In an effort to stimulate discussion, the writer has set forth certain points in connection with naval engineering which were noted during destroyer service in the war just ended. Consideration of this subject should be most profitable while occurrences are still fresh in the minds of those who performed engineering duties. Another endeavor in this article will be to show how intimately connected engineering designers and operators are, or should be, by purely military consideration, for there seems to be a sentiment in our service that engineering is less influenced by wartime operations external to it than any other branch of the service, or, in other words, that it is a profession apart.
What our service needs is naval engineers trained in the art of war, and not marine engineers alone. War experience and War College training in addition to purely technical training are vitally important for our engineering specialists, especially the designers.
The writer believes the requirement, that engineers have a thorough knowledge of war, is so important that there should be an engineer officer of high rank and long experience at the War College to give consideration to the location of fuel supplies, quantities necessary, the effect of known oil and coal fields on choice of naval bases, and influence of enemy fuel supply on their operations and our offensives; protection of oil and coal fields, best disposition for spares, patterns, stores, etc.; to keep the Office of Inventions informed of the nature of new developments required; to make up schedules of engineering casualties for war games with reasonable penalties for same; to learn the war game from A to Z; to study the effects of this and other wars on engineering design and practice and that of probable future developments; to determine the missions for various engineering boards, bureaus, offices and officers, etc.
It can be only under the strong stimulus of such War College training that the impulse will come to project the mind into the future and to devise new methods, new designs, and to lay out the path that engineering minds should follow, in order to meet military and not engineering requirements, as such.
The magnitude of the necessity for many things cannot possibly be brought out any other way, and such training for engineers, or some of them at least, would certainly form a connecting link between those selected for engineering only and those not so detailed, which will enhance mutual confidence between these two groups and will prevent the creation of individual corps spirit.
Many subjects, new and heretofore given little, if any attention, have come to light during the war just over, and it is the search for still newer ones in the light of probable future developments which the War College course would stimulate and facilitate. For designers to direct their efforts along proper and profitable lines, some general outline must be at hand and a general object must be in view. The tremendous importance of good design, as the writer has in a previous article pointed out, is too little emphasized in our service. It is good design that wins out in the fight for economy, speed or whatever else we strive for, more than good management, although that, of course, is necessary, but at any rate in our service, this is almost universal and can be considered as routine and nearly a constant factor. But give the best manager or operator in the navy a poorly designed plant to work with, and competition with a well-designed plant, only moderately well managed, is out of the question. Assuming that design is at all events important, there is no need for further expansion on its value.
Now given the necessity for certain requirements, good design and the inventive genius so marvelously developed along mechanical lines in the American, will, inevitably, fill the bill. Inventions and new arrangements proceed from necessity invariably, as surely as demand creates supply, and it is for this reason that the writer so strongly believes that this necessity, created in advance of actual requirements by the studies and games of the War College, should be transmitted to engineering designers and kept up to date by a member of the specialized engineering personnel, who is stationed at the War College and is in intimate contact with all of its transactions. Invention has, of course, in some cases, been the outcome of some happy detached inspiration, but it more normally and frequently proceeds from logical and consequent demand for greater efficiency in some machine or contrivance already existent, in elementary or imperfectly developed form, in which the requirements of further development are, in a way, definitely known. The general trend of future development to meet our future military needs, then, is what the War College engineer member could and should supply.
As an illustration of the sort of thing that comes to mind in connection with a study of war operating conditions, and which could never proceed logically from a consideration of any portion of an engineering plant, from a purely engineering point of view, let 11s take the subject of the concealment of a large body of ships at night.
All officers who were at sea during the present war are familiar with darkening ship and the many deficiencies that were found to exist in the lighting arrangements in engine rooms, etc., when it became necessary to douse certain units, which before had been relied upon to light up gauges, thermometers, etc. And also everyone realizes how much importance was attached to this subject. However, at that time there was no overhead observer to fear.
In the light of recent aerial achievements, this will, in the future, become quite an important point. The matter of shielding electric light is quite simple, but the glow from a white hot oil burning furnace projected up a stack can be seen in some types of boilers, and, whether or not this is serious, it serves to illustrate the point.
It will at once be seen that this is purely a matter of engineering design, but that the thought of seeking protection of a fleet by concealment would never logically enter the head of a designer, looking at the matter from an engineering standpoint alone. Hence it becomes evident that some outside influence must be brought to bear if naval engineering is to be what the name implies, and not simply marine engineering, and this influence can be and is believed best supplied by the War College through some engineer undergoing war training there.
In the discussion of some of the numerous occurrences and engineering matters presented here, an attempt has been made to bring out the military importance of them, as well as the purely technical side, and while these remarks apply in general to destroyer engineering only, they will serve to stimulate discussion and to promote the idea that a naval engineer is as much a military official as those officers in other departments of the navy, and will, it is hoped, militate against a great step backward, the segregation of engineers again into a distinct corps, by unwritten if not actual law; which at the present time seems probable and which will inevitably involve all the evils of the old corps system, which required many years to overcome.
The discussion of various matters, which came to the attention of the writer during the war, will now be taken up. As there is no logical connection between them, they are not given consecutively, but as they come, and each is independent of the other.
From a consideration of the number of times destroyers were late for convoys because of the failure of some minor auxiliary or were unable to make maximum speed for the same reason, it is believed that reliability should be the primary consideration, even at a sacrifice of great subdivision in units as a protection against total disablement and in the interests of economy. Instances are innumerable where it became necessary to send destroyers to sea with one or more blowers out of commission, for example. It is evident that maximum speed, which would most probably be needed in an engagement, could not be made in this condition. It is also extremely probable in the case of a ship as light as a destroyer that if damage were received in action, serious enough to disable a blower, so much other damage would be done in any one fire-room that other like units would not be able to operate and would no longer serve a useful purpose.
On many destroyers, the economy effected by running only one blower in a fire-room had to be sacrificed because of the necessity of being ready for a burst of high speed at any time, necessitating keeping all blowers in operation.
Subdivision at the expense of reliability has, it is confidentially believed, been carried out to too great an extent in our destroyers.
Subdivision, of course, is highly justified where, for example, three units are provided, any two of which may be used for full power, but this is more in the nature of providing spares, which, if valuable, involves much added weight.
Subdivision should, it is thought, he limited to two independent units in separate compartments, each as reliably built as possible.
In the case of blowers, it is confidently believed that one large substantially built blower in each fire-room with provision made for admitting air from one fire-room to the other by means of a watertight opening in the separating bulkhead will give a greater military return for money spent and weight allowed than a greater number of smaller and lighter blowers, as they are less reliable.
The Trippe fitted with two large horizontal blowers only, had no case of blower trouble in over a year of steady operation, in sharp contradistinction to other vessels fitted with four smaller and lighter blowers.
The elimination of the dependency on circulating engines in the present new type destroyer using scoops constitutes a good step in design, as the reliability of the arrangement of supplying circulating water is almost absolute, and it should be extended as far as possible to other types of ships.
Convoying large bodies of ships, whether merchant, supply or man-of-war, will surely be the lot of destroyers, to a great extent, in future wars as it has been in this war. The importance of being surely on station and remaining on station was brought out so forcibly from the very first that reliability was the paramount consideration. The relative values of reliability, economy and speed in our navy, it is believed, has been proved by the war to be in the order given.
Oiling at sea, is of course, an accomplished fact and a well-recognized proceeding. During the process of oiling six destroyers en route to Queenstown from the Maumee, the following observations were made:
Capacity for supplying oil rapidly was insufficient. Slow speed of tanker and destroyers is, of course, obligatory while oiling, constituting a danger to both ships, and this period should be shortened as much as possible.
Oiling was accomplished by towing the destroyer alongside in the Maumee’s lee, lines being run as shown in sketch, the destroyer making one knot less speed than the larger ship.
The oil lines, two in number, were rubber or rubber covered hose run from the side of the Maumee, the bight of which was supported by a line from a boom. It is considered that the boom was entirely too short and too light. Considerable difficulty was experienced in hauling the oil lines aboard, owing to the fact that the boom was too short to keep the oil hose from trailing in the sea, the speed of towing being such as to put a very heavy drag upon the hose. This fact also made it necessary to tow the destroyers too near the Maumee for solid comfort. Booms should be much longer and stronger and oil lines of greater size.
Constant operation at night strongly brought out the fact that our lighting arrangements are not too satisfactory. Especially is this true as regards illumination of fire control instruments and concealed lighting by which spotting data could he looked up, so that proper deflections could he sent to guns, etc. It is true that this data may now he obtained from a Ford Range Keeper, but even in destroyers as late as the Dent, there was nothing hut makeshift lighting to illuminate the dial of this instrument. Lighting for such locations should he by storage battery, as the ship’s circuit is too fickle under conditions of gunfire to be relied upon.
On the secondary or auxiliary lighting circuit supplied by storage battery should he included the bridge compass, the chart- house, the director-scope and Ford Range Keeper, the magazines and handling rooms, the steering engine room and a small portable light at each tube for use in making torpedo adjustments, or else separate storage batteries should be provided for groups of lights for the above purposes.
Searchlights are not light-tight, but should be made so, in order that the light may be on and working properly, ready to flash on at a second’s notice.
Lights in officers’ desks and in the wardroom pantry and in all toolrooms, fore and aft, should be included on the battle circuits. During a night of running dark, it is certain that some papers or notes, etc., will be required, and coffee from the pantries is not a luxury, but a necessity.
Some dim lighting should be provided for illumination of fire- and engine-room deck operating gear in case of accident at night, preferably by auxiliary circuit storage battery. When this gear is to be used, it is certain that the personnel will be, to say the least, hurried, and fumbling about in the dark is not the best way to locate and operate valve wheels, upon which the safety of the ship depends.
Better hoisting and lifting facilities should be given repair ships. Booms should be heavier and longer. During the past war, there happened to be in our base ports an ample number of tugs available for handling destroyers incapable themselves of steaming alongside repair ships because of main engines undergoing repairs, so that boats not inboard against the ship’s side, could be shifted if any heavy piece of machinery required lifting. This will probably not be true to the same extent in another war where our destroyers are operating at an advance base, and not from a permanent home base as they were in Ireland and France. Four boats on each side of a repair ship is about the limit, and booms should be long and strong enough to reach the outboard boat on either side.
Our wise and foresighted policy in regard to repair ships and self-sustaining qualities of our destroyer flotillas was more than vindicated in the war. It is not thought too much to say that the repair ships abroad more than paid for themselves in actual money saved, and in military value, almost paid their weight in gold. Without these ships, there could have been no convoy system, no extended patrolling, and our boats would have lain idle for months. There is not credit enough to give the officers who directed repair work on these ships, and certainly they should be rewarded for their extraordinary and effective work by the award of the highest medals and honors. It has been conclusively proven that any amount of money lavished on this type of ship in the future will be spent to as great advantage as money can be spent.
A tremendous volume of work was handled by these ships, but destroyer operations in this war, owing to complete surface command of the sea by the Allies, was of so routine a nature as to lead to an erroneous conclusion as to the capacity of these ships for handling repairs. Such great volumes of work could only have been done because of the possibility of scheduling work. In wars to come, this will not always be the case, and more sudden demands for large volumes of work will be required as against a steady demand spread over a long time interval. This brings up the subject of greater repair facilities on the destroyer itself, except for repairs of a major nature.
All through the whole time of service at Queenstown, it was apparent that more facilities aboard ship should be provided. This will also be important where a sudden demand is made for work, even where a repair ship is present. A great deal of useful work, now impossible, could be accomplished if a suitable frame were provided for portable electric drills which would permit setting the drill to any angle and providing the drill with small milling cutters. This frame could very conveniently be situated near a boring mill table, and could with milling cutters be used in conjunction with it. As far as actual expense goes, these machines would pay for themselves in a very short time. Some method of handling work larger than can be carried in the lathes is absolutely necessary. A drill flexibly mounted, supplied with milling cutters m connection with a boring mill, would combine as far as possibility of work, a planer, shaper and boring mill.
En route to Queenstown, an incident happened on the Trip pc five-turbine three-shaft arrangement, on which ship the writer later became engineer in addition to other duties, which brought out some interesting points in connection with accessibility of parts for repair and the tremendous importance of facilities for repair aboard ship.
About half-way between Boston and St. Johns, Newfoundland, noises heard in the starboard L. P. indicated that something was rubbing badly. This engine, together with the S. I. R cruising on the same shaft, was immediately shut down. The ship was in company and in formation with five other boats. The question of going' ahead on the remaining two shafts was considered. This, of course, was done, but the point that is to he brought out is that the ship was forced to steam at a considerably lower speed than it was practicable to make, and hence, slowed down the whole six boats because of the fact that there was no shaft brake or clamp provided. Jacking gear was inserted to keep the idle shaft from turning and further damaging the turbine, and rope lashings were applied in a crude fashion around the couplings.
Some form of band brake should be provided on all ships for use in a similar emergency. The writer made a note of this fact at the time, and upon arriving in Ireland, found that in the British Navy this scheme had before then been adopted. The military importance is quite evident.
Upon settling down to new conditions, preparations were at once made for raising the turbine casing upon reaching port. The steam valve to the turbine was thought to be tight, the bolts were removed from the casing, and the exhaust trunk joints were broken. It is here noted that the section of exhaust trunk to be removed was hinged, an excellent arrangement which prevents the necessity for lifting out a heavy weight and which would have permitted this section to have been swung clear, while still underway even in rough weather. The turbine casing was also hinged, and the same applies to this arrangement. If it had been necessary or urgently desirable, it is not too much to say that the casing could have been raised at sea in this instance where the sea was very smooth. At least this hinging is important in the case of a boat where it becomes necessary to lift a casing when away from a regular base, and in the lee of an island, for example, where there was present a slight swell. This hinging, from a military point of view, is believed to be far superior to any other arrangement. With stout hinges and the chain-fall equipment supplied to our boats, there is not believed to be the slightest danger in connection with raising a casing, even with considerable motion on the boat.
Upon breaking the exhaust trunk joint on this particular trip, it was found that this section must be left not only in place, but that the joint had to be kept tight as the large valve between the M. H. P. and the S. L. P. leaked so badly that pressure was accumulating in the condenser. This also necessitated the continuous running of the circulator for this condenser which should have been entirely isolated. The importance of frequent inspection and the tightness of all valves by which the condensers can be isolated was made painfully apparent. There was no repair ship at St. Johns, and repairing these valves ashore would have consumed much valuable time. If the ship had been forced to cross the ocean or to make a long trip in this condition, it would have been dangerously handicapped.
There should be facilities aboard each boat for cutting the seats of such valves. It is believed that an electric drill fitted with milling cutters and mounted on a revolving arm pivoted at the center of spiders placed across the valve seat would furnish a satisfactory and light device for taking cuts on the seats of large valves in place. It is also believed that if an adaptation of a light boring mill with revolving table and cutters arranged at its circumference were provided, cuts could be taken off large valve discs satisfactorily. This machine would allow also the machining of much larger pieces than can be swung on the small lathes provided. Referring again to the incident cited above, it was found upon lifting the P. L. P. casing that one-half the dummy strips were wrecked. These were chipped away, bearings shimmed up, the casing closed ; and the trip across the ocean was successfully made. In this connection, it is confidently believed that the dummy strips should be caulked into both dummy piston and dummy cylinder, instead of having the piston dummy an integral part of the rotor. The damaged half of the rotor dummy strips on the Trippe, although steel, would not have operated satisfactorily, owing to irregularities, wear, etc., unless turned in a lathe. Separate strips caulked in would have permitted renewal by repair ship without the necessity of removal of the rotor from the ship. The dummies, of course, are damaged more frequently than any other part of the turbine, barring total wreckage due to loose blades or foreign articles, which damage cannot be provided against by design, purely.
Renewal of tubes in boilers was quite common, and only those types of boiler in which retubing can be accomplished without cutting out good tubes in order to insert new ones and without necessitating removal of boiler casings, should be adopted. Given this type of boiler, many of which are in use now, there is no reason why dead boilers cannot be retubed while steaming at sea.
Bulkhead joints in steam lines should be absolutely eliminated. It is impossible to keep these tight on account of play in the light bulkheads, and if these leak, stores are ruined or personnel is inconvenienced. In all long lines of piping, either expansion bends or slip joints should be fitted, but anchor engine lines are not now so installed, even in late boats, and are a constant source of annoyance. Small expansion bends, of course, involve less weight than expansion joints.
A great deal of the damage to propellers could be prevented by a better type of propeller guard. This subject is now under consideration at the Boston navy yard.
All electric motors should be installed fore and aft. Much trouble was experienced with those mounted athwartship during heavy rolling.
Switchboards should be mounted well away from bulkheads which sweat and be protected from falling sweat by metal shields. They should never be placed near a porthole or hatch where spray can get to them, due to negligence in closing the port or hatch at sea.
One of the most frequent and serious causes of defection in ships from what may be termed the front line was condenser trouble. Time and time again, boats were forced to leave their posts and return to port on account of salting up. There is just one way that this can be prevented; rigid and frequent tests of condensers in port. They can be tested at sea after leaks develop, and this has often been done, but the vacuum test is the only one available, and unless the valves between the L. P.’s and the next turbine up the line are tight, even this will cause overheating of the condenser, due to leakage of steam and lack of circulating water.
The remedy, or rather preventive measure, resolves itself then into being able to frequently apply high or nearly the original specified test pressure to the tubes before steaming commences, that is, during overhaul periods in port. It is obvious that if the condenser tubes will stand, say 900 pounds to the square inch in pressure, they are not likely to give way due to corrosion for a further period after test of many months. Those which are found defective on test would either be plugged or renewed. By this method, defective tubes would be eliminated before they gave way under steaming conditions with resulting salting up and return to port.
This test would also obviate the necessity in old condensers, when overhauled, of renewing all tubes instead of only those which are defective. The writer has designed, roughly, an arrangement by which this test can be made, and it is earnestly hoped that the department will develop either this scheme or some other, in order that “salting up” can never be given as a reason for quitting the sea. Instead of air pressure, hydraulic pressure might be applied, and in the case of a ship with condenser tubes of the same length, multiple test heads might be used. This test would not be required at very frequent intervals and could be made in several working days. (See Figs. 2 and 3.) In the case of packed tubes where ferrules are used: some arrangement of test head shaped like a plug could be inserted in the tube.
This apparatus consists merely of a fitting as shown at A, backed by a screw jack which fits between the tube sheet and condenser head. Air pressure is applied by compressor through flexible copper piping. One man at each end of the condenser would apply A and B to the ends of the same tube setting up on the jack by means of the hand wheels shown and forcing the rubber gaskets against the tube ends; another would turn the plug cock admitting pressure, and he would, after the gauge showed the pressure to be applied, shut off the cock. The rate at which the pressure fell would indicate at once any pinhole, split or1 rupture; or pressure could be applied to all tubes in order to rupture thin ones and the standard tests now in use applied later to discover and eliminate those tubes which have failed under high test pressure.
It is realized, of course, that the testing of a large condenser by such a method is long and tedious, but not more so than overcoming the effects of salting up a whole plant, and dependability of the condenser would, it is confidently believed, be almost absolute.
Economy at sea, over and above that obtained by careful operating and good engineering practice, is solely a matter of original design.
This would seem to affect in a major way only turbine and propeller design, as no combination of one' small boiler for use at very slow speeds with other larger ones, could be devised to better the present arrangement of two boilers of equal power in each fire-room, taking all things into consideration.
One large and preventable source of trouble is leakage of air through boiler casings, and this, of course, affects economy to a marked degree.
Boiler casings should be made of as few sections as practicable, in order to lessen the number of joints. There is no reason apparent for not increasing the size of the different sections, just so long as the sections are not too large to make handling impossible when they are removed for overhaul, etc.
There is at present no satisfactory material with which to stop air leaks in boiler casings. Powdered asbestos applied wet soon cracks away from the casings where applied and so does fire clay, or a mixture of the two. A mixture of asbestos and some of the ingredients of the wash, which is applied to brickwork, has been tried out by the writer, but without success. Experimentation should be made until some suitable material is developed.
The arrangement, in some types of boilers now in use, precludes keeping them free from soot, and this cuts down economy and especially on long cruises where economy assumes such importance.
In regard to speed, it is believed that the matter should be put up to the War College through an engineering member, in order that opinion could be obtained as to the merit of sacrificing full- power economy, which is seldom required, for greater economy at cruising and moderate speeds. This opinion should be given in terms of definite percentages.
Economy in port is quite as vital as it is at sea. At one time at Queenstown, there was only a small part of a tanker’s cargo of oil available, and great anxiety was felt for the safety of the next tanker; this under most ideal conditions. I wo small storage tanks on shore were put in readiness for supplying oil, but these would not be available at an advance base, and the trip to some base where they would be available would only eat up more oil.
The following is suggested as a means of greatly increasing port economy:
One generator to be oil engine driven.
One flushing pump to be electrically driven. Operation in port as follows: One boiler with steam up for cooking and heating. This requires only infrequent lighting off to bring pressure up and then shutting down. It may be accomplished by the use of a small burner tip and would require no running of steam blowers except when distilling fresh water. Then one or more large tip burners to be used with an auxiliary blower, electrically driven with a temporary air duct in use as in the closed type of forced draft blower furnishing the necessary air supply to these burners.
This boiler, which would require very little expenditure of fuel oil, is ready at a moment’s notice in case of fire, dragging, etc., where a large demand is made for steam. The oil engine-driven generator would supply all electric power and lighting, and it is known that there are such units now available in the commercial market. The electrically driven flushing pump should be of sufficient capacity to furnish the flushing system and circulating water for the distillers, as will be explained later.
While operating in this manner, there would be practically no exhaust steam, except the very small amount from the feed and fuel oil pumps or fire and bilge pumps while washing decks in the morning, and it is believed that with circulating water going through the distillers, this amount of exhaust could be easily condensed in the distillers and feed heaters and run to the hot well by gravity, there being no necessity for vacuum, as there would be no steam-driven generator in operation. This arrangement would obviate the necessity for an auxiliary condenser with its pumps and pipe connections, which would do away with a large amount of weight. In case of fire or other emergency, exhaust would be to the atmosphere. It is noted that this would be a very convenient arrangement in cases where all steam power is off the ship, while overhauling boilers, etc., at a navy yard, or alongside docks where no electric power is available.
In conclusion, apology is made for the lack of smoothness in this article, but even if crude, it is hoped that it will accomplish the purpose for which it was written, which is to give rise to helpful discussion of engineering subjects.