One of the vexed questions of the day within the Navy is that of seamanship; i.e. the relation of past seamanship to future seamanship. That experience with the new ships will settle the question satisfactorily is highly probable; but the more consideration we give the subject in advance, the sooner will we reach settled convictions through experience. At present there is an abundance of positive and conflicting condemnation of that which exists, which is equivalent to saying that there is a lack of conclusion as to what shall take its place. Even accomplished officers sometimes condemn with an exaggeration which must be accepted as a proof of earnestness rather than a precise measure of belief For example, some assert that our standard work on seamanship is antiquated and should be discontinued in the course of study at the Naval Academy, not that parts of it should be discarded. Yet the last edition of that work was published in 1883, and embraces immutable principles of seamanship, in addition to sailing evolutions, and details of management and equipment not strictly applicable to the new and projected steel vessels.
But there are counter opinions and influences quite as strong, if not as assertive, tending to maintain unduly the old order of things because of its supposed effect in moulding officers and men to the character of the ideal seaman. This extreme opposition of opinion may do much harm outside the service, and within the service likewise; on the one side, by depreciating matters of continued importance, and inducing a cessation of effort on board vessels not of the latest type; and on the other, by retarding development on lines made plain by a vast deal of experience with modern vessels in foreign services. Between these extreme views there are others, supported by a stronger basis of observation and study, and which are likely to carry the day. To aid in the latter respect is one purpose of this paper, but I shall feel as gratified to be set right in one direction as to be approved in another. Another purpose may be stated as follows:
As head of the Department of Seamanship, Naval Tactics and Naval Construction, at the Naval Academy, consideration of our subject is forced upon me to an unusual degree, and I therefore venture to court the criticisms and suggestions, public or private, of other officers, with a view to profiting by them in my position.
The questions to be answered are: First, What shall we discard of the old seamanship? Second, what is likely to be required of us in the new order of things? Since officers are thoroughly informed with respect to the old seamanship, it is but natural that we hear far stronger opinions relative to the first question than to the second; and we find condemnation greatly preponderating over suggestion; in fact, there is very little formulated opinion in any direction. A field is therefore left open.
It must be admitted that it is difficult to circumscribe our subject, for now, more than ever, one branch of the profession merges with another; but let an effort be made by attempting a comprehensive definition of seamanship, which, if generally accepted, will make the task easier. Let us say, then, that Seamanship, as the art of the seaman, embraces a knowledge of vessels, their construction, equipment, fittings, and qualities, also their care, preservation, organization, management and direction under all circumstances. This leaves plenty of room for the inclusion of other specialties and their applications under other terms.
In attempting to establish the relation of a seaman to his art, we shall fail unless we consider the state of the art as we actually find it, and also as it tends to develop. We must value tradition as tradition, nothing more—that is, as a matter bearing on esprit du corps, not as necessarily governing practical applications of the present day. Considered in its proper relation, tradition should not be upset with violence, unless the emergency of change demands it; but when that demand is squarely made, we should be merciless towards mere sentiment. It should always be borne in mind, however, that in adopting new ideas we ought not to lose sight of that which is good and of continued application in the old.
At the outset it must be understood that I treat of naval seamanship, and that we still have in the service a number of wooden vessels of the old type, full-rigged and full-powered up to the standard of a few years ago. They are not nearly so handy under sail as the old sailing ships, but are handy to a fair degree. Under sail they will wear, tack after a fashion, heave-to, lie-to, cast, and will run free faster than many of their predecessors. In the absence of prophetic vision, let us assume that they will have ceased to exist ten years hence. Our officers are masterful on board these vessels, and for service on board them, the work on seamanship already cited remains excellent authority—unequaled published authority. Again, we have coming into life a new class of ships, not by a gradual transition from type to type, as the result of practical experience within our own service, growing with our growth, but placed in our charge with a comparative suddenness which constitutes an emergency—an emergency that we are expected to meet seriously and without flourish. It is the appearance or prospect of these vessels that renews and emphasizes the demand for a less conservative persistence in the old practices.
From what may be called the quarter-deck seaman's point of view, the essential differences between these new vessels and the old ones which remain are, diminution of sail power with increase of steam power, coal efficiency and coal endurance. The new cruisers can keep the sea for a long time, and cover a great distance at good speed under steam alone without renewing the coal supply. None of the new ships has more than two-thirds sail power, nor carries sail in excess of a bark rig, nor above topgallant sails. Some have only fore and aft sails for sail propulsion, others only fore and aft storm sails or no sails whatever. It is probable that none will have studding sails. None has head booms except the Chicago, and hers are light. The original design of the Newark provided for head booms, but that feature was abandoned. This marks a great and restrictive change in sail power, but will it be reversed and full sail power be reinstalled? Hardly, 1st, because the efficiency of any given area of sail for any given conditions remains fixed, whereas the efficiency of a ton of coal is constantly increasing with the improvements in machinery and methods. 2d, because dependence on sail in emergency is lessened by the adoption of twin-screws with independent engines. 3d, in the undamaged condition, sail is not essential to the safety of a steamer at sea. This points rather to a more universal reduction of sail area, but let it be clearly understood, not to the subversion of seamanship. Seamanship will remain as an art lifted to a much higher scientific plane, and therefore more difficult of acquirement than formerly. Its character as an art, involving prompt special judgment and high personal qualities, will suffer no abatement, as will appear in the course of this paper.
After making due allowance for the life-time of the wooden relics, shall we confine our knowledge of sails and sailing to the possibilities of a long vessel with only two-thirds sail power, bark-rigged and without head booms, or what shall we recognize of the old quarterdeck seamanship and how shall we apply it? This is the rock on which most opinions split, and is therefore the most difficult point to decide at the present time. I have been inclined to generalize with the iconoclasts, but there are strong arguments against me.
A few minutes' consideration shows that the inquiry must be answered under two heads, viz. Theory, or that which we would require an officer to know against all the possibilities of service, and Practice, or that which we would accept as worthy an expenditure of time and practical effort, as a matter of habitual routine, or otherwise, on board our vessels.
The existing officer has the theory already, and is the better for it, if he is not content to rest there. But the Naval Cadet is for the new Navy; in his future practice his dependence on sail will be in a minor degree only; his education being scientific, he will regard as a nuisance any undue sail power, which he will know is at the expense of true efficiency, for displacement tonnage, usurped by one quality, must be sacrificed by another. Having tried to show that I have given my subject some serious consideration, opinions may be advanced.
1. So long as the wooden relics remain in service, officers attached to them must be competent to fill their stations, with respect to seamanship as with all other branches; that is, line officers must be able to sail them as sailing ships if necessary, as in the case of engines disabled.
2. Whatever the rig of new vessel to which a line officer may be ordered, he must be able to utilize her sail power, in whole or in part, to all possible advantage, and from the moment that he sets his foot on board.
In respect to the theoretical knowledge of seamanship involved, these two assertions are not so widely separated as some officers seem to imagine. Any officer who is competent to take the deck of a square-rigged sailing vessel, or, which amounts to the same thing, one of our relics under sail, is competent for that duty on board all of the new war vessels, whatever their rigs, because sail management of the old type is fundamental for the new types. But an officer may be competent in the same sense on board some of the new vessels, and yet be unfit for service on board others, or on board a ship-rigged vessel. I am inclined to believe, therefore, that in demanding without qualification that we shall stop teaching the working of sailing ships, officers are going farther than they intend, because compliance with their demand would force us to abandon the rational method of teaching by fundamental principles, and compel us to adopt the less comprehensive one of special cases. By the former, we reduce the study to its smallest compass by covering all applications in a single existing type and thus prepare in advance for all types; by the latter, we must await the appearance of special types in order to prepare many officers for service on board them. It seems clear to my mind that to be generally useful hereafter, young officers must proceed from fundamental principles in all branches, seamanship being no exception. With the multiplication of types and the prospect of greatly diversified duties, a life-time of mere experience, as one will be likely to find it, will not cover the necessary ground.
Again, in teaching seamanship we should be influenced beyond the strict demands of every-day practice, as in respect to a liberal education in any other branch of study. Instruction in navigation is not confined to a knowledge of getting a ship from port to port, nor in the steam engine, to questions apart from the principles of mechanism. The education of a lawyer is not confined to the practice of modern law, nor that of a doctor to the specialties of his future practice, which would make him more or less a quack; but each is expected to become widely informed in both past and present practice, in order to amplify his scope of future study and conception. But there are practical reasons of moment for continuing to teach to young line officers the principles of management under sail alone. A naval officer's field of action includes instrumentalities and operations outside his own ship and service. We line officers, even in our character of seamen, have a wide range of duty. We serve in the Coast Survey on board sailing vessels as well as steamers; prepare sailing, coasting and harbor charts at the Hydrographic Office for all classes of vessels; also meteorological charts chiefly for sailing vessels; advise sailing-masters as to routes, weather conditions, etc.; in the Branch Hydrographic Offices, come in direct communication with sailing-masters and discuss with them questions relating to sailing vessels; are liable to be called on to decide as to the location of lighthouses, lightships, buoys and beacons, which involves a knowledge of the practice of sailing vessels. We may at any time be ordered to serve on boards to investigate collisions involving sailing vessels. We must be ready to predict or to prescribe the routes of sailing vessels, or to convoy them in time of war. To convoy them we must comprehend their limitations, in order to give them every advantage. Our immense coasting trade looks to us for protection. We must avoid collision with sailing vessels by day and by night: they have the right of way, and we must be able to prejudge their maneuvers, which, at night, is sometimes possible only to a sailor. Our nautical world is peopled to no small degree by the seamen of sailing vessels, amongst whom our influence is slowly but constantly extending, and with whom we have a common phraseology. In time of war it is the sailing vessel which will fall the easiest prize, and the charge of which will be assigned to junior officers. Finally, if we are to read critically the naval history of our own and other countries, and investigate the tactics of great naval battles of the past, we must understand, at least in a general way, the common evolutions of sailing ships.
More might be said to the point, but enough has been said, if it has been shown that there is still some reason in teaching the principles of management under sail; and it may as well be admitted that these are very easy principles indeed to young officers highly trained in mathematical and mechanical principles and applications. If these officers are weak in practice, it is chiefly from lack of practice. At present they are under the disadvantage of serving on board full-rigged ships, where practice under sail is so scant that they have little opportunity to become more than theorists. On board the new ships, older officers must look to their laurels, for the accurate and fresh knowledge of the young officers will then have fuller play in various directions.
What has been said thus far relates chiefly to the knowledge of management under sail and the acquirement of that knowledge through fundamentals. The extent to which we may properly carry the application into our practice on shipboard is a matter of much narrower limits. It may be stated, generally, that the limits of practice should be the necessities of current service, aiming at efficiency in a fighting sense, leaving to theory the possibilities of remote service. We must make up our minds, without wringing our hands, that a few years hence our officers will have ceased to be practical sailors as measured by past standards, but then the urgency will have abated. They will be none the less seamen, however. Up to the sailing capabilities of the new ships, officers must be eminently practical; beyond that, a well-grounded theoretical knowledge of sail must suffice. As time advances and development progresses, even theory will suffer contraction, until, finally, all but the most general principles will be abandoned to the investigator.
It will be especially necessary, in accommodating ourselves to the new Navy, to constantly bear in mind the object of its existence—to understand that whatever practice promotes fighting efficiency is good, and that whatever defeats it, whether directly or indirectly, is bad. Since sails and spars now contribute to that end only indirectly, an attempt to measure discipline or strength of organization, or to compare the efficiency of one ship with that of another, by displays aloft, will be futile. Handling sails is still necessary, but should be prosecuted with a view to utility alone, not display. Sail drill with a watch, therefore, might be deemed more important than with all hands. Spar drills should come in as a part of clearing ship for action, and should include provision for launching them overboard, and buoying and anchoring them, or rigging them as defensive booms. Spars should or should not be struck, according to circumstances. Handling spars having been established in its proper relation, i.e. to clearing ship for action, the practice gained has its secondary applications in sending down spars for chase or passage against head winds, or for repair. This is not to lose seamanship; it is simply a turn that seamanship should take. The military character of a man-of-war has very much enhanced in relation to its purely nautical character, and seamanship must bend in that direction to contribute squarely to the end in view. To say that seamanship has had its day, or that in pursuing a certain line of advisable departure we are abandoning seamanship, is to play on a word, or to declare that in future vessels will be automatic. It may be said, to digress somewhat, that extremists, diametrically separated, seem to come together in perverting the present meaning of the terms practice, practical officer, practical experience, and the like. The very conservative officer believes we are not practical unless we adhere to much of the old-fashioned practice, while the Staunch theorist decries the importance of practice, because he also associates the idea with old-fashioned practice. We may meet both of these views, by claiming, that an officer is of value to the service, just in proportion as he can apply intelligently and readily the principles which he is expected to know; but it should be borne in mind that this relates to live principles in many directions, old or new as the case may be, not alone to serving guns, quarter-deck seamanship, or boat duty.
The argument most commonly advanced in favor of continuing, what many officers regard as a superabundance of exercise aloft, is, that it imparts a cat-like or seamanlike activity to the men. If catlike activity is necessary in moderate drill aloft, military drills, pulling in boats, making signals, managing torpedoes and ammunition, caring for the ship, etc., and cannot be obtained directly from these duties, then it may be obtained from such extra drills aloft as the rig of the ship affords; otherwise, fancy drills aloft constitute a misdirected and time-consuming effort. Cat-like activity is overestimated; it has had much to do with slovenly results at quarters and in military exercises, by perpetuating the scurry which is out of place in the present day and is deplored by thoughtful officers. If we wish to impart a reasonable degree of suppleness and fail through the medium of efficiency drills, it might be well to substitute for fancy drills aloft some system of gymnastic exercises, culminating in tournament exhibitions, as less burdensome to the men. The apparatus might be light, portable, and inexpensive. Many of the Naval Academy graduates are competent to instruct in general gymnastics, boxing, fencing, swimming, and wrestling. Gymnastics, if adopted, should be obligatory.
To avoid extending this paper unnecessarily, I will confine my remarks by taking up topics very much as they occur in our standard work on seamanship. Nearly all line officers have that work, and therefore a ready reference is provided them for comparison. My object is not to criticize that work, but to use it as a convenience, because it represents the needs of the service up to 1883. After having availed myself of the table of contents of that work, so far as they suggest remark, I will pass to topics not treated therein, but which now deeply concern the seaman. It will not be possible for me to cover the whole field of official interest, however.
Chapter I.— The Ship and Definitions is of but little value in 1889. It is little more than a list of names of parts of the ship of the old type. What is to be said of the ship itself in this paper will come later.
Chapter II.— The Compass.—The Lead.— The Log.—An officer who has made the theory of navigation his specialty, lately said that from the turn naval affairs were taking, about all of navigation was becoming seamanship. Doubtless he did not intend to be taken strictly at his word, but there is no inconsiderable basis for his remark as applied to the practice of the United States Naval Service, for with us every line officer is indifferently a seaman or a navigator. The compass has always been balanced between navigation and seamanship, and with the lead and log may fairly be claimed by one or the other. In the same way, at least in our own service, where we are our own pilots, pilotage has become as much a matter of duty for the seaman as the navigator. The commanding officer is the pilot, and, beyond the question of convenience, he cares but little whether he has the assistance of the officer of the deck or the navigator. The latter has his position simply because he comes next after the executive in seniority. I lately proposed that lectures on piloting be given in the Department of Seamanship of the Naval Academy; this was at once agreed to by the Superintendent of the Academy and the head of the Department of Navigation. An attempt will be made later to show the great importance that shipbuilding and naval architecture have assumed for the seaman. The importance suggests such a considerable treatment of those subjects for his benefit that a separate work devoted to them becomes necessary. As no place can be found in that work for what remains of our former seamanship, the latter, as modified by development, might properly be embraced in a work with pilotage as one feature. Pilotage would find at least as appropriate a lodgment there, as in a book devoted to navigation. At all events, it will require at least two works to include complete instruction in seamanship. Chapter II is good so far as it goes, but, with high speeds, more attention must be given to speed indicators and to navigational sounding machines for use with wire, or some equivalent device for sounding without stopping the vessel. It is hoped that out of the swim of modern nautical change will emerge the practice of reading the compass exclusively by degrees. At a speed of 16 miles per hour a vessel steams 3S4 miles per day. The departure for 1° and 384 miles is 6.7 miles—a sufficient argument for setting the course of fast vessels to the nearest degree.
Chapters III to VI inclusive.—Rope.—Knotting and Splicing.—Blocks.— Tackles.—So far as I feel safe in predicting development, these subjects will retain much of their present interest. Details will change as experience may dictate—in some types more than others—but no radical change throughout the whole service in the direction of immediate tearing down suggests itself. Purchasing weights has left its groove with the advent of new rigs and the consequent departure of settled conditions, so theory comes to the front for stronger recognition. Rope and blocks are gradually making way for metal gearing wherever rigidity of movement is admissible, as in hoisting apparatus, boat davits, derricks, etc. It is believed that this tendency will serve to remind line officers, more strongly than any expressed opinion, that as a class they must give more study to the science of mechanism. Since the duty of engineers lies almost wholly with machinery, and their title implies that fact, it is not questioned that they should study that science, but it seems to be not generally recognized that the line officer's duties now include a wider range of mechanism than the engineer's. For example I may mention the instruments of precision relating to astronomy, navigation, meteorology, electricity, and ordnance; the mechanism of small arms, great guns, torpedoes, rapid-firing guns, machine guns, dynamite guns, steering apparatus, and deep-sea exploring apparatus; the machinery for the manufacture of great guns and their mounts, for the manufacture of rigging and other articles of equipment, and, finally, the steam engine, in degree second only to that of the engineer himself. Yet this enumeration does not fully state the case. It is too much the habit of line officers, as a class, to depend on their fine general education and varied experience for a knowledge of mechanism. The field is becoming too broad for that, and again we come to the study of fundamental principles. We must start out from the elements of mechanism in order to include, understandingly, all the applications. Herein lies one of the urgent necessities of the hour. For some years past our naval cadets have studied the elements of mechanism, and have learnt to make and read mechanical drawings and work from them. The cadets take a practical course in the pattern shop, foundry, boiler shop, machine shop, engine-room, boiler-room, and steam launches. They are also associated with mechanism in the Departments of Seamanship, Ordnance and Gunnery, Philosophy and Chemistry, and Applied Mathematics. When we reflect that a little practice counts for much with highly trained minds, and that the cadets have a great deal of practice, we must come to the conclusion that if older graduates would not suffer in comparison, they must make headway on the line which has been pointed out.
Chapter VII.—Masting.— The Rudder.—This chapter relates chiefly to wooden spars, except that an iron lower mast is described. A considerable part of the chapter retains its value, but, as a whole, it is not up to date, as might be supposed from the date of imprint. Heavier masts and yards will be made of steel hereafter, but the smaller ones may be made of wood. Inside calibers are limited to the size of a boy, who must crawl inside to help with the riveting. Tops, lower crosstrees and trestletrees, caps and cheek-pieces for heavy masts will be made of steel. In fact, steel will be used wherever it can be worked to save weight. Weight is now more often a question than room. The wooden relics are all that lend much interest to head booms. Spars and derricks should be described as elementary appliances for general use; any application to a special case will then become a simpler matter of explanation. Seamanship books have always been written in a more or less fragmentary manner, as a detail of the experience of many officers, hence the diffuseness in their treatment of the subject. Chapter VII has but little to say about the rudder, but that appliance now comes in for a great deal of attention. Quick turning is recognized as so important a quality of men-of-war, that rudder areas have been greatly increased with the invention of suitable steam, hydraulic or equivalent devices for operating them quickly. Quick full-helm action is a large factor in reducing the tactical diameter. Rocker keels, formed by cutting away the forward and after deadwoods, contribute to quick turning, while, of late, the shape and placing of the rudder has undergone improvement for twin-screw vessels, and all but the smallest men-of-war will have twin screws; in fact, we may come to triple screws before long. The lines of the new form of rudder, when the helm is amidships, are a continuation of the lines of the after body of the vessel. The rudder is hung somewhat like the equipoise rudder, and is placed so far forward that the forward edge projects into the spandrel between the propeller and the hull when the helm is over. This insures much better helm action in backing.
Chapters VIII to X inclusive.—Standing Rigging.—Rigging Ship. —Sails.—Naturally, these chapters are rather redundant for the needs of the new vessels; they refer more to the relics, but contain the essence of present needs. The fitting of standing rigging will be much simpler than it has been. Dead-eyes and laniards must give way to rigging-screws fitted with pelican hooks for immediate tripping. Top space is too valuable for working machine guns to be occupied by the eyes of the rigging, so lower shrouds and stays will set up to lugs below the top. For the same reason we may expect to find instances of pole-lowermasts in battle-ships, and of topmasts and lowermasts in one piece, or of topmasts telescoping within the lowermasts. Owing to the ample beam of the new ships conjoined with short masts, channels are obsolete and all rigging will set up inboard. Tucked eye-splices are still our resort with wire rigging, the latest having considerable drift away from the thimble to accommodate a flat seizing. The rope is tucked twice, then halved and tucked once, then quartered and tucked once. This, though strong, is difficult to make, and it is hoped that some compact clamp may be adopted. Open thimbles sometimes collapse, one leg projecting beyond its fellow and cutting the rope. It will prove a great convenience if standing jeer-blocks continue to form part of lower slings. The chief departure from old equipment will be in the structure of yards, masts, tops, derricks, boat fittings, hoisting and weighing apparatus, etc. There is yet no important change in respect to sail other than bringing the head sails inboard, reduction of sail area, and abandonment of studding sails.
Chapter XI.—Purchasing Weights.—This subject has already been touched. In any new work on seamanship, the yard, stay, triatic stay, pendants, slings, etc., should first be discussed as elementary appliances. That is done to some extent in this chapter, but not so completely as would probably have been the case had the authors written in this our day of many types. It should be understood, however, that simple treatment of a subject for shipboard use is often defeated by the necessity for giving the customary stages and orders by which operations are conducted in an orderly manner and by concerted action. Apart from the matter of simplicity. Of treatment, an officer fully informed on this chapter would not be at a loss in purchasing weights with tackles on board any of the new vessels.
Chapter XII.—Stowage and Supply.—The requirements of the new ships have left this chapter nearly obsolete, stowage having assumed much greater importance in relation to buoyancy and stability. Attention was formerly given to stowage as connected with stability—sometimes with misapplication—but not in all the aspects in which it is now considered. Stowage now has reference to buoyancy in the damaged condition; to stability both in the intact and the damaged condition, and to the behavior of the vessel among waves. Heavy articles are stowed away from the ends of the vessel in the middle body, to decrease the moment of inertia of the ship about a transverse axis and shorten the pitching period, in order that the vessel may tend to follow the motion of the heavier waves, and thus be drier. Heavy ammunition is about equally divided between the forward and the after body, or still further concentrated by being placed wholly in a central position, near the boilers. The latter may have to be discontinued because of the effect on the powder. The ammunition is stowed near the midship line, for safety from shot and torpedoes. Generally, however, heavy articles are stowed in the wings, to increase the moment of inertia of the ship about a longitudinal axis, and thus increase the rolling period, it having been found that ships with long periods are the steadiest in a seaway—at least under conditions most likely to occur. More will be said of this later. Coal is stowed in the wings, both above and below the protective deck. The latter should generally be used first, carrying that above the deck as a protection to both buoyancy and stability in the event of damage, to prevent the entrance of shot into the vitals of the ship, and to absorb the energy of the explosion of shells occurring within the bunkers. With coal above the protective deck, the volume of water, that can enter the ship in a damaged compartment thus situated, is restricted to the difference between the volume of the compartment and the volume of the coal. In this sense the coal acts as a safeguard to buoyancy and stability. If the coal above the deck stow low with respect to the center of gravity of the ship, the expenditure of coal from below the protective deck, while having the effect of raising the center of gravity and thus decreasing the metacentric height, may also increase the moment of inertia and add to steadiness. Light and bulky articles, especially articles impervious to water, will be stowed above the protective deck, to exclude water in the same way as coal, and the tendency will be to assemble stores of a single kind in one compartment. In these matters the question of convenience and of accessibility in case of emergency will have weight, of course. Stowage has now assumed too important an aspect to be treated as a study disconnected from the technical qualities of the vessel. The considerations which enter into the question must be understood.
Chapter XIII.—Boats.—Pulling and sailing boats will continue in use, and the principles of their management will not change. Details of their structure may change, or, at least, it is hoped they will, for many of our pulling boats are not well adapted to their purpose. The handle of the oar must be swung so close to the knee that the oarsman can get no swing, and appears to sit bolt upright, as if taking no interest in his work. Steam launches will be faster and lighter, and more used than ever. It will perhaps be the rule to have one of the whale-boats provided with steam power. Whether the ship's steam launches or special second-class torpedo-boats will be the dependence for independent torpedo attack is an open question. As a rule, all boats will stow inboard, to escape the blast of gun discharges. The heavier boats, especially on board battle ships and other large ships, will stow oh skid-beams. Davits will doubtless be continued in use to a considerable extent, especially for light boats and for the boats of small vessels, but derricks will be used for heavy boats, and possibly for nearly all boats in the course of time. It is not unlikely that submarine torpedo-boats will be a feature of future equipment. At any rate, submarine boats will be used in the service at large. The problem of their successful operation is nearly solved, and the study of the conditions of their operation now presents itself seriously to the service, since the Navy Department has invited designs and bids for a boat of this character.
Perhaps a few words in digression may be said about mechanical devices for lowering boats in a seaway. Nearly every graduate of the Naval Academy of inventive tendencies, including myself, has invented one or more of these devices, or has tried to invent one or more. Some of them are of great ingenuity and of more or less theoretical excellence. That they come and go in varying procession with outside inventions of the same class points to a deep-rooted distrust of them, if not to doubt as to the utility of any metal tripping device whatever, which must be operated from within the boat by a blue-jacket. The cause for this feeling, if it exists, may lie in the fact that these devices are used only in dangerous and rare emergencies, the character of which so abnormally excites the sympathies of blue-jackets that they can be less trusted than at any other time to operate mechanism properly. Yet the mechanism in question must be operated at a moment so precise that a slight non-observance is likely to lead to greater disaster than that which it is the desire to avert. Again, the mechanism is one of various pivots and long connections—a kind which, when exposed to weather at sea, requires daily care and testing to provide for these remote emergencies. Theoretically the devices get this attention, but practically they do not, nor do the men get enough practice with them to beget confidence, not to speak of the operator having his station changed. It is suggested, in this connection, that some one strike out in new lines—which suggestion may be deemed to bring this digression into line as progressive seamanship.
Chapters XIV and XV.—Ground Tackle.—Steam Capstans.—There is a tendency to modify the shape of anchors to increase the holding power and afford compact stowage and easy manipulation. The favorite shapes are those in which both flukes bite at the same time. In some cases the anchor-bed is recessed in the bow in such a way that the anchor is hove directly to its bed without catting or fishing. Rotating derricks are used also, especially for sheet anchors. Steam weighing apparatus, or its equivalent, is becoming universal, and is said to be generally lighter in the latest vessels abroad than we find it in our own new vessels—an important point, since it is not desirable to add to the heavy weights at the extremities of the vessel. It has been attempted abroad to use wire hawsers in lieu of chain cables, but apparently without enough success to warrant their general adoption. My own experience in a different field shows that it is strictly essential in any such use of wire rope—at least in the smaller sizes, and presumably in the larger sizes—that it be kept constantly taut to prevent kinking. When slacked, wire rope tends to take the form of the convolutions which it has had when wound upon its reel or drum, and there is danger of kinking when it is again hauled taut. Kinks cannot be straightened out, and they so much impair the strength of the rope that it becomes untrustworthy for its original purpose. I am at a loss to understand, therefore, how wire rope could be used for hawser cables, without some automatic device for taking through slack.. For sheet cables, the case would be somewhat different. These are used only on occasions when they would be continuously under tension, but they might kink in fouls caused by the swinging of the vessel.
Chapters XVI and XVII.—Mooring.—Carrying out Anchors by Boats.—These chapters contain so much information of continued application that no comparison, within the bounds of my purpose, suggests itself.
Chapters XVIII and XIX.—Organization.—Duties of Midshipmen.—Perhaps no known organization has ever been more perfectly adapted to complicated needs, as they were understood, than that of men-of-war of recent times. Long and varied experience by many men of executive ability, with vessels of practically the same type, resulted in a form of internal organization which met with general approval and adoption. But it is well to emphasize the fact that although it was afterwards adapted to full-rigged steamers, it was originally made to conform to the needs of that special type of vessel in which there was entire dependence on sail for propulsion, and in which the management of sail may be said to have won the day as often as guns. Sail has now become a weak auxiliary, only of use for cruising purposes, and the urgency for asserting the military character of our organization is great. It is probable, therefore, that the old form has reached its elastic limit in the wooden relics.
The organization which, of late years, has been prescribed by the Navy Department, on blank forms issued to each vessel, is the result of researches into the bills of crack ships, extending over many years, fortified by the personal suggestions of officers of acknowledged executive talent. That plan of organization descends from a nautical plane as a basis, to a military plane as an extension; but it has been questioned if the reverse plan would not secure greater efficiency on board some, if not all, of the new vessels. If we must still use the nautical basis, uniformity throughout the service can be obtained in the future by dividing the crew according to parts of the hull. Each ship might then have the same number of watch divisions and subdivisions. It is probable, since batteries vary as well as masts, that the greatest possible uniformity can be thus obtained. These department forms may not be issued to the new vessels, but it is hoped, in view of the emergency of change, which is in prospect for us in the new naval constructions and methods, that the fullest latitude will be allowed commanding officers in working out their own cure in respect to internal organization. If a past generation of officers was capable of perfecting an organization for one type of ship, it is probable that the highly educated officers of this generation will not be found less adaptive for other types.
At the present time but one idea seems to pervade this country with respect to the Navy, which is to build and arm ships. The idea that these vessels, afloat and armed, will prove more valuable to an enemy than to ourselves, unless well organized and fought, has not yet developed to the proportions of a public question. Everybody knows that mere assemblages of armed men on shore are powerless against a much smaller number of men properly organized, yet few seem to realize that a very similar principle applies to ships. The military character of the ship and the service, which is by far the highest character, because it is the only warrant for the existence of the service, does not seem to be appreciated in its proper relation. The ship as a fine structure and the officers as fine fellows are actually of no value to the country, in a naval aspect, excepting so far as they contribute to the fighting efficiency of the service. This remark is not intended to apply to any particular channel of effort; any effort whatever, in the right direction, is better than any other effort in the wrong direction.
Rear -Admiral Luce has lately written on the relation of public policy to naval organization, which in turn has relation to internal organization; and it is probable that many officers, conjointly with myself, have expressed their opinions, relative to internal organization and ratings of men, to the Board recently in session at the Navy Department to consider the question of ratings. Ratings as they have descended to us are as bad as can well be conceived for our future needs, and thorough efficiency is not to be had with them; but that question embraces too many details to be considered here.
Two features of the British Naval Service, bearing on thoroughness of organization and effort, might be introduced into our service with benefit. First, a service motto to prick our consciences in moments of laxity and to hold our object rigidly in view. The British service motto signifies "We are always ready." Second, continual insistence on the necessity of forming quickly the habit of command; that is, of commanding men. In the United States Naval Service, to a greater or less extent, an officer is expected to drift into this habit with the growth of experience, while in the British service he is encouraged or required to set about the formation of the habit with definite intention from the outset of his naval career. The manner of giving orders has much to do with the case, so I will check my admiration for younger officers long enough to say that, as a class, but with notable exceptions, they are somewhat lacking in the quality under discussion, and are not likely to make rapid progress until they improve their method of giving orders. Some advice on this point, delivered in the hope of fructification, may be tolerated.
In respect to intonation, orders should be given as simply and directly as possible—without affected mannerism. To make a display of the voice is puerile. Some officers, it is true, sing their evolutionary orders effectively by making it evident that their object is simply to gain greater range of audibility; but when an officer adopts that Style for style only, it impresses one with the belief that he leans towards the utterance rather than the execution of his orders.
In a general sense, orders may be divided into two classes. First, evolutionary and military orders, or orders demanding prompt, concerted action; as, Let fall! Hoist away! Shorten sail! Order arms! Orders of this class should be given in a sharp, mandatory tone, but with such occasional modulation that the men will regard themselves as addressed specifically and not by rote. Second, orders conveying a simple direction of a non-evolutionary or nonmilitary character as. Starboard the helm! Let go the anchor! Ease off the jib sheet! Sweep down the deck! Such orders should be given with sufficient spirit, in a business-like way; but never with the peculiar emphasis of a military order. The severe, mandatory tone so often used in giving simple directions to one or two perfectly acquiescent men is vexatious, and should not continue.
Several years ago a lieutenant, when asked to account for his successful and pleasant service under the command of an exceptionally strict officer, replied that it was because he had always followed up his own orders by knowing that they were obeyed. "A word to the wise is sufficient."
Chapters XX to XXXIV inclusive, except Chapter XXI.—Port Drills and Evolutions.—Getting under Way under Sail.—Making and Taking in Sail.— Working to -Windward.— Wind Baffling.—Heaving-to.—Reefing.—Law of Storms.—In a Gale.—Parting Rigging.—Losing Spars.—Shifting Sails and Spars.—Coming to Anchor.—Handling Fore and Afters.—With respect to these chapters it is not necessary to say more than has been already said in the first part of this paper; to go more into details would only serve to consume time. It will be apparent to all that the matter given in the book refers to a far greater extent to the wooden vessels than to the new ships; yet there is much information of general application. The law of storms is known to all our line officers, from the highest to the lowest. I will repeat that my object in referring to our work on seamanship is merely to have a basis for comparison.
Chapter XXI.—Rules of the Road.—Rules of the road are readymade, and no independent action respecting them is permitted unless it be the abstract one of suggestion. Various devices and systems of lights have been proposed as substitutes for those now in use, with a view to abate the danger of collision afloat. Most of these, if adopted, would only complicate the situation and thus lead to greater disaster. However simple the present system may appear to educated minds, it is nevertheless so confusing in some of its practical phases to some other nautical minds that it often fails of its object through this cause. To oblige the latter class, from which we must expect the greatest failure in the aggregate, to wrestle with more intricate combinations will add to present danger. The danger of collision is greatest when vessels suddenly heave in sight at close quarters, when there is the least time for studying combinations on which to base correct judgment. Effort should therefore be directed towards simplification. Doubtless such considerations as these have prevented the adoption of new systems.
Chapter XXXV.—Handling Vessels under Steam.—This chapter is modern, and embraces much more valuable information to the point than I have been able to find in any other work on seamanship, but the treatment will doubtless be different in future works. Some examples of steering mechanism are given, but nothing concerning hydraulic mechanism. Those parts relating to turning effects of the screw, especially of twin-screws, and the turning power of ships, point the way to lines of study daily growing more important to the man-of-war seaman than matters relating to sails. Here we must go to fundamental principles again; it is not enough to know the effects, we must know more about causes. In considering drift-angle and kick, for instance, we must know what impulses conspire to produce kick. These subjects lead up to naval tactics under steam, a branch of our profession which is yet in an unsettled state no system having met with much favor remote from the locality of its author. At the Naval Academy the general subject of handling vessels under steam will begin at the resistance of fluids, and will continue through surface disturbance, the action of propellers, simple and as effected by the features of the ship's resistance, rudder pressures, and the phenomena of turning a ship. In addition, the refinements involved in these several divisions of the subject will be taught to advanced sections. Young officers, who compass that course, when it shall have been completely established, will not be likely to regard the handling of steamers as involving mysterious movements or expect unaccountable eccentricities in moments of emergency. The possible advantage to men-of-war of high speed and turning power, especially in ramming, is admitted to be very great, and even slight advantage may be vital; therefore the investigation of principles has its value in preparing officers to discover and improve advantages, or, at least, to know where they might lose them through neglect. So many of our officers have read up this subject that the importance of studying it as indicated will hardly be questioned.
Chapter XXXVI.—Getting Ashore.—Leaking.—This chapter relates chiefly to expedients for getting afloat, repairing leaks and to seamanlike procedure, and embraces the teachings of much valuable experience. It is unnecessary to say that any information which serves the purpose of this chapter will always be acceptable to seamen. Anything that I may have to say regarding grounding and leakage will come in later.
After this chapter comes a chapter on the Life-Saving Service of the United States, of undoubted value, and then follow certain appendices relating to rope-making, marline-spike seamanship, management of boats in a surf, miscellaneous routine, clubbing, backing and filling, tending ship, fire-booms, turning experiments, speed and steering trials, etc., some of too much value to be questioned, while as to others my remarks already made are sufficient. I will now abandon our seamanship work as a reference, and discuss matters independently of it.
It must be apparent to many of those who have reflected on the bearing which naval development will have upon the duties of officers, that lines of study are now forced upon the line officer, the necessity for which has not been generally recognized heretofore in our service. The attention of the line officer as a seaman is now directed mainly to the hull and that which pertains more or less intimately thereto; and we find that the diversity of structure, fitting and equipment is great, the character of risks varied and novel, and the responsibility immense. With the new vessel, directed by intelligence and knowledge, great feats may be performed; but, on the other hand, great blunders may be made through ignorance or misconception. Even very limited reading indicates that we must have a far more accurate knowledge of our new ships, their structure, strength, qualities, behavior, management and possibilities, than we had of the wooden ships; and this is true not only as to individual ships, but as to ships relatively to one another. Theory, therefore, is more nearly indispensable to complete fitness than formerly.
Theory must begin with a study of types, in a general, historical sense as well as specially. If this must be pursued individually, the only recourse is wide and continued reading. Since this may be more or less discouraging, because of non-availability of the literature of the subject, it is to be hoped that post-graduate instruction will be afforded as a relief. In any event, the field is too wide and too much filled with detail to be covered without persistent reading and comparison. Officers must become saturated, so to speak, with a knowledge of types, in order to comprehend on all occasions the value of their own force relative to another force. From types we must go to structure, general and special. We must know how ships are constructed, arranged, and provided with safeguards and expedients, and, at least in a general way, the magnitude of the strains, local and structural, to which they may be subjected, and their capability of resisting them. We must also have a knowledge of theory and applications pertaining to the buoyancy, stability and management of ships, to their behavior among waves and under other and varied circumstances. All this, let it be understood, in a higher degree than heretofore, and strictly as demanded by recent development.
If there are any who fear the abandonment of sail and the decadence of top and marline-spike seamanship, because of some supposed influence in degrading the functions of the line officer, to them a word may be said.
I am only giving utterance to well-recognized truisms when I say that there is no higher study which may properly come under the term seamanship than that which investigates the qualities, behavior and management of vessels, and no higher practice pertaining to shipboard than management of the vessel, the control of her behavior, and, in general, the use of her qualities. It is here that we find play for intellectual effort, combined with the rare and high personal qualities that lead to great naval achievements, followed by national gratitude and reward. In respect to this phase of seamanship, we suffer in nowise by the abandonment of sail. In the new Navy, the requisites for success are somewhat different from what has been demanded in the past, but they are distinctly on a higher plane, and there is a broader field for the exhibition of practical excellence. It is no longer possible to compass the range of naval seamanship as one learns a trade. A second mate, by virtue of his seamanship alone, cannot again be transmuted into a naval officer. The naval seaman has much to gain and nothing to lose in pride of position by encouraging development: he needs only to see the situation and to prepare himself for it.
I will now proceed to justify my belief by amplifying on the preceding statements, but only so far as to show in some degree the interest of the subjects presented: it should be understood that I neither presume to teach principles nor to do more than trench on the ground to be covered. I am also aware that my paper will contain nothing new to a fair proportion of officers.
A characteristic of modern naval architecture is the nice apportionment of weight displacement among the several qualities aimed at in the design of the vessel. To get many desirable qualities in high degree in a single vessel is possible only with a displacement so great as to sacrifice handiness and light draft, not to speak of the risk of concentrating, in a single fighting unit, an excessive proportion of the national power of offense and defense. This has forced upon us a multiplicity of types, each type having in a high degree those qualities which, according to one interpretation or another, are deemed most necessary to the performance of the special service for which the type is intended; and these qualities are attained always at the expense of other qualities deemed less essential to that service. For instance, the coast-defense vessel absorbs a high percentage of displacement for armor and guns at the expense of speed and endurance of supplies. In fact, these latter are reduced so low in the scale that thick armor and heavy guns are secured, with comparatively light draft and moderate load displacement. Again, the unarmored cruiser sacrifices weight of armament and dispenses with armor, reserving thereby a certain amount of displacement, which is apportioned to high speed, coal or cruising endurance, and more or less sail power. When high speed is reached, a small increase of speed can be gained only at a comparatively great expense of weight displacement. Since the attainment of qualities is not broadly optional, the seaman, however skillful he may be in the use of qualities, is hardly in a position to compare types and criticize special designs intelligently, or to insist on special qualities, unless he has some knowledge of the restrictions which bind the naval architect. The day when one class of vessels was simply a modification of another class of the same type, in structure and qualities, and when the qualities of one ship were commonly prejudged from those of other ships already built and tried, has given way to a period of costly and novel constructions, whose qualities must be foretold, in large part, by calculation.
In the various types of the later war vessels there are certain general structural features common to all, viz. metal construction, watertight subdivision, water-tight or protective decks, draining and ventilating systems, and a variety of mechanical devices to replace rope. In structural details, however, there is great diversity, to support armor, provide for the installation of guns, torpedoes, engines and boilers; to arrange for ammunition supply, stowing, berthing, draining, pumping, lighting, etc., and to guard against the loss of buoyancy and stability through damage at and below the water-line. When we connect all this detail with that of the general structure and of minute water-tight subdivision in every direction, and remember that some ships have as high as 200 compartments, can there be any doubt as to the desirability of line officers having a fundamental knowledge of naval construction, embracing the qualities and working of the metal, the different systems of framing, plating, armoring, strapping, butting, riveting, caulking, and so on, through a long list that has been anticipated in previous remarks? Not only must he know the form and position of details, but also the considerations which move the designer to use one detail or system instead of another. What we want is that an officer shall be able, from a study of drawings and one or two tours of inspection of the ship, to stand in any part of her and picture to himself the exact appearance, condition and arrangement of every other part of her; and the only hope of reaching this state of things is through fundamental knowledge. Intercepting bulkheads, flats and decks make it difficult to conceive, simply by tours of the hull, the relation which one subdivision of the ship bears to another, but drawings will make it clear at a glance. The intricacies of modern war vessels have become so great that in the British service, at least, two executive officers, one a commander, are detailed for vessels of less displacement than some we are now building. This is done, mainly, to provide suitably for the care and preservation of the various subdivisions of the vessel. The commander has general charge of executive duty under the captain, and the first lieutenant has charge below the upper deck under the commander.
Not only must officers themselves have a knowledge of structure, but they must instruct the men in the same knowledge. With the waning of top seamanship, we will lose the display of reckless courage aloft, but we will have greater intelligence and a wider range of information regarding the hull and its details.
At a less percentage of the total displacement, steel hulls have greater structural strength—i.e. strength as a whole—than wooden hulls, but, at the same time, they are locally weaker, and subject to rapid deterioration through causes that but little affect the latter. They demand, therefore, greater care, closer inspection and a more extended knowledge of the conditions and methods of preservation. With care, however, they may be continued in service, incomparably longer than wooden hulls, without extensive repair. Sweating is a characteristic of metal ships that must be guarded against. It is said of the large Italian men-of-war that it is necessary to change their detail of officers frequently, as a health measure, on account of excessive dampness. In regard to corrosion, the outside wetted surface and the intercostal hold-spaces give the most trouble. Cement is used in the bilges and waterways; but while cement, properly applied, is a perfect preservative, it is a source of danger if it loosens and allows the entrance of water between it and the metal. The speed of metal vessels is not only decreased for the time being by fouling of the bottom, but permanently also by the resulting roughness of the plating.
Buoyancy as an independent study is not new to graduates of the Naval Academy, but the recent writings on the buoyancy of ships, embracing the thought and experience of the new period of naval construction, will suggest ideas not likely to occur in general service afloat. In the structure of the wooden ship there was no protection to buoyancy other than that due to the great thickness of frame and double skin: water-tight subdivision was not attainable. In the steel ship, with her thin and more easily penetrable skin, there is greater need for such protection, and, fortunately, it has been effected to a considerable extent, by virtue of the qualities of the metal and the greater structural strength which it affords. But this new phase of construction opens up questions relating to buoyancy not considered in the days of wooden ships. This protection is not complete; it is one of degree only. In certain types of ships it is not even attempted to prevent the entrance of shot into the hull, but simply, by means of water-tight subdivision, occupation of space by water-excluding stores and employment of contractile substance, to so localize and minimize the inroad of water on buoyancy that the probability shall be against the annihilation of the reserve buoyancy by accident or the damage of battle. But damage may be much or little, and the percentage of reserve buoyancy to total floating power varies greatly in vessels, ranging from that of the submarine vessel as a minimum to that of the high-freeboard cruiser as a maximum. Although buoyancy may not be wholly destroyed, yet so small a margin may remain that sinkage can be prevented only by a nice comprehension of the situation to be met. Again, buoyancy may be ample, but by encroachment upon it, stability may be lost unless carefully guarded; speed may be effected, trim altered or draft increased. To know what action to take when buoyancy is at stake, the line officer should be able to comprehend his risks. He should be able to estimate the change of draft, the inroad on reserve buoyancy, and the change of trim which would result from flooding one or more compartments of his vessel; the amount of water that would enter the vessel through any area of damage at any depth in a given time, and the capacity of the pumping system to preserve or restore reserve buoyancy in assumed cases of damage. It may be said generally, however, that no ship has sufficient pumping capacity to constitute in itself a complete protection to buoyancy excepting against ordinary leakage or slight damage. Through a hole sixteen feet below the surface of the water and one square foot in area, sixty tons of water per minute or 3600 tons per hour will enter the ship initially. The chief dependence on the pumping system, in the event of great damage, is in clearing the ship of water after leak-stoppers have been applied. This relation of the pumping system to buoyancy is recognized in the construction of the British ram Polyphemus, a vessel of small reserve buoyancy. She is provided with several hundred tons of detachable ballast, which may be let go at a critical moment. The following are means for the protection of buoyancy, viz. armor, water-tight decks and bulkheads, double bottoms, coffer-dams, water excluding stores, cork, ordinary coal, patent fuel in rectangular shapes for compact stowage, a contractile substance called cellulose fitted under pressure into water-tight compartments, pumping and draining systems, leak-stoppers of various kinds, hauling down chains, sheet lead to make templates of leaks and the locality of leaks, cement to fother leaks within the vessel, diving apparatus, etc. It is true that this list embraces details readily used by ordinary intelligence, but it is in respect to a comprehension of the character and extent of damage as bearing on the safety of the vessel that the subject of buoyancy invites greater attention than is now given it.
It is probable that the loss of the U. S. monitor Weehawken was due to unenlightenment as to the conditions of flotation of that vessel. She was sunk at her anchors off Charleston during the late war, by water flowing over her decks and down the forward hatchway into the anchor hold. It was blowing a gale at the time, and the forward hatch was open; but the situation, except, perhaps, as to an extra supply of ammunition and coal on board at the time, was not exceptional for that vessel. The nature of the accident, and the unexpected result following so quickly the first signs of danger, lead to the belief that the vessel had far less reserve buoyancy than was imagined by those on board. It can hardly be supposed that a like accident could occur at this day.
As a result of the employment of a variety of types of ships with different heights of freeboard and conditions of service, and subject to different degrees of damage, there has arisen the necessity for a better knowledge of stability. The conditions of stability, affecting the handling of ships in a damaged state, are far more critical than those of buoyancy. A vessel damaged above the protective deck may retain ample buoyancy for flotation in the upright position, and yet have become so crank, through loss of water-line area and the consequent reduction of metacentric height, that an attempt to turn her in a small circle would cause her to capsize. But a vessel in such a condition might be handled in a way to continue serviceable to a fair degree. In future naval battles we may expect that many more vessels will be capsized than sunk. This phase of fighting accident did not exist in the days of wooden ships; it has come with the new types, and the knowledge to prepare for it should form part of the line officer's intellectual equipment.
In the light of the present knowledge of the subject, it is plain that vessels have been lost through ignorance of the conditions of stability rather than careless disregard of them. Investigation of the question received a great impetus by the sinking of the British turreted low freeboard man-of-war Captain, a vessel provided with large sail power. She had exceptionally good stability up to the angle where her upper deck dipped, when it soon began to fall off so rapidly as to render her unfit for her canvas under circumstances of weather and sea to which cruising made her liable. She was capsized in the Bay of Biscay while under sail, carrying down with her nearly all hands, including her designer, a naval officer. Her loss is monumental as an instance of the temerity of attempting great technical feats without a knowledge of the fundamental principles involved. The loss of the Captain may be said to have settled the question of freeboard as related to stability, but the question of stability in the damaged condition, with respect to types, is viewed so differently among naval architects that, if for no other reason, the naval officer should look carefully into the subject himself. The question hangs chiefly on the probabilities in warfare, and is therefore very much a matter of speculation at present; nor is it likely to be settled, except by disasters of which naval officers must bear the brunt of danger and responsibility. The stability of a vessel changes with the weight which she carries, and with the position of the weight. For ordinary service this concerns the merchant vessel more than the man-of-war, but when warfare is taken into account, the reverse is the case. It is not my intention to touch oh principles further than to give at least a slight indication of the importance of the study, but within this limit attention may be called to the several ways in which stability may be affected by water entering a vessel.
1. A compartment may be filled with water which it completely encloses, in which case stability will be affected in about the same manner that it would if the water were replaced by a solid body of equal weight and having its center of gravity in the same place.
2. A compartment may be partially filled by water which it completely encloses. In this case the water is free to alter its form and position with the vessel's rolling motion, and the effect on stability is similar to that of a weight moving about unrestricted within certain limits.
3. A compartment may have water in it in free communication with the sea and at the sea level for all inclinations. In this case the effect is the same as if the vessel were deprived of so much of her volume as is thus occupied by the water. Her weight remaining the same, the vessel must have increased immersion until the additional volume of displacement equals the volume of water in the damaged compartment. Stability is affected; the center of buoyancy and metacenter having a new position.
The primary use of a knowledge of stability to the seaman is not necessarily to make calculations, but rather to distinguish between cases and to interpret aright the technical qualities of the vessel from the graphical and numerical data which will be at his command. The information of greatest value may be stated as follows: Under various conditions of load, the metacentric height or the initial stability; the angle at which the deck is awash; the angle at which the maximum stability is reached and beyond which the righting force diminishes; the angle at which stability vanishes; the effect on stability of adding, removing or shifting weights, and the effect of under-water damage. Officers will be expected from time to time to perform the inclining experiment with the completed ship, to determine the vertical position of the center of gravity.
Officers having a desire to gain a fair knowledge of stability need feel no discouragement on the score of mathematics. Mr. W.H. White, in his Manual of Naval Architecture, manages to impart a fair knowledge of stability without going into mathematics beyond a right-angle triangle, but a further resort to mathematics is necessary in treating the refinements of stability.
Sir Edward J. Reed, in his work. The Stability of Ships, says: "In this work the author has endeavored to make the earlier chapters intelligible even to those who do not understand mathematics, and in those earlier chapters will be found all that many persons who are concerned with ships require to know. But nonmathematical readers should not be deterred from pressing on with their study of the subject by the occasional intrusion of a sign of integration or other mathematical symbol. The general sense and purpose may often be easily mastered even by those who cannot interpret the mathematical expressions."
A fair knowledge of stability is also essential to an understanding of the conditions of the behavior of ships among waves, which has relation to value as a gun platform, as well as to structural strains and personal comfort. The naval seaman should know under what conditions of sea and stowage his ship will fight to the best advantage, and ride out a gale or make a passage most comfortably and safely. All this may be so nearly predicted in many cases before leaving port that at least the amount of experience necessary to form conclusions is very much narrowed down by the study of theory.
It is only of recent years that the investigation of wave-motion and of the behavior of ships among waves has reached the stage of broad, practical application. Fortunately, the leading principles involved, and their practical bearing on management at sea, have been admirably and simply treated for the benefit of seamen.
The conditions governing the behavior of a ship among waves appear to be:
- Her period of still-water oscillation—i. e. the time occupied by her in making a complete swing when set rolling in still water.
- The magnitude of the fluid resistance to her motion, a measure of which is afforded by the rapidity with which she is brought to rest after being set rolling in still water.
- The dimensions and proportions of the ocean waves encountered; also their speed and direction of approach to the ship.
Over the first and second of these conditions the designer of a ship may exercise considerable influence, but not in all cases. This may be explained in a general way as follows:
Synchronism of the still-water rolling period, or natural period, of a ship with the half-wave period produces extreme rolling. It is therefore an object of the designer to give the ship a period which will not synchronize with waves large enough to greatly disturb her, and it has been found by observation and experience that this is best fulfilled by a long period. High metacentric height—i. e. great stability—which governs the quality of stiffness, gives a short period and is opposed to steadiness, so increase of period is sought through moderate metacentric height and increase of the moment of inertia, the latter being governed by the disposition of weight with respect to the center of gravity of the ship. Other considerations than rolling also influence the disposition of weights, so the designer is not always at much liberty in the pursuit of steadiness through increase of the moment of inertia; hence some designs show decided pre-eminence over others in this respect. For instance, the British ship Inflexible, with echeloned turrets, great weight of side armor and other winged weights, has about twice the metacentric height and about the same rolling period as the Italian ship Duilio, with turrets on the middle line and generally greater concentration of weights amidships.
Although the influence of the designer on the period of a ship may be limited, he has considerable scope in augmenting the fluid resistance, which he exercises chiefly by the use of bilge keels, the effect of which is to quickly extinguish rolling after it has begun. Over this power the seaman has no influence, but he oftentimes has over the moment of inertia—though to a less extent than the designer—by regulating stowage and the expenditure of dead weight. His control is greater, however, over another means of extinguishing roll, that will doubtless be adopted into some of our new vessels. When water within a ship is free to move from side to side, it exercises a more or less powerful effect on the roll, and advantage has been taken of this property to fit athwart ship water-chambers above the armored deck of certain ironclads having considerable metacentric heights and comparatively short periods. Into these chambers free water may be introduced at discretion. The seaman may also oftentimes influence the relation between the ship's period and the wave period to bring about a relation favorable to steadiness—an exceedingly important point, in view of the absence of sail in some men-of-war. This may be done by diminishing or increasing speed, or changing the course relatively to the advance of the wave, whereby the apparent wave period is lengthened or shortened and synchronism avoided. This involves, of course, some knowledge of wave motion and of observing wave periods, but no more than may be readily acquired.
Although what has been said is very general, it has shown that the behavior of ships is more or less under control when in charge of officers competent to take heed of the governing conditions, and that we are by no means "left in the lurch" by a deprivation of sail.
Both as an educational measure and as an insurance against loss of government property not quickly replaced at any cost, it is to be hoped that every United States man-of-war commissioned hereafter will be amply provided with the graphical and numerical data, which scientific investigation and method of presentment has made available for the naval officer during recent years. This data is copious, and comprehends the qualities of the ship in every direction. Much of it is of greater value in the graphical form. Heretofore we have not done much in this respect. The commanding officer has been provided with a sail and rigging plan and the deck plans of his ship, with a few figures relating to the battery and engine, and but little if any more. They have had nothing concerning the ship's history or qualities, although dozens of semi-annual reports may have been sent in from her from time to time during her several cruises; yet they have had the history of each man who has had a history. I received command of one ship said to have a considerable amount of ballast on board, but there was no official word about it. She was a sailing ship, and therefore dependent on water supply from on shore. Her tank capacity, as laid down on the hold plan, was far in excess of the truth. With the exception of the last item, I am speaking of long-established custom—or, perhaps I may say, lack of custom. This should be and doubtless will be changed now, and it is to be hoped that ships will be provided most amply with drawings, both general and special, relating to every quality and feature concerning which information would be either useful or interesting. At least one British shipbuilding firm issues, for vessels built by it, a book called the "Technical Qualities Book," which embraces graphical and other data relating to the vessel. This is what we want for our ships—a volume containing the history of the ship, and a detail of her qualities and features in every department. Commanding officers might be supplied with a book comprehending everything available, and other books embracing only non-confidential information might be provided in sufficient number for issue to other officers on board.
The following are some of the graphical curves which are of interest to the seaman as embracing data bearing on the vessel's qualities. The list might be greatly extended.
Curves Relating to the Strength of Ships.
Curve of buoyancy and curve of weight.—These curves are commonly associated in a single diagram. They represent the distribution of weight and buoyancy and the excess of one over the other at each part of the vessel's length.
Curve of loads, indicating the unequal distribution of weight and buoyancy at each part of the vessel's length.
Curve of shearing forces, giving the shearing or racking forces along the length of the vessel considered as a beam and at rest in still water.
Curve of bending moments, giving the bending moments along the length of the vessel considered as a beam and at rest in still water.
Curves of shearing forces and bending moments among waves, giving the maximum shearing force and bending moment which the vessel will have to resist according to calculations based upon two assumed conditions, in which the maximum stresses possible are exerted, viz. when the ship is on the crest of a wave of her own length, and when she is in the hollow of a wave of her own length. The height of the wave is taken at one-fifteenth of its length.
Curves Relating to the Flotation of Ships
Curves of displacement, giving the displacement of the ship for any mean draft of water.
Curve of tons per inch of immersion, commonly called the curve of tons per inch, giving the weight necessary to increase or decrease the draft of the ship one inch when floating at a known draft.
Curve of moment to change trim one inch, giving the longitudinal distance through which it is necessary to move any known weight horizontally to alter trim by one inch, or the weight which it is necessary to move horizontally through any given longitudinal distance to alter trim by one inch.
Curves Relating to the Stability of Ships.
Metacentric diagram.—This commonly contains the metacentric curve or curve of metacenters and the curve of centers of buoyancy, showing- the positions of the metacenter and center of buoyancy relative to the water-lines and to each other at any assumed mean drafts. Without the positions of the center of gravity being known, the metacentric curve merely shows the tendency to stability due to the vessel's form; but by indicating upon the diagram, as is often done, successive positions of the center of gravity also, the statical stability of the vessel at any draft may also be determined with tolerable accuracy from the diagram.
Curve of statical stability, or simply curve of stability, gives for stated conditions of lading and damage the righting forces of the vessel at successive angles of heel, the angle of maximum righting force, and the angle at which stability vanishes.
Curves Relating to the Speed and Turning of Ships.
Curve of speed and power, representing the indicated horse-power and revolutions corresponding to any speed of the ship. The data for this curve are obtained by progressive speed trials of the ship.
Tactical diagram or turning circle, representing the path of the ship at a given speed and helm angle. From the diagram we also get the tactical and final diameters of the ship's path, her advance and transfer from the origin of the path to any other point on the path, the time occupied in passing from one point to another, the drift-angle at certain points, and the effect on the path due to kick.
The applicability of several of these curves to ordinary or extraordinary service will tend to show the increased power that seamen are gaining over ships.
Curve of displacement.—Dry-dock companies sometimes base their charges on displacement. The curve provides a check on the company's figures.
A ship leaves port at a known mean draft, and grounds so hard as to require a discharge of weights. If the mean draft while aground can be obtained, the corresponding displacement may be found from the curve. The difference between this displacement and that corresponding to the first mean draft is the weight to be discharged in order that the ship may float.
Curve of tons per inch.—In the case of the ship aground, the number of inches by which the ship is aground multiplied into the tons per inch corresponding to the new mean draft, or to a mean between this mean draft and the mean draft of flotation, gives, approximately, the weight necessary to be discharged as before.
By keeping account of the weight of coal and provisions consumed at sea, the curve of tons per inch affords an approximate means of finding the mean draft with which the ship will enter port; also having the mean draft for salt water, it affords a means, with the aid of the displacement curve, of finding the increased draft when passing into fresh water, and the reverse.
Curve of moment to change trim one inch.—A vessel grounds at either extremity, causing her to alter trim. If she can be made to take this trim normally, by moving weights longitudinally, she will float. The curve gives, approximately, the needed information.
A vessel having considerable drag, or a skeg, can cross a bar by altering trim; the curve gives the required relation between movable weight and longitudinal distance. Some modern men-of-war have trimming tanks in the fore and after peaks. The amount of water to be taken into a chamber may be found, approximately, from this curve and the curve of tons per inch.
Curve of stability.—If the graphical data be sufficient, the stability of a vessel in any condition of damage may be found from the curves at a glance. The risks being known, she may continue to her destination or make for the nearest port, accept or decline assistance, and continue or avoid a fight.
If it were asked where this new or extended knowledge of seamanship is to end, I should reply, at designing. Short of that, the more of this kind of information possessed by the line officer, consistent with thoroughness in other professional branches, the better for the service. Ship-designing, however, is a profession in itself, and one sufficiently exacting of energy, knowledge, and time to engage the whole attention of any man, whatever his talent. Analogy is not wanting to support my views, for it has long been thought desirable that every line officer, in addition to gunnery, should have a knowledge of ordnance, from the preparation of the metal to the completed structure, embracing the tools employed and every detail of manufacture; yet it has been recognized that ordnance designing is a specialty.
So much has been said about theory and fundamental knowledge, in this paper, that it may be well to explain that I do not undervalue practice, but, on the contrary, would associate it with theory to the greatest possible extent. In fact, information derived from practice, when equal, is always to be preferred to that gained by the study of books; but I will reiterate, that, in my opinion, ordinary service, as a school, no longer affords full opportunity for acquiring the range of knowledge needed to prepare for emergencies. Again, I do not attach equal importance to all branches of the proposed line of study, but regard that which relates to handling vessels, in general, as the most important.
My paper is already much longer than I had wished to make it, so I will not consume time by attempting to carry seamanship into tactics, or to define the exact limits of seamanship relative to kindred matters. That would hardly suggest any study, the necessity for which is not now recognized. If it is accepted that I have not left the domain of seamanship thus far, it has, perhaps, been made apparent that the reduction of sail area has no tendency to degrade the functions of the line officer. The idea of the general public is, that the line officer is only a seaman; very little is known of his character as an infantryman, light artillerist, heavy artillerist, naval and military tactician, navigator, hydrographer, expert in high explosives and the appliances of war, repository of the service knowledge of what is called the art of war, and of international law; disciplinarian, magistrate, judge, jury, and administrator afloat, and as the agent of his Government in affairs oftentimes of the greatest national concern. Leaving all this out of consideration, however, there is enough in future seamanship alone to satisfy official pride and to give the line officer ample reason to insist on rapid development in the new direction.
A noteworthy condition of the attainment of the new or extended seamanship, as laid down in this paper, is that it must come mainly from the published works of naval architects. It will not be found in works devoted to seamanship alone. In good time, after we shall have had experience with the new ships, it will doubtless come about, that we will reverse the case and give naval architects suggestive points in their own profession, but the burden of obligation is upon us at present. The benefit likely to result to us in the exercise of our duties by a ready recognition and admission of this state of things ought to be generally apparent.
Last year an officer of ability said to me, in good part, that the seamanship department of the Naval Academy had not progressed since 1868. This did not hit me hard, because I was a newcomer; but such an opinion, if actually held, would be unjust to my predecessors. The course of study has gradually improved since that date, and much of the new matter, to which attention has been called in this paper, has been taught for several years past; but the need for suitable textbooks has been very discouraging. At present, Naval Constructor Richard Gatewood, U.S.N., is giving a series of lectures on shipbuilding and naval architecture to the cadets. These lectures are printed and issued to cadets and instructors. They are specially adapted to our needs, and it is hoped that they will result in a publication available for the service at large. In other respects the department is being brought up to date as rapidly as our facilities will allow, but time is an element of progress in this as in other matters. The chief source of concern is the outside service, not the Naval Academy.
In concluding this paper, I think Naval Academy graduates may permit themselves to feel a hearty satisfaction at the complete vindication of our system of naval education, by recent naval development. The Academy was established in 1845, and its graduates are found in the various grades of the line through the highest commanding rank for a single vessel; yet until very recently it has had vigorous opposition, more or less on the supposition that its scientific methods were opposed to practical efficiency. The gratifying result of the Academy education is, that line officers as a class, and a large proportion of the engineers of the service, are fit to meet development in whatever direction it may affect their respective duties.