Editor’s Note. Lieut. Commander Smith was engineer officer of the Mississippi, which in the competition year 1921-22 won the prize for “Greatest Improvement,” and in the year 1922-23 stood second in the engineering competition of the battleship class. For that reason the suggestions and recommendations which he makes are entitled to special consideration.
ENGINEERING economy has made great strides within the past three years and some results have been accomplished which are worthy of record. Prior to the war period, the majority of our battleships were burning coal and the burning of coal was developed into quite an art. At best, however, the standby losses in coal-burning boilers were so large that the economies developed could not immediately be recorded in a reduced fuel consumption, and certain other economies could not be practiced because of the requirement that ample fires be maintained at all times to meet possible demands for steam.
The oil-burning battleships constructed prior to 1917 were chiefly concerned with the proper operation of the plants, which were new to most of the officers and men manning these ships. Many of the types of burners then in use have been discontinued and replaced by more satisfactory types, while fuel oil heating equipment has been enlarged and equipment generally standardized.
With the assembling of all of the oil-burning battleships on the West Coast, after the war, and the addition of the California and the Tennessee, the entire battleship fleet was composed of oil burners with the exception of the New York and the Texas. There commenced, at this time, an era of healthy competition which developed economical operation to new and unheard of standards, and increased the steaming radius of many of the ships by fifteen to twenty per cent. These economies were possible chiefly because of the flexibility of the oil-burning boiler which permits the instant checking of combustion when the demand for steam has ceased.
There is a difference between engineering economy and engineering competition—economy is absolute while competition is relative. Yet, without the competition to spur on the efforts of a ship’s company, it is doubtful if the economies could be developed to the point where they become general and of real benefit to the Navy. There are many critics of the engineering competition, but for the most part they have not been acquainted with real benefits which the “competition” has produced. It compels a closer watch upon the plant, its condition, its hours of operation, and its reliability. It is not possible, afloat, to develop a standard cost figure for power, due to the great range in operating conditions, military losses and diversity of types, but the competition does, nevertheless, furnish an excellent auditing system, stimulates the leading ships to intensive efforts and points out the laggards.
The writer recalls making a few mental reservations about a certain engineer officer of a very new battleship who stated that he was burning only ten tons of oil a day in port. Most of the ships at this time were burning thirteen to fourteen tons of oil, which was considered a good showing. After a conference on board we decided that we would try to reach this new low level. Six months later this figure was considered high, with eight and a half tons average, and six to seven tons on a holiday a bottom figure. Before discussing the causes for these improvements, it is desired to point out that engineering efficiency can be obtained without interfering with ship comfort. Probably nothing has prejudiced the minds of officers and men against the competition more than the ill-advised restriction of necessary heat, light and water. This restriction is fully justified only to prevent waste. One turns out the lights in his own home when leaving a room, and it is nothing short of indifference and carelessness which causes an officer to leave four to six lights burning in his room when out of the room. A cold ship is an unhappy ship, and the lack of sufficient fresh water is the cause of more unhappiness that we realize.
The large gains must be made below, and the engineer officer who wishes to have the entire ship’s company behind him would do well to consider their comfort.
The factors which make for economy are:
- Condition of the plant.
- Methods of operation.
- Instruction of personnel.
- Military and ship factors.
- An inspection system for items (a), (b) and (c).
The Condition of the Plant
The upkeep of the plant has always been an engineering consideration, but upkeep for economy rather than work ability requires a much closer inspection. The burner tip on a Babcock and Wilcox boiler will, for example, always function if not clogged up, and yet this tip, which closely resembles a nickel in size and shape, will if scratched or nicked, become an oil waster. These tips were inspected with a magnifying glass and discarded if not perfect. It has been found that, although water up to a salinity of 300 grains per gallon is permitted in a Babcock and Wilcox boiler, anything over fifty grains causes a noticeable increase in the consumption of oil. Also, nothing is quite so wasteful in a boiler as loose baffles. The excellent condition of the boiler is essential for the best results. Leaky pumps, particularly air pumps, are wasters. Tight valves are essential, for these mean control and without positive control the few per cent between the winner and the runner-up would soon be lost. It is not enough that the plant be in very good condition—it must be more than that, it must be excellent to win. The most effective examination for an auxiliary is to note how slowly it can be run to do its work. A turbo generator designed for 5,000 r.p.m. must have the governor set so carefully that it will not make over this speed. These few examples are cited to show what is meant by upkeep for economy. As a result, there is a second and very important economy which only develops after a ship has been earnestly at the game for a couple of years. It is found that so much less machinery (auxiliaries) is operated that the plant requires fewer repairs. Duplicate machinery is alternated in use, and many pieces of machinery have long periods of idleness.
Methods of Operation
Herein lies the great field of endeavor for the engineer officer. Due to the constant change of personnel, it is very rare to find any part of the plant being operated at its best, provided of course that the ship has not been at the top of the list. The place where the largest improvement can be made is the fireroom. “Low air, hot oil, hot feed water and correct burners” should be the slogan. There is much literature on the subject and it need only be adapted to the ship concerned. A ship cannot run smokeless and be economical for the simple reason that once the boilers go beyond the point where a slight haze is emitted from the stack—the economical point—there is nothing to measure how much excess air is being used. It is not alone the steam used in the blowers, but the cooling effect on the boiler and, most of all, the fact that as the air pressure is increased the flames passing through the tube nests are shortened, thereby reducing the effective heating surface. It is safe to say that the excess fuel for running smokeless will amount to from ten to fifteen per cent.
A standard method of operation should be worked out for each station, and when once accepted as the best method should be printed, if possible, otherwise typed, framed and posted at the station. It should state actual pressures and temperatures so that no excuse can be offered by the watch standers. It also serves to preserve the efficient operation of the station against changing personnel. The time selected for testing operating methods and changes should be the midwatch. Nearly all midwatches in port are alike and the same machinery is usually in operation. By shutting down the ice machine for four hours the exact amount of oil which it requires can be ascertained by the saving shown over the previous midwatch. In this way the additional fuel used during any hour of the day can almost always be definitely placed. The same applies at sea, steaming in formation. At this time all variables, such as maneuvering, operation of turrets and large changes of speed, are removed and the operating conditions are very much the same, so that any changes in method can be tried out and the difference in fuel consumption charged to the change. As is to be expected, much higher scores can be made during the night watches than can be made during the day watches, but with the exception of the maneuvering hours the score for any hour of the day bears a very close relation to the same hour of the preceding and following days. This is extremely valuable in making comparisons and in locating losses, and is much better than comparing the hour with a different hour in the same day’s work. This is possible on a cruise of over three days’ duration. The score comparison is made rather than the fuel comparison because the standard speed may have been changed one or two knots.
It may be of interest to mention a few of the operating conditions developed which will reduce the fuel consumption. Probably most of them are now in general use, but one or two of these items may prove of benefit to some ship.
Port Operation
- Burners. From 4 p. m. to 7 a. m. use the smallest tips available. This will require resetting of burners as far out as possible. Lower air pressures can be used but more burners will be required, sometimes all of them. Regulate the steam generated with the pressure of the fuel oil lines rather than cutting burners in and out.
- Boiler Pressure. Drop in port to the lowest pressure possible. This is determined by the highest pressure required for any auxiliary. If the boiler safety valves are set for 275 pounds and the steam for the generators is reduced to 150 pounds and this is the highest pressure required, then drop the pressure on the steam lines and the boiler to 150 pounds.
- Blowers. A great many large blowers may be cut out. The gunnery officer of my last ship was not only willing but requested that magazine blowers be stopped, except for occasional use. He stated that the constant pumping of cold air into the magazines was not good for the powder. This is only practicable when these blowers do not supply other spaces as well. Having served a tour of duty as proving ground officer the statement of this officer has weight.
- High Pressure Traps. All of these were by-passed, and never used. The high pressure drain line under full boiler pressure was run to a high pressure seal close to the feed tanks. If a ship is not so equipped, it should ask for this change as it is worth one ton of oil per day. It consists of a cylinder similar to a kitchen boiler, built to stand boiler pressure. The high pressure drain line runs in at the bottom and a water level is maintained in a guage glass by a discharge valve which connects to the feed tank through a check valve.
5. Small Turbines. The second and succeeding nozzles are never used until after the steam throttle valve has been opened wide for the first nozzle. In fire room operation, it has been found that two blowers using one nozzle each are more economical than one blower using two nozzles.
6. Augmentors. If a 28-inch vacuum can be maintained on a single generator without augmentor steam, much economy will result. This is possible during periods of light load if the air pumps are in good condition.
7. Back Pressure. If the evaporators are operated on exhaust steam there should never be any occasion for operating a condenser. If the back pressure is habitually over fourteen Pounds in port, either the auxiliaries are in poor condition (causing excessive speeds in addition to leakage) or too much machinery is in operation at one time. If the back pressure is too high on occasions, look for open valves and hot pumps not in use. The back pressure is too low, that is, lower than is customary, look to the spring loaded exhaust valves to condensers and for warm condensers. Low back pressure reduces the output of the evaporators and lowers the temperature of the feed water.
8. Ice Machines. An intelligent study of ice-box temperatures may permit the ice machine to be stopped four hours per day (midwatch). Ice box temperatures below twenty-four degrees F- are not necessary. A small electric fan on the floor of the meat room will circulate the stagnant air and noticeably drop the temperature. Scrape off the snow and ice occasionally. It is pretty, but remember that Eskimos build houses of snow and ice.
9. Smoke Watch. A member of the engineer’s force at the smoke indicator can save many gallons of oil by pre-arranged signals, meaning “Too much smoke,” “Just right,” “Clear stack.”
10. Valves and Flanges. During the navy yard overhaul, the ship’s company should overhaul every valve in the department, for tightness, as this cannot always be done when the ship is operating. Every leaky flange should be repaired as soon as noted, as the loss from this source is very great if allowed to continue. Leaky joints are visible evidence of careless engineering.
Sea Operation
- Firerooms. It was found more economical to steam with extra boilers than to use just enough boilers to make the standard speed plus two knots. The use of smaller or middle size tips permits a lower air pressure, and the economy and the efficiency of the boiler is greater when not steaming at full power. As between using six boilers in two firerooms or seven boilers in three firerooms, the former is preferable; but where additional firerooms are not involved, the greater number of boilers is preferable. If all burners are not being used, large tips can be installed in the wing burners for emergency use. It is desirable to shift entirely to the larger tips at 7 a.m. for maneuvers, for although the full speed may be only two knots greater than standard speed in the signal book, the experienced engineer officer will always have an additional two knots available. Closed burners use no oil. There is then less chance of smoking when extra speed is demanded.
- A smoke watch at sea was maintained in the foretop during daylight hours. A smoke indicator located at this point was modified to show the boiler numbers instead of the descriptive signals, such as “heavy smoke,” “light haze,” etc. The divisions in the smoke pipe permitted the offending fireroom to be easily identified and by an approximation the actual boiler could be nearly always picked. It usually happens that all boilers in a fireroom smoke at the same time, due to the air control. The advantage of this method is that it does not disturb those boilers where correct combustion is taking place.
- Main Turbines. In velocity or velocity-compounded turbines as few nozzles as possible should be used up to nearly the maximum effective throttle opening. This is determined by the high pressure chest pressure which should be as near the line pressure as possible. If too many nozzles are open the chest pressure is lower for any given throttle opening and the nozzles are not as efficient. To operate in this manner requires an alert personnel, because the men are prone to open extra nozzles to be ready for extra speed at the throttle. There should always be about half a knot on the throttle without touching the nozzles.
- Condensing Plant. The condensing plant is a source of great waste if not watched, owing to the size of the units involved. Where a cross connection is fitted to the air pump suctions, one air pump will handle all condensate for speeds which can be made on slightly over half the boiler power. This is about sixteen to seventeen knots. In determining the lowest point at which the condensing auxiliaries can be operated, start cutting down the augmentor until it affects the vacuum, then raise it only enough to hold the vacuum, but no more. The same procedure is then followed with the air pump. The speed of the circulator should be governed by the temperature of the injection and the discharge. Where the injection water is around fifty degrees F., it can be discharged at seventy degrees—well below the temperature of any attainable vacuum—but when the injection is about eighty degrees it should be discharged at eighty-five degrees F. or eighty-six degrees F., the temperature of an attainable vacuum. The circulators are run at over twice their normal speeds in the tropics and, when full power is made in the tropics, the vacuum is poor and costly in fuel.
- Gland Steam. This is a source of waste of power and fresh water. Connections should be made to supply this steam from the auxiliary exhaust if possible.
- Warming Up. By the adoption of a printed time schedule for each operation, typed for the actual clock time for that day, much unnecessary idling of machinery can be stopped. By sending copies to all stations each time the ship gets underway, complete understanding and co-operation are insured.
- Low Speeds. The economy of operating on the excess auxiliary exhaust is well known. At low speeds the auxiliary exhaust can be admitted to the first stages of the turbines, and at a speed of four or five knots the main throttles can be entirely closed. The speed thus made is a clear gain as the exhaust would otherwise be discharged to the condensers. The maintaining of the high vacuum on a turbine installation requires the operation of large auxiliaries which cannot be stopped even when the engines are stopped, except when at anchor. If conditions permit, it is more economical to steam at four knots on auxiliary exhaust than to stand-by with the engines stopped. The reason for this is that, when the ship is stopped, the excess auxiliary exhaust enters the condenser at a pressure of about fourteen pounds gauge and at a temperature of 248° F. If this steam has been worked through the turbines it will enter the condenser at 77° F. for a twenty-nine-inch vacuum, and will permit the condenser auxiliaries to run at a much slower speed.
- General. In establishing the economical speeds of auxiliaries and the economical settings of fireroom equipment, it can be readily seen that speed changes require a complete readjustment. If these changes are frequent it means that for a considerable time, while the changes are taking place, the plant is not running at its economical point. It takes about ten minutes to adjust for economy after a speed change.
- One Engine Operation. If a ship is acting singly, speeds from five to nine knots can be made more economically by using only one side of the plant with from five to seven degrees of rudder. To be of any advantage, the auxiliaries on the stopped side must be shut down. The revolutions required on one engine are approximately fifty per cent more than the average revolutions for any speed for all engines. At about nine knots, the fuel consumption becomes greater and this method of operation is disadvantageous. It can be used, however, if it is desired to repair a leaky condenser while underway. One engine operation while towing targets is very economical. About sixty-five per cent of the normal fuel consumption will be used at five knots.
Instruction of Personnel
It is one thing to repair the machinery and develop a standard operating practice, but no satisfactory operating condition can long be maintained by the officers alone. It is essential that the intelligent interest of the enlisted men be secured, and the first step in securing their interest is to instruct them. Men do not like “school,” much less do they like “inspection.” By securing the assistance of the commanding officer, it was arranged that on Saturday morning he would first inspect those engineers due for instruction. They were then marched to the point of instruction, where officers, who had prepared their subjects, talked to them. The instruction given had immediate application to the work in hand. The men were shown burners, registers and tips, and these were explained, set for operation, cleaned and shifted in their presence. Discussions on vacuum or turbines were held for the men in the turbine division. The subjects were numerous, but always of immediate practical interest. The competition rules were explained and a ten-foot blackboard was covered daily with understandable data on the previous day’s work. Many officers voluntarily attended these lectures.
Military and Ship Factors
The interest of the captain, the heads of the departments and the watch officers is essential to win any competition and to promote economy. The captain by his attitude sets the example for all the others. If he lacks interest it will be hard to secure the other officers. The captain can help in innumerable ways I have twice been saved a penalty when the electric circuit breakers blew, by the quickness of the captain in shifting to steam steering without having to fly the breakdown pennant. He can set a convenient speed when acting singly, or he can back less vigorously that he might otherwise do upon anchoring. Some will immediately object to this, saying that it hampers the handling of the ship, but a captain “knows his oil” and is not going to let e competition interfere with the handling of his ship. Let me cite an example of what is meant. A ship may steam for half an hour at eight knots and make one hundred per cent, and on the hour, shift to a speed of sixteen knots and also make one hundred per cent; but the average for the hour is twelve knots and, because the fuel consumption does not vary directly with the speed, the amount consumed will be far above that allowed for twelve knots and the score for the hour, which cannot be split, will be somewhere around eighty per cent. This, of course, is “competition” rather than economy, but it all counts, and cooperation and understanding help. The first lieutenant can snug up his anchor chain after general quarters when he knows that a second generator is still on the line and is soon to be disconnected. The gunnery officer can come around at 9 a. m. and say that he is not loading that day and that one generator will be enough. The navigator is the engineer officer’s best ally at sea and can help in innumerable ways, chiefly by keeping the engineer officer advised of prospective changes.
On the cruise to Panama the deck watch officers staged a good- natured competition between themselves on the score for the watch, and were decorated each day at lunch by the engineer officer who had some spare cloth “Es” used as sleeve marks by the men. In port the watch officer, in co-operation with the engineer on duty, can do much to reduce peak loads. These are costly because they involve starting up units for a short period of time.
The interest of the division commander is a valuable asset. His interest in engineering must beget the interest of his commanding officers, if it does not already exist. One division commander of the battleship squadron placed his four ships, one, two, four and five, in last year’s competition. Consider for a moment what this means to our Navy when measured in terms of smart engineering performance and fuel economy. It was not a coincidence, but was accomplished by an attitude of unusual interest, support and encouragement. In this division, engineering was no step-child, but had come into its own.
Inspections
Every system where detail is important must organize an inspection system to insure the proper execution of these details and to bring under observation any unsatisfactory performances. The inspection of an engineering plant should provide for routine personal inspection and a set of daily and hourly records for each station which can be studied in detail.
The port inspections are made by the duty officer and his assistant, and by one chief machinist’s mate, one chief water tender and one chief electrician. Their inspection cover the entire plant and are made as follows: An early morning inspection, an inspection after working hours, an inspection after dinner and a late evening inspection. The subordinates report in person to the duty officer at the specified times at some designated place, usually the log room. At these times operating irregularities are discussed and the causes for excessive fuel consumption determined and corrected. Each officer and duty petty officer inspects in accordance with detailed instructions, which are printed and posted. The fuel consumption is reported hourly and recorded on a form so arranged that a quick comparison with the same hour on preceding days is possible. The day’s fuel consumption is kept down by carefully watching the hourly consumption. It is not enough that each day’s fuel report be scanned, because the rates of consumption are so markedly different over the different hours of the day that the excesses must be definitely placed. The kilowatt load per hour as shown by the watt hour meters is the quickest means of checking up on the electrical auxiliaries in use.
'The quick response of the enlisted personnel is assured when they know that the supervision is active and thorough. It matters not how thoroughly the operating methods have been worked out; if their execution is not constantly checked they will lapse into a careless performance. It is everlasting thoroughness that insures economy and not an occasional fine performance. A gallon of fuel on a midwatch counts for as much as it does on a full power run. By this careful check it is possible quickly to locate the cause of the increased fuel before it runs into a matter of hours. It is the time element which multiplies the excess.
The records should be kept for each station on a daily log sheet designed for that station. It should not be burdensome but should record, at least once an hour, all the useful data; particularly pressures, temperatures and meter readings. It is kept in pencil and not copied. Before being placed on its file in the log room it should pass the inspection of the engineer officer. It should contain nothing but active and important data. The data on these forms furnish the material for suggested operating changes and furnish the engineer officer with a secondary inspection system.
The sea inspection is simpler. At the end of each hour the watch officer collects his fuel-oil meter readings, and with the fuel allowances for the average speed for the hour, works out his score. If he uses the exact allowance the score is one hundred per cent; if the consumption is greater than the allowance, the score is under one hundred per cent. This should be enough to start an investigation as to the cause. It is usually found to be: excess air, low feed water temperatures, cold oil, poor vacuum, or excess speed of auxiliaries. The sea performance as well as the port performance soon becomes so well standardized that the defects stand out prominently in relation to the normal operation of the plant.
The officer of the watch is held accountable for the results attained, and his watch standing, therefore, becomes more than the successful mechanical operating of the plant. It is not possible for the officer of the watch to have all engineering stations under his immediate observation, but if the communication system is well manned the necessary information can be promptly obtained and the watch officer kept fully advised.
General
As a result of the interest in economy, there have been developed a number of electrically driven auxiliaries for port use, and all capital ships will be equipped with these auxiliaries. Their use is more economical because the water rate of the turbo generators, operating under high vacuum, is very much lower than the direct steam driven auxiliary operating against a back pressure and having a high water rate. The electrical auxiliaries provided for port use are: fire and bilge pump, fuel oil service pump, and boiler feed pump. They are provided with a storage battery, capable of operating them for a reasonable period of time, in the event that the power fails.
The installation of the new low pressure evaporators has proved very satisfactory and is supplying sufficient water for all needs. With the installation of the electrical auxiliaries, however, there is less exhaust steam to operate the evaporators. If the Diesel generators are universally adopted in the Navy there will be no further need for a boiler for port use, and it will be necessary to provide a small donkey boiler for supplying steam to the evaporators, for heating the ship, and for supplying steam for cooking purposes.
The interest in economy has reduced the size of the Navy’s fuel bill, has permitted the ships to do more steaming, and has increased the steaming radius of the battle fleet.