveness of all weapons is influenced to a decided degree by weather conditions. Bad weather disturbs all functions of all military weapons to a greater or lesser extent. Weather may be a friend or enemy, but normally bad weather tends to increase the inherent weaknesses of all types of military mechanisms. Some weapons, however, may be used in all kinds of weather and others only in some kinds. Heat, cold, ice, fog, rain, snow all have a tremendous effect. Daylight, darkness, sunlight, moonlight, twilight, and clouds exert an enormous influence. They may impose limitations and on occasion offer opportunities. The range of visibility too has a profound effect on and at times limits operations at sea and still more so in the air.

Under certain conditions a composite force of battleships, cruisers, carriers, destroyers, submarines, torpedo planes, bombers, and fighters must operate under reduced efficiency. This is because some of the types cannot operate at all or perform only at less than their designed efficiency. During rough weather the smaller ships being less seaworthy, must slow down, with a consequent reduction in speed of the larger units. Similarly, planes must be kept aboard or grounded during inclement weather.

To be of the maximum effectiveness an adequate force must attain its desired position at the desired time. This principle has been stated in more pungent words by General Jeb Stuart: 'Git thar fustest with the mostest.' To 'git thar' depends upon the speed, the distance to be covered, and the endurance of the units involved. Both the sea and the air are very large, but owing to the speed of the airplane for short air distances they may be assumed to be reasonably comparable. The endurance and speed of planes and surface craft are matters of a designer's choice.

Distance has a great effect upon the auxiliaries used in an overseas expedition. It is one thing when supply ships are based at an established Navy Yard or port close to their source of supplies, and quite another when they are located at an outlying spot to which everything must be transported.

Distance and weather are allies. They have at times brought grief and disaster to many military commanders.

As has been pointed out above, all military weapons have been designed to produce the maximum destructive effect of which they are capable. The majority of them are complicated to some degree. Therefore, in spite of the fact that a balance is necessarily established to some extent between the types of weapons by their designers, their effective use depends entirely upon the training and ability of the personnel who are to put them to their use. If it is granted that all designers are of equal skill and that manufacturers are all equal in the reproductions of the designers' ideas, then the superior training of the operating personnel will cause that particular weapon to prevail in the long run.

There is no substitute for an adequate number of well-trained personnel and there is no training which supplants experience and practice. Trained personnel has an influence on design as well as on operation in that, given the opportunity, it will suggest and cause to be effected, up-to-date changes in design. It will too, without hesitation condemn or abandon any inadequate weapon, including ships or planes, which has little merit or which does not have a good chance for survival.

Expansion of the U. S. Navy.

The rapid expansion of the United States Navy during the war surpassed any year in the history of the Navy. As production swung into stride, shipbuilding accelerated to such an extent that ships were finished with remarkable speed. As a consequence, ships of all categories are flowing into the Fleet months ahead of schedule.

Anti-submarine vessels are even being built on the Great Lakes and inland rivers. The production, arming, equipping, and training of this type of ship is the answer to the submarine menace. As these vessels are completed and take station along the American coasts, the submarine will move to less dangerous waters.

This year many vessels of the active Fleet were remodernized. Practical lessons learned from actions afloat were applied in making the ships less vulnerable to bombs and torpedoes and their anti-aircraft batteries materially strengthened with the latest guns and mounts. Ships damaged in action returned to Navy Yards and were repaired with great speed and sent back to the Fleet.

The sound detection gear used in hunting submerged submarines came in for much attention. The field of science has exploited this system of acoustic sound gear until each month finds a better type of sound gear being put into production and furnished to the Forces afloat. Loops were devised to detect the approach of submarines into vital areas and laid to give advance warning and the location of submarines.

Mining operations by the enemy along our coasts diverted attention to the protection of ships from this menace. The British had made great strides in this direction and the cooperation from our Allies saved much time in putting gear aboard our ships that gave protection from the latest types of enemy mines.

The new secret installations to detect the approach of planes or ships at great distances were installed on board ships and at strategic shore stations to warn of the approach of the enemy. Great strides have been made along these lines. This system has contributed a great deal in the running down of enemy surface vessels and warns of the approach of planes in ample time to afford our own planes the opportunity to get up into intercepting positions.