The popular conception of a modern navy is an aggregation of fighting vessels varying from the small torpedo boat to the great battle ship. The speed, armament and general efficiency of these vessels have the attention of the general public, and their personnel is a matter of keen interest and deserved pride, in our own country at all events. Beyond these points the general interest and information rapidly wane, which is but natural and to be expected. How a ship is built, equipped, and kept efficient is so largely a matter of technicalities that it is outside the interest of the public at large, and not the least reason for this lack of interest in technicalities, in the United States, at least, is that the history of our navy from its beginning to the present time is a record of unbroken successes in the various emergencies through which it has passed. There have been times when its ships have become antiquated in type and reduced in numbers almost to obliteration, but the spirit, tenacity and ability of its personnel have never failed or lagged even under the greatest discouragement.
When comparisons are made of navies they are generally based on tonnage displacements, armaments and types of vessels without regard to the means of maintaining their efficiency and effectiveness at all times and under all conditions.
The most efficient fighting ship is the one that is in the most perfect condition as to hull, machinery, armament and equipment; which has fuel bunkers full, a complete supply of ammunition, and whose officers and men are well trained and disciplined and in the best of health and spirits. How long can a ship remain in this perfect condition? The fuel supply begins to diminish from the time of putting to sea; if it is in time of peace the trip is so laid out that fuel can be renewed at certain ports of supply, but in time of war this one question of fuel alone may greatly limit the radius of action. If at rest the bottom is becoming foul and deteriorating, and the ship is constantly becoming less capable of making speed at any time. The stress of a chase or the severity of an engagement may render repairs to machinery very necessary, or a fresh supply of ammunition imperative, even in the event of a ship not having suffered other injury or loss. The strain, both mental and physical, is much greater on officers and men in time of war and without estimating on the possibilities of epidemics, it is likely that the personnel of a war vessel may need partial renewal more frequently during war than in peace.
It is not necessary to follow this line farther to show how dependent a navy is upon its dock yards and supply stations, not only for its efficiency but for its continued existence, and more especially in war than in peace.
The policy of the United States has always been defensive, particularly of its own rights and broadly of sound principles. While it remained a continental country its dock yards and stations must necessarily be on the continent, and from them all naval defense would start. The acquirement of insular possessions renders the continental dock yards and stations, alone, insufficient for naval defense, for no extensive operation or supervision can be conducted without a convenient base of repair and supply.
The extent of naval operations depends upon how long a ship may remain away from a base of supply and repair and still be efficient, or how far it may leave such base with reasonable chance of return. When active defense becomes necessary the regular bases of a navy may prove inconveniently remote for its operation to the best advantage. It then becomes desirable to establish a base at or near the scene of operations, but this may be in hostile territory or in a country where a permanent base would be valueless when the emergency had passed; moreover, an efficient permanent base requires years in building, as its basis is the dry dock, which is the one thing which cannot be extemporized, and without which no ship can be maintained in perfect condition.
In defensive naval warfare we cannot choose the points where we will be attacked, but we can safely predict that they will be where we are the least defended, and where our ships are the most likely to be met in the least state of efficiency. Such points are matters of common knowledge to the world, and whether their attack result in the defeat of a fleet or the destruction of a city the result is equally disastrous.
These conditions and possibilities suggest a movable base which can be taken to the scene of operations, and which should supply all of the essentials of a completely fitted base of the permanent type. Even the movable base does not supply all that is desirable for modern operations, for, as far as possible, the greatest efficiency is secured when necessities are taken to the fighting ship and it is not compelled to go for them. To secure this last desirable condition, the movable base should consist of units each of which, where possible, should farther constitute a flying sub-base which can search employment when not operating directly with the movable base, or when more urgently needed elsewhere.
FLOATING DRY DOCKS.
The essential element of a movable or temporary base exists in the floating dry dock, but until Spain sent such a dock to Havana, it may be said to have been a dormant military idea. That dock was intended for war ships, and the existing conditions at the time the dock was installed rendered the fact of unusual significance. The failure of the dock to pass its tests, and its various mishaps of accidental sinking and failure of machinery, partly through mismanagement and partly from too economical designing, tended to mask the true value of these structures, and obscured the importance of the manoeuvre of towing the dock from England to Cuba. This unfortunate dock was finally broken almost completely in two while being self-docked, and had this accident happened before the United States had taken the initiative with this class of structures for war purposes, it is difficult to predict how many years might have elapsed before a complete movable base would have been possible.
The United States was the first country to provide itself with a thoroughly modern floating dry dock suitable for military purposes, but was so closely followed by Great Britain with her new Bermuda floating dock that no great advance can be claimed in inaugurating a new possibility in naval warfare. Neither was the full military possibility of the American dock generally recognized when it was provided, as it was intended for installation in the Mississippi River at New Orleans where land dry docks had been considered practically impossible of construction, and thus the primary cause of its existence was topographical and not strategic.
The full significance of a military floating dock was first realized when the United States recently provided for such a structure for the Philippines. The New Orleans dock had just proved a successful experiment; it was of British design but built under a general specification of the Bureau of Yards and Docks, and while it performed much more than was required, not the least important thing learned during its construction and testing was that more should be demanded of these structures than had hitherto been the case. At this time the establishment of a naval base in the Philippines was one of the most urgent problems confronting the nation; one demanding the utmost care and not possible of quick execution, even were the solution readily apparent. The floating dock happily relieved the situation; the essential of a naval base was provided, and if one location did not prove satisfactory another could be found. Profiting by the experience gained with the New Orleans dock the requirements for the Philippine structure have been made more exacting and comprehensive than has ever been the case with any previous floating dock in the world. The requirements demanded of it are so far in advance of those demanded of the New Orleans dock that its success is assured in advance. Structures of this class have been towed across the Atlantic Ocean and the North Sea and their seaworthiness has been fully demonstrated, but the towing of the Philippine dock half way around the world will be the final demonstration of the mobility of these structures, and will be a naval manoeuvre of the greatest interest to all nations.
Considered as the basis of a movable base, the possibilities of the floating dry dock are yet far from being fully developed. By increasing the width of its side walls extensive shops may be installed on the dock itself and other desirable installations may be made, while the increase in side wall width also permits the installation of traveling cranes capable of handling the heaviest machinery and armament.
Repairs and preservation of war ships are too often considered from a peace basis alone; from such a basis the land dry dock has many attractions, but as a war tool the advantage is with the floating dock. We are rapidly nearing the draft of ships which requires a depth for land dry docks that renders them enormously costly, very difficult and slow of construction, more liable to failure from increased hydrostatic pressure, and in which no excess of depth is provided for emergencies. In time of war we may expect to deal with ships that are badly listed, down by the head or stern, or at an abnormal draft from injuries, and it is in such cases that the floating dock shows its superiority. It can readily be constructed for any possible emergency draft at slight increase of cost, and can be listed and depressed by the head or stern to take in a wounded ship that it might be impossible to enter in any land dock that we have under construction or projected. Sufficient depth of water is essential for the operation of a floating dock, and in maximum cases it must be from fifty to sixty feet and should be comparatively smooth, though a strong current is not objectionable. A ship once in the dock, however, it may be towed into a sheltered position which the ship alone could never reach, as these docks only draw from sixteen to eighteen feet with their full load.
In the development of the military floating dock it is entirely practicable to equip them with a hydraulic dredging apparatus with which they can make their required depth of water without seeking it, and by arranging the dock pumps to discharge under the bottom of the dock in suitable places, the dredged site can be constantly maintained, or even made without other aid, in a soft or sandy bottom. The hydraulic dredging apparatus installed on a floating dock may be of farther strategic value for improving the entrance to harbors, or even obstructing them, if advisable.
As the basis of a movable base the floating dry dock is the unit which will give the most anxiety when moved during time of war. Its progress in towing from point to point must be slow, and unless strongly convoyed it invites capture or destruction by an enemy. This danger may be reduced to a minimum by using the dock composed of complete and independent sections which are strongly connected into one unit when in use, but which are separable into sections for self-docking and other purposes; when separated into sections each one may be towed by a different route and at a different time. If the number of sections is in excess of the maximum requirements, the loss or capture of one is not serious, and the gain to an enemy is practically nothing. In any event the towing of a dry dock can be made an invitation to battle that, if accepted, might culminate a naval war.
REPAIR SHIPS.
Another unit of the movable base is the repair ship. The equipment of the floating dry dock as a repair shop in no way curtails the usefulness of the repair ship, but rather increases its radius of useful action by leaving it free to attend to such ships as do not need actual docking.
The repair ship should be as completely fitted out for a repair shop as it is possible to so do with a floating structure, and the equipment may readily be carried to shears, punches, and steam hammers. A varied assortment of repair material should be carried in abundance, and artisans should largely constitute the crew.
The duty of the repair ship is to put in order the vessel that does not actually need to be dry docked for relief, and the majority of external and internal injuries above the water line may be made good by this ship. When the temporary base has been established the repair ship goes from vessel to vessel needing its services, transferring artisans and materials for such repairs as can be made on board the injured ship itself, and in the meantime, fabricating such material as requires its more extensive equipment and preparing it for transfer and installation at such time as it becomes ready.
These are the duties of the repair ship as a unit of the movable base, but it should still farther constitute a flying sub-base capable of searching a cruising ground for vessels in need of its services, and to this end should have speed equal to any vessel of the fleet. Such speed not only insures prompt service in time of need, but enables the repair ship to accompany a fleet without decreasing the efficiency, and permits it to cruise in time of war with the least danger of capture.
If a vessel is found by the repair ship to be in too serious a condition to be promptly and effectively benefited by its services, it may serve to tow the disabled vessel to the floating dry dock where repairs can be made to better advantage, and the repair ship thus left free to carry its services where they will be of greater advantage.
COLLIERS.
No matter how formidable or efficient a fighting ship may be it must have fuel in abundance for the best results, and if a certain and ample supply is always sure, its possible radius of action is unlimited. Without fuel, defense is not only weakened, but attack is impossible. Stationary coaling stations do not insure a constant and unlimited supply of fuel, nor do ordinary colliers in time of war. The ordinary collier may form an important unit of the movable base for the supply of such ships as may visit it, and may well be employed in coaling ships which are in the floating dock or are receiving the attention of the repair ship, but considered as sub-bases they fail in efficiency. As a sub-base the collier should have speed equal to the fleet, that it may not retard the same, may quickly join it, or may evade pursuit and capture, and its fuel carrying capacity should be very great. Having these qualities it is still essential that the collier should be able to transfer fuel in any condition of sea or weather, to become in any manner an ideal adjunct to a fleet. The transference of coal at sea is as yet an imperfectly solved problem. Sufficient experiments have been made to demonstrate that coal can be transferred from a collier to a war ship at sea when the latter is towing the collier, and a trolley system has been rigged between the masts of the two vessels.
The transference, however, becomes more slow and difficult as conditions of sea and weather become worse, and as considerable speed of towing is necessary and much sea room required, conditions will be reached when more coal is burned in the operation than will be transferred, or a ship will be obliged to abandon an important strategic position which may never be regained. A collier of the capacity desirable for extensive and distant operations could not well be towed by a moderate sized war ship, nor a collier without masts be used with this method, so that its usefulness and possibilities are limited.
It is desirable that coal should be transferred at sea at any time and in any condition of sea or weather as rapidly as possible.
It has recently been proposed to transfer coal at sea with the war ship and collier alongside of each other and prevented from colliding by forcing strong jets of water towards each other from different points below the water line. The proposal is attractive, and, if its expectations are realized, much more than the transference of coal at sea will be solved. Fitted with such an appliance the repair ship would be enabled to operate alongside other ships under conditions otherwise impossible, as would also the other units of the movable base, if so fitted, to many or most of which the present trolley system of transference would be of little or no use under any conditions.
MAGAZINE AND EQUIPMENT SHIPS.
No modern naval war has witnessed the contingency of a vessel or fleet with exhausted ammunition and no supply at hand. It has seen operations against shore batteries and forts curtailed lest such a condition exist, and it has seen steel projectiles used against fortifications when cast iron would have been more economical and suitable. Although exhausted ammunition has not yet been recorded, it is still a highly possible contingency in a modern naval war. Rapid successive engagements may not be possible of avoidance when on the purely defensive, and successive victories may end in defeat and destruction when ammunition fails. Years of peace are apt to cloud our sight to this contingency. Ordinarily the deterioration of ammunition from age is our greatest concern, and target practice gives no idea of the exhaustive hail of small calibre shot that may be required to meet a well-directed and determined attack of torpedo craft. The question of coal supply we can never avoid, but the question of exhausted ammunition when far from a base, we have yet to face. We may hope to secure coal by some means when far from a base, but available ammunition will never be captured, confiscated or bought, under like conditions.
This possible condition of depleted or exhausted ammunition of any or all calibres suggests a magazine ship as an important unit of a movable base, and as a still more important naval adjunct, if of sufficient speed and capacity to become a flying sub-base. As the ammunition should be stowed below the water line, this vessel may at the same time become an equipment ship carrying such equipment stores above the water line as are most essential and most likely to need renewal.
RECRUITING AND HOSPITAL SHIPS.
As a badly disabled man is of no value as a working unit on a fighting ship, it is highly important, both for his own comfort and the good of the ship, that he be removed as soon as possible and his place supplied with an able bodied man.
As men ready and fit for service go to the fleet and the ill and disabled come from it, recruiting and hospital service can be combined to advantage on the same ship. Not all humanitarians will agree to this proposition, as it will deprive the ship of the immunity enjoyed by a purely red-cross institution, but if the ship be given great speed it may readily avoid capture and will the sooner bring the ill and disabled to greater comfort and the sooner supply their vacancies in the fleet.
In emergency and particularly in the early stages of defensive operations, the recruiting and hospital ship may become of the greatest value for use as a transport. The prompt landing of a few hundred men before strong opposition from sea or land can be offered, may secure the rapid and safe establishment of a movable base, or the successful holding of other important positions, which many times the same number of men could not effect after a slight delay.
The maintenance of hospital ships or of transports, alone, does not appeal to us in time of peace, therefore this class of sub-bases may ordinarily be usefully and constantly employed as training ships for landsmen, which will insure the readiness for use of these ships.
THE COMPLETE BASE.
The complete movable base consists, then, of floating dry docks, repair ships, colliers, magazine and equipment ships, and recruiting and hospital ships, to which may be added provision and refrigerating ships, and most of which may become transports to a greater or less extent in time of necessity.
With the exception of the floating dock all of these units should be given great speed and equipped with transferring devices so that they may become of the greatest possible efficiency as flying sub-bases. As there is a natural disinclination to put great value into a vessel for naval purposes which cannot fight, the subbases may be lightly armed with three and four inch calibres and smaller rapid fire and automatic guns, thus protecting them to some extent, and rendering them most formidable commerce destroyers.
There is also farther reason for lightly arming these vessels. The movable base will be established as near the scene of operations as possible, perhaps in a hostile country itself. It is desirable to employ as few vessels of the fleet as possible in the protection of the base, and to this end more or less of the guns from the sub-bases may be landed and emplaced in shore batteries for protection both from land and seaward. One of our latest lessons in naval warfare is that land batteries are hard to silence and still harder to destroy, and that in closely engaging them a ship takes undue risk. With concrete and deflecting armor and the unlimited space afforded on shore, it seems a safe assertion to say that in a few days a battery could be constructed that the heaviest guns afloat could not destroy. Deflecting armor and cement for concrete may readily be carried in abundance on the floating dock, as might also land and floating pile drivers for farther aid in fortification work. If desired, a few larger calibre guns could be carried in storage on the dock for rendering shore batteries still more formidable. With the assistance of torpedoes, sub-marines, and monitors, in conjunction with the shore batteries, the defense of the movable base could be made very formidable, and the cruising fleet would be left largely free for independent operations.
In the defense of the movable base it is important to note that its most essential unit, the floating dock, can be rendered nearly invulnerable by almost complete submergence. No more than a couple of feet of the side walls need be left above the water line, and should these be pierced, the dock can be readily and quickly raised a little higher and the shot holes stopped with plank and oakum. The accidental sinking of a floating dock may be prevented by placing a watertight deck in the side walls at a suitable height; in a military dock such a deck is advisable for the farther reason that docking operations may be hastened by eliminating the necessity of skillful management when reaching deep submergence.
Having the floating dry-dock as the essential unit, it is not absolutely necessary that the others should be the high speed, lightly armed vessels that are herein advocated, in order to constitute a very efficient movable base for operations in one place without extended scope. Merchant vessels can be taken in emergency and converted to as great advantage as possible, and convoyed to the site of the base while the dock is being towed. The floating dock cannot, however, be left to be secured when the emergency occurs. Ordinarily it can be built in two years; under stress the usual types can be built in a year, and the sectional type can be built in six months by constructing the sections at different ship yards.
AVAILABLE FLOATING DOCKS IN THE WORLD.
The United States has a modern military floating dock at New Orleans of fifteen thousand tons capacity, but not equal to the heaviest ships it is building. It has a ten thousand ton dock at Pensacola purchased from Spain, and of doubtful value for a movable base. In two years it will have in the Philippines the most complete military dock of modern times, of sixteen thousand tons capacity and equal to the heaviest ships it is building.
Great Britain has recently installed at Bermuda a floating dock of the same type as that at New Orleans, of nearly sixteen thousand tons capacity.
Austria is building a floating dock of fifteen thousand tons capacity for the naval station at Pola.
Spain has a new floating dock in the Mediterranean of twelve thousand tons capacity.
In Germany there are commercial floating docks that are available for military operations. Four at Hamburg, of which one has a capacity of seventeen thousand five hundred tons, one a capacity of sixteen thousand tons, and the other two of lesser capacity. At Stettin there is a German dock of eleven thousand tons capacity.
While the docks mentioned are, mostly very able and efficient, none of them have reached the state of development desirable in the basis of a movable base.
COMPOSITION OF BASE.
A complete and efficient movable base will consist of one floating dry dock, two repair ships, four colliers, two magazine and equipment ships, and two recruiting and hospital ships; the ships to be of the high speed and lightly armed type called flying subbases. For greatest safety in assembling at a selected location, transference to another locality, or general dispersal in emergency, the floating dock should consist of the sectional type in four sections, any three of which should be capable of lifting the heaviest battle ship or the longest cruiser.
The location of a temporary base having been selected, each section of the dock is taken in tow by one or more of the ship units and the base is proceeded to as expeditiously as possible. It has been demonstrated that a floating dock can be towed at an average rate of one hundred miles per day, and with the sectional type towed in sections by the powerful sub-bases, a greater speed might easily be reached. The arrival of three sections of the dock at the base is practically certain under any circumstances, especially if convoyed by war ships, and the arrival of all sections is almost sure, in which case the fourth section is available for the docking of tugs, torpedo boats, and other small craft. The movement of this base may be made as secret as possible, the various units departing from different permanent stations at various times and by various routes, or it may be made openly and advertised to the world, as circumstances may indicate.
When a movable base has been established in a hostile territory and war has fairly begun, its removal or dispersal will be more difficult of accomplishment than its assembling. The flying sub-bases may be able to care for themselves, but the slow moving dock is less fortunate. A dock may, of course, be quickly destroyed in extremity and need never be captured, but destruction is an undesirable event. Here again the sectional dock offers the greatest possibilities. It may be moved, one section at a time, in the face of possible detection and opposition, as the capture of one section may well be risked, for it means no material benefit to the captor.
CONSTANT USE.
The complete movable base will never be realized if it is to be purely a war luxury, and if reserved for that it might be of doubtful effectiveness when needed. Its units should be in constant use in order that we may be familiar with their handling and that they may be in a known state of efficiency.
There is plenty of use for all the floating dry docks we may build, and as a peace tool they have many advantages over the land dock. When a new permanent base has been selected, a floating dock can be towed there and we are at once ready for the most important operation that is performed on a repair station. By taking a repair ship with it we have at once an effective shop, if the dock is not already fitted as such.
The selection of a site for a land dock on a new station is not a matter to be quickly or lightly disposed of to the best advantage, and the floating dock gives plenty of time for due consideration of the matter. Should the site selected for a new station prove undesirable or a more practicable one be found, there is far less to be abandoned if we have a floating dock that can be towed elsewhere.
For cleaning, painting and light repairs, the floating dock is much more desirable than the land dock as it brings the ship well above the water surface into light and air where operations can be conducted with the greatest facility and effectiveness. As a ship has been cut in two, pulled apart thirty feet and lengthened in the center on a floating dock, there remains no doubt about what can be done on them in the way of heavy repairs.
The docking of ships is at present confined to one small class of officers, but if floating docks are to be of any importance in future naval strategy, their use and operation should be familiar to every line officer, and is next in importance to a knowledge of steam engineering.
The use and operation of a floating dry dock is not complicated. When placed in the axis of a current the entering of a ship is greatly facilitated, its centering is an easy matter, and with our system of docking keels giving three lines of support on the bottom, its proper landing is very simple. Without other knowledge of the dock, if pumping is begun at the center compartments and continued towards the ends until the ship is out of water, no injurious strains will be caused whose development would not be perfectly apparent to the eye in time to stop. There is less chance of injury in this class of docking, as two elastic and floating structures are coming in contact instead of an elastic and a fixed and rigid one.
From a strategic point it is important that a standard type of dock be selected as soon as one can be determined on, so that when the officer has become familiar with one he will understand all.
The constant use of floating dry docks can be assured, and the next consideration is the repair ship. It has been mentioned how these ships can be of value in founding a new station, and they would be of farther value as a constant adjunct to a squadron in foreign waters or during manoeuvres. When a ship is injured at a distance from a repair station prompt aid may mean its salvation.
Not the least valuable use of the repair ship in time of peace would be as a training ship for naval artisans. The training of a landsman to a seafaring man of ability, whether he be gun pointer, machinist, electrician, or quartermaster, is a matter requiring care and consideration, and we have demonstrated that it can best be commenced on training ships.
The constant use of colliers in time of peace needs little discussion. At present we must, perforce, supply our fixed coaling stations from mercantile colliers on account of lack of naval colliers. Coaling at sea we only attempt as a manoeuvre on account of its present difficulties, and at times in foreign countries we may pay large prices for inferior fuel. Much of this could be remedied with a few suitable and well equipped colliers of large capacity, and the service should not rest until some quick and certain method has been found for coaling ships at sea.
It has already been mentioned how the recruiting and hospital ship may ordinarily be used as a training ship, and the same may be said for the use of the magazine and equipment ship. We are just emerging from the period when we had added fighting ships to our navy until we had not only more than we could competently dock, but had many that we could not dock at all without civil aid, and at one time without foreign aid.
We are now entering, if we are not already in, the period when we will not have enough training ships to supply our squadrons with suitably broken in landsmen who have had a chance to acquire a taste for the sea in some comfort and under conditions that would make them of the most value.
Aside from its value as a training ship, the presence of a magazine and equipment ship with a squadron, whose supply of ammunition would thus be greatly increased, would greatly augment its military value.
As training ships, alone, there seems to be sufficient reason for the existence of the flying sub-bases.
STRATEGIC VALUE.
The movable base suggests, first and last, distant or foreign operations, but considered from a purely defensive standpoint, it has a much more important value to the navy.
Our naval bases on the continent were established many years ago in the time of wooden sailing ships and short range cast iron guns. When established they were geographically unassailable, and strategically, fairly so for the times and circumstances. With few exceptions, they are no longer unassailable. Were they all impregnable, they are too few and too poorly located for a satisfactory naval defense of our extensive coasts.
When our land dry docks, under construction and projected, are all finished our docking facilities, considered from a defensive war basis, will still be greatly inadequate to our needs.
By placing a thoroughly developed military floating dock at each of our naval bases, we may in time of threatened danger double our available bases on the coast by towing the docks to various points of vantage, or in the last extremity, if forced to retreat up our rivers and bays, we may take our floating docks with us and establish movable bases that will the sooner enable us to again reach our coasts.