There are four principal requirements for the successful use of torpedoes in action by destroyers:
- To design and maintain all torpedoes so that they will carry the maximum weight of explosive and run the necessary range with moderately accurate course, speed and depth every time they are fired.
- To select and gain the most favorable positions and times for firing.
- To determine correctly the sectors in which our torpedoes will have the greatest effect upon the course of the action being fought.
- To use a positive and rapid system of torpedo control to fire torpedo salvos of the full volume available.
The following characteristics are recommended for torpedoes to be carried by destroyers:
- Absolute reliability; this is of primary importance.
- Maximum weight of explosive in warhead; at least 600 pounds should be used.
- Moderate range; 10,000 yards is sufficient.
- Moderate accuracy; 500 yards deflection at 10,000 yards run is satisfactory.
- Variable speed; moderate speed at long range and high speed at short range; moderate accuracy of speed, one knot being not an excessive error.
- Suitable depth control to prevent broaching and running at excessive depths.
Of these characteristics reliability is by far the most important; circular runs, cold shots, broaching and runs at excessive depths should be unknown; our first problem is to prevent these faults rather than to develop long range and absolute accuracy of course and speed; the importance of absolute reliability cannot be too strongly stressed.
The water-tight integrity of modern ships has been so improved that capital ships will be able to withstand from three to five hits of our present torpedoes and from two to four hits will be required to sink a light cruiser. It follows that we must not only hit with torpedoes, but hit with the largest possible weight of explosive in our warheads. In the same way that guns have been increased in size so that their hits will be more effective, the explosive charge of torpedoes must be increased to the highest limit. The minimum should be 600 pounds. This should take priority over all increase in range over 10,000 yards and over all other requirements except reliability.
Moderate range is all that is necessary; 10,000 yards is sufficient for the straight run of the torpedo; more than this will encourage fire at excessive ranges and will operate to decrease the weight of explosive. It is necessary, however, that the torpedo should run every time the moderate range specified. To this end cold shots must be absolutely eliminated and any alterations to effect this should be made regardless of what radical steps may be involved. The prevention of cold shots is a problem with which we have been struggling ever since the invention of the heated air torpedo and it would appear that there are a greatly excessive number of them at present.
Exact or nearly exact accuracy in the course of the torpedo is unnecessary. A torpedo which has a lateral deflection of 500 yards at 10,000 will have an inappreciable error for a short range shot, and when fired at long range in action it has exactly as much chance of hitting an actual ship in the target as one with zero deflection. All that is necessary is that torpedoes keep within the approximate area covered by the salvo of the attack unit. On the other hand, all circular or erratic runs—before the torpedo has run its designed straight course range—must be absolutely prevented. If necessary, accuracy in the course of the torpedo must be sacrificed to obtain the necessary reliability of the vertical steering mechanism.
Moderate speed will have to be accepted for long range firing because it cannot be increased without sacrificing other more important characteristics. For short range firing, however, where a single ship is selected as the target, high speed is very important and in this case it should be obtained by reducing the range. All torpedoes for destroyers should be designed so they can be fired at two and preferably three speeds, the setting to be made without withdrawing the torpedo from the tubes. A suggested combination of speeds would be 28 knots for 10,000 yards range, 35 for 5,000 yards and 42 for 2,000 yards. No originality is claimed for this idea, which is one of the usual characteristics of the Whitehead torpedo.
The depth control must be absolutely reliable. The Germans lost about five hits on British capital ships at Jutland because their torpedoes ran at excessive depths. On the other hand, the broaching of even one torpedo may allow the target to detect the presence of an entire salvo of thirty-six torpedoes. It is unnecessary for torpedoes to run at exactly their set depths, but four feet should be the greatest allowable variation.
The subject of firing positions has been handled in an official publication and it is necessary here to emphasize only the point that torpedo hits decrease in battle very rapidly as the run of the torpedoes increases and that it is impossible to be too close to the target when firing. It is also necessary that attack units which do not fire at point blank range should gain firing positions so their torpedoes will converge on the target from different directions. This prevents the target from maneuvering clear of all salvos and also reduces the chances of individual ships dodging torpedoes sighted close aboard.
The selection of the proper time to fire is as important, if not more important, than the firing position. It must be determined from an estimate of the tactical situation made sufficiently in advance so that the attack unit will be in the proper position and ready to fire at the proper time. The perfect timing of the German destroyer attacks at Jutland shows that they had given much attention to this most important problem.
The selection of the firing positions, the determination of the methods of approach to these positions and the time to fire arc problems which can best be studied on the game board; they should be supplemented by tactical maneuvers.
We now come to the third requirement of torpedo fire: i.e., the determination of the sectors in which our torpedoes will have the greatest effect upon the course of the action. This subject will be treated in some detail. Many officers consider that they have only to estimate the course and speed of the target before firing and use this data on the director. Much attention has been given to methods of obtaining such data. While it is desirable to estimate the course and speed of the target before firing, it would be folly to assume that the target will oblige us by maintaining this course and speed steadily during the run of our torpedoes.
Assuming that torpedoes fired in a day action by destroyers will have an average run to the target of 5,000 yards, the duration of their run will be about five minutes. To this should be added a period of at least three minutes to cover the interval between the instant when the target’s course and speed are estimated and the firing of the middle torpedo of the salvo. Should the course and speed of the target be signaled by the attack leader, this interval might be greater. However, it may be assumed without much chance of error that there will be an interval of at least eight minutes between the time when the target’s course and speed are estimated and the time when the middle torpedo passes the target. In some cases, particularly when it is necessary to use an unfavorable track angle, this elapsed time will be much greater.
As an example of what may be expected to happen in action during a period of eight minutes a study has been made of the changes of course and speed made at Jutland by various representative units suitable for selection as torpedo targets. A table has been compiled to show the changes of course made during the action.
Name of Unit | Number of Ships | Time engaged | Number of Changes | Average Time between changes | Average Changes | Change in 8 Mins. |
British Battle Fleet | 24-27 | 2 h 30 m | 17 | 8 m 48 sec | 42° | 38.4° |
German Battle Fleet | 22 | 4 h 00 m | 21 | 11 m 24 sec | 52° | 36.0° |
Battle Cruiser Fleet | 4-6 | 4 h 45 m | 28 | 10 m 12 sec | 38° | 29.6° |
Fifth Battle Squadron | 3-4 | 4 h 45 m | 40 | 7 m 06 sec | 34° | 38.4° |
German Battle Cruisers | 4-5 | 5 h 00 m | 44 | 6 m 48 sec | 49° | 57.6° |
4th Light Cr. Squadron | 5 | 2 h 42 m | 33 | 4 m 54 sec | 43° | 70.4° |
2nd Light Cr. Squadron | 4 | 4 h 45 m | 36 | 7 m 54 sec | 53° | 53.7° |
While these changes of course may appear to have been large and frequent, they were really less than may be normally expected in a future action, for the following reasons:
- During the action there were many long intervals where the forces were but lightly engaged or not engaged at all, thus allowing steadier courses to be steered.
- Very few changes were made by target units for the purpose of avoiding torpedo attacks, which are certain to be more frequent in future actions. In this table only changes of course by entire units have been entered; those made by individual ships to dodge torpedoes sighted close aboard have not been included.
- As no submarines were present no zigzagging was done and no changes of course were made to avoid submarines sighted close aboard. A few changes may have been caused by erroneous reports of submarines.
Changes of speed are not to be expected in action with nearly the same frequency as changes of course, but still must be considered as possibilities. A table has been compiled to show the changes of speed made by representative units of the Grand Fleet.
Name of Unit | Average Time between Changes | Average Amount of Change | Average Change in 8 Minutes |
British Battle Fleet | 24 minutes | 2.6 knots | .866 knots |
Battle Cruiser Fleet | 30 minutes | 2.4 knots | .640 knots |
4th Light Cr. Squadron | 9 minutes | 3.3 knots | 2.933 knots |
The German Battle Fleet made five changes of speed, but the amounts are not known. From an examination of these tables it will be evident that any torpedoes fired at above the point blank range of 600 yards will have little chance of effectiveness if the course and speed of the target as estimated before firing are used on the torpedo director. On the contrary it must be set with such a course and speed of the target as will throw the torpedo salvos into a sector where they will have the greatest effect upon the course of the action. This involves a prediction as to the most probable plan of the target commander and the maneuvers which he will use to carry his plan into effect. Where a definite prediction cannot be made, this usually requires the filling of a certain sector so as to force the commander of the target to a choice between two evils, compelling him either to accept the risk of making our torpedoes effective or to place himself in a position where other portions of our forces will have important advantages over him.
It will prove convenient to group torpedo attacks into several classes which may be defined as follows:
- Supported Attacks: In which the target ship or formation is engaged in a gunfire action with our units of equal or superior types, so it is able to devote only a part of its attention to avoiding the torpedo fire of our attack units of inferior type or types.
- Unsupported Attacks: In which the target ship or formation is not engaged in a gunfire action with our units of equal or superior types, so it is able to devote its exclusive attention to avoiding the torpedo fire of our attack units of inferior type or types.
Each of these forms of attack may be subdivided into:
- Co-ordinated Attacks: In which there are two or more of our attack units, of one or more types inferior to that of the target, making nearly simultaneous attacks from different directions on that same target ship or formation, which must divide its attention among the several attack units.
- Single Attacks: In which there is but one attack unit of a type inferior to that of the target ship or formation, which can devote its exclusive attention to this attack unit.
The following may be cited as typical examples of these forms of attack:
- Supported Co-ordinated Attack: A target formation of battleships or battle cruisers, while engaged in a gunfire action with our battleships, is attacked by several attack units of light cruisers, destroyers, submarines or torpedo planes from different directions.
- Supported Single Attacks: A target formation of light cruisers, while engaged in a gunfire action with our light cruisers or aircraft carriers is attacked by one attack unit of destroyers, submarines or torpedo planes.
- Unsupported Co-ordinated Attacks: A target formation of battle cruisers is attacked by several attack units of light cruisers, destroyers, submarines or torpedo planes from different directions.
- Unsupported Single Attacks: An aircraft carrier is attacked by one attack unit of destroyers, submarines or torpedo planes.
As the most complete tactical situation occurs during a supported co-ordinated attack, this form will be examined as an ex ample of the methods of estimating a tactical situation for the purpose of predicting the future movements of the target. The other forms of attack are similar, except that as some of our forces may be eliminated the estimate is more simple, although the tactical situation is less favorable for effective torpedo fire.
The officer whose duty it is to predict the future movements of the target must imagine himself in the position of the target commander and endeavor to view, as nearly as possible, the tactical situation through his eyes. The target commander in making his estimate must take into consideration the following units or groups of our forces:
- Our own attack unit and. if any, other similar units of the same attack group attacking the target from the same direction.
- Other distinct attack units or groups which are attacking or threatening attacks from directions different from our attack but in co-ordination with it.
- Units or groups of our forces of types superior or equal to that of the target with which gunfire actions are being carried on or are impending.
It will first be desirable to determine whether the target commander will probably eliminate any of these units or groups from his serious consideration. If the gunfire action has been temporarily suspended by the laying of a smoke screen, the target commander might consider that he could neglect for a short period 'be units with which he had previously been carrying on his gunfire action and give his exclusive attention to avoiding the torpedo fire of our attack units. On the other hand, if the gunfire action were being carried on at decisive ranges and our attack units were being successfully held off by the enemy light forces, the target commander would be justified in neglecting these attack- units for the immediate future and devoting all his effort to the gunfire action. In the same way our particular attack unit might be concealed by smoke or low visibility from the target commander or he might think that its threat was so small in relation to the forces engaged that he could afford to neglect its presence. There were examples of all three such cases at Jutland.
After eliminating such units or groups as do not merit serious consideration, it will next be desirable to determine if there is one plan which the target commander can carry out which will be advantageous to him as regards his dealings with all our remaining groups or units. If there is such a plan, it should be easy to estimate what it will be. In this case, however, our torpedo fire will usually be ineffective, and it should he withheld until a later time unless we are in a particularly favorable position or there is some special reason for firing. An excellent example of such a tactical situation will be noted at Jutland between 4:30 and 4:40 p.m., when Admiral Hipper, by four simultaneous changes of course, disengaged his battle cruisers from an overwhelming force of battleships and battle cruisers and at the same time avoided a well executed torpedo attack. The torpedo hit received by the Seydlitz at 4:57 was made by a destroyer which temporarily withheld its fire until the tactical situation had changed.
We now arrive, by the process of elimination, to the usual situation where the target commander must devote his serious consideration to two or more units or groups and is unable to carry out a plan which is favorable as regards all of them. We must now endeavor to estimate the relative weight which the target commander in his estimate of the situation will give to each of our distinct units or groups. This must be determined from:
- The actual tactical situation.
- The doctrine of the enemy fleet as applicable to the present situation.
- The known characteristics and opinions of the target commander, particularly with regard to the effectiveness of torpedoes in action.
We now arrive at two classes of tactical situations:
- Those in which the weights assigned to the various units or groups of our forces arc approximately equal and there is no outstanding unit or group to which the target commander will assign a position of primary importance.
- Those in which there is a unit or group of our forces to which it is reasonably certain the target commander will give a primary status.
In the first case, there are two plans open to the target commander:
- A compromise plan which will have both advantages and disadvantages as regards two or more of our units or groups.
- A definite plan which will he distinctly advantageous to him as regards one or more of our units or groups and disadvantageous as regards the others. This opens up the possibilities of two or more plans, in each of which a different unit or group of our forces is assigned the leading status.
Therefore, in the first case, we will be unable to decide whether the enemy will adopt a compromise plan or one of a number of definite plans, and we can do no more than guess at the one which he will adopt. Under these conditions, it will be most desirable to assume that the enemy will neglect our threat and carry through the plan which will be most advantageous as regards his operations against the other units or groups of our forces. This assumption has the following advantages for us:
- If our assumption is correct, we will succeed in putting our torpedoes through the target; if it is not correct, while the target commander will succeed in avoiding our torpedoes, he will be compelled to accept disadvantages of gun or torpedo fire, or both, as regards our other units or groups. Thus we force him to a choice of evils.
- Furthermore, if our assumption is correct, our torpedoes will not only pass through the target, but will probably be effective against big ships, as the target commander will have taken no precautions to nullify their effect. If our assumption proves incorrect, then we have lost little, because if the enemy devotes his exclusive attention to avoiding our torpedoes, there is little chance that they will either pass through the target formation or be effective against the target ships.
- The target commander uses a compromise plan, not only will he suffer disadvantages as regards our other units or groups, but there is a possibility that part of our salvo will be effective.
In the second case: i.e., that in which all the evidence points to the target commander giving his primary consideration to a particular unit or group of our forces, it will be advisable to assume that he will make use of the plan which will be most favorable to him as regards that unit or group, neglecting all our other units or groups.
It is believed that these very general principles will provide a reasonably simple means of estimating the probable plan of the target commander, but each situation must be judged strictly on its merits. Having decided on the plan of the target commander, or having assumed a plan where decision would be impracticable, we must now endeavor to predict the maneuvers which he will most probably make to carry it out. Here again we must be familiar with the standard procedure of the enemy, as shown in his past actions and thus far in the present one. In case none of this information is applicable to the present tactical situation, we can only base our decision as to his most suitable maneuvers upon our general knowledge of tactics.
After having made definite decisions or assumptions as to the maneuvers which will most probably be used by the enemy, we can then determine the approximate areas which should be filled by our torpedo salvos. If we are confident of the correctness of our estimate of the enemy’s intentions and arc willing to gamble on it, we can put all our torpedoes in a narrow sector, so as to increase the effectiveness of our salvos, provided they pass through the enemy’s line. On the other hand, if there is great doubt as to the maneuvers of the enemy, we can play a safer game and be content with a lesser effectiveness by widening the sector to be covered.
To obtain the best results from torpedo fire, all salvos fired by a single attack unit should be co-ordinated by the unit commander, who should designate the area to be covered by the torpedoes. This sector can best be defined by signaling the course and speed of the target and the spread, if any, which is to be used by the entire unit. The course and speed of the target will usually have no relation to the course and speed of the target before firing, but will be determined by the predicted maneuvers of the target during the run of the torpedoes. Should it be impracticable for the unit commander to control torpedo fire by signal, commanding officers will make their own estimate of the probable maneuvers of the enemy and fire their torpedoes accordingly. In case the approach is made behind a smoke screen, it is particularly important for the unit commander to control his torpedo fire by signal, as he will be the only one having a clear view of the situation.
It will be seen that the responsibility for the success or failure of our torpedo fire in action rests to a very great extent upon the officer who decides upon the sector to be filled with our torpedoes, it is of particular importance to have on each attack leader an officer specially trained for this duty, and an extra officer should be allowed for this purpose.
In general, the problems involved in the determination of the future maneuvers of the target may be divided into two categories:
- The collection of information.
- The estimate, based on this information.
Information may be collected in the following ways:
- By advance study of the characteristics of enemy ships and of enemy tactical procedure. This is necessary for recognizing the types and classes of vessels in the enemy fleet, for determining the target angle, the maximum speed when steaming singly and in formation, the depth setting of our torpedoes, and for predicting the probable maneuvers of the enemy.
- By viewing the situation. In this way, if visibility conditions are favorable, we may obtain an idea as to the approximate dispositions and strength of our own and enemy forces within striking distance of the target, the general course of the action, the course and speed of the target prior to firing and the target angle. Unfortunately, due to his comparatively low position on small vessels, the torpedo control officer will have a distorted picture of the action, and smoke will probably shut out at least a part of the battlefield.
- By receiving and intercepting dispatches and signals from our own and enemy forces. It will often be possible to obtain from other portions of our forces, particularly aircraft, valuable information as to the present dispositions of our own and enemy forces and as to the plans and projected movements of the former. There is also the possibility that we may be able to obtain information regarding the plans and projected maneuvers of the target and other enemy forces by deciphering radio dispatches and reading tactical signals. Jutland showed what could be accomplished in deciphering enemy radio dispatches, but of course this could only be done on large ships where cipher experts are available. On the other hand, there is no reason why small ships should not be able to gain information from enemy signals, particularly if the same one is made several times and the corresponding maneuver witnessed. Even the knowledge that a tactical signal is flying is important, for we have the opportunity to wait until it is executed and the maneuver completed before firing; then we will be certain that no additional maneuver will be made for the first part of the run of the torpedoes, whereas, had we fired with the signal up, such a maneuver would have been probable.
- By plotting or using instruments graphically to solve torpedo problems. On small ships not much can be expected in the way of plotting, and consecutive ranges and bearings of certain ships should not be attempted. However, single ranges and bearings of various units of our own and the enemy forces may give the torpedo control officer a more correct idea of the situation than he can obtain by viewing it from a low position. On small vessels instruments for solving torpedo problems, notably those devised by Lieutenant Commander W. A. Lee, may be used to great advantage.
The greater part of the training of the torpedo control officer in his duty of obtaining the information upon which to base his estimate must be obtained at sea. Opportunities are constantly afforded in the routine exercises at sea and in gunnery and torpedo training. Tactical maneuvers, however, are required for giving him the necessary advanced training.
In order for the torpedo control officer to obtain the necessary information, it is evident that he should be located in a high position where he is undisturbed by other activities and from which he has all-round vision without moving. His station should be equipped with a fixed high power telescope and have voice tubes leading to the bridge and radio room. A good range finder should be available for the use of the torpedo control party and a signalman should be assigned to it for the special duty of watching the target formation for visual signals. After having collected the information, the second part of the torpedo control officer’s duty is to make the estimate of the probable maneuvers of the target formation during the run of the torpedoes.
The tactical game board affords the best training in making this estimate, for all the information is available from a study of the forces on the board and the correctness of the estimate can be determined from the future movements of the target formation and the probable number of bits which would have been made. Such training is absolutely essential for torpedo control officers.
Use could be made of the series of plates of the Battle of Jutland issued by the War College for additional training. Each of the plates of the day action should be studied in detail and the maneuvers of each unit suitable for selection as a torpedo target should be predicted for a period of eight minutes. Then by turning to the succeeding plates the accuracy of the predictions may be determined. During such a study it will become noticeable that the British battle cruisers used a doctrine erf successive changes of course while the Germans used simultaneous changes. If the standard procedure of the enemy may be determined before or during an action, this will be of great assistance to the torpedo control officer in making his estimate.
The advanced training in making the estimate must be obtained in tactical maneuvers at sea. All such maneuvers should be carefully plotted and placed on the game board, together with the sectors covered by the torpedo salvos, so that the accuracy of the torpedo control officers in estimating the maneuvers of the target can be determined.
In the course of our discussion we have considered only the case of the supported co-ordinated attack. The other forms of attack will require similar estimates, but as there will be fewer forces involved, the estimate will be simpler to make. On the other hand, however, in these cases it will be more difficult to hit with torpedoes, because the more of our forces there are to engage the attention of the target commander the less attention will he be able to give to the avoidance of our torpedo fire.
It now remains only to mention the fourth requirement for successful torpedo fire: i.e., a positive and rapid system of control for firing the full volume of our torpedoes. It is evident that even though we have a perfect torpedo and know exactly how to use it in action with the most effect, we cannot obtain results unless we have the proper torpedo control equipment, which particularly includes the means of transmitting the firing orders and information to the torpedo tubes. Due to the confidential nature of this subject, its details cannot be discussed here, but all destroyer officers will know our present status in this matter and recognize the importance of having suitable torpedo control stations and equipment on the same scale as that already in use for gun control. This is of special importance for the destroyers of the attack groups of the battle fleet, where there is no question but that the torpedo should have priority over the gun and the most desirable position should be used for the torpedo control station instead of for gun control.
In conclusion, it is desired again to emphasize the following primary requirements of successful torpedo fire:
- The development of an absolutely reliable torpedo carrying the maximum weight of explosive.
- The study of tactics so as to determine the position and time for firing torpedoes and the methods to bring the attack units into this position at the proper time.
- The further study of tactics to develop accuracy in the prediction of the projected maneuvers of the target in battle during the run of the torpedoes.
- The installation of suitable torpedo control equipment in a distinct torpedo control station which will permit the torpedo control officer and party to work under the most favorable conditions in battle and have a positive and rapid system of control over the torpedo battery.