The last annual report of the Secretary of the Navy, for the fiscal year ending June 30, 1932, reveals the fact that the United States Navy has dropped to third place among the navies of the world. Many of our ships are old. Under these conditions it is more necessary than ever before to see that the hulls of our vessels are kept in good condition.
Naval vessels are built on the “cellular” principle. They consist of a considerable number of water-tight compartments, separated by bulkheads and decks, the idea being that if a few compartments are bilged, the buoyancy and integrity of the remainder will be sufficient to maintain the ship afloat in an upright or nearly upright position so that her guns may be served, and that she may still execute, even if in a somewhat halting manner, nearly all of the functions for which she was designed. But what if decks and bulkheads are not water-tight? Then damage to one underwater compartment may result in such extensive flooding of the vessel as to render her useless, if not a total loss. The cellular construction is, in such case, worse than useless, because it may conduce to a feeling of safety which in reality does not exist. Corrosion may so weaken or even destroy compartment boundaries that they can no longer be considered water-tight. Failure to close small holes in bulkheads, or poor workmanship may cause the same results.
Naval vessels (exclusive of side armor) have also been described as consisting of a thin, elastic membrane (the shell plating) stretched over numerous adequate supports (the frames and longitudinals). The comparatively light shell plating, that is, light when compared with the size and weight of the ship, is admittedly and designedly weak, and is not intended to possess much resistance to blows or shocks such as those caused by striking a rock or by an underwater explosion. The resistance to extensive damage is provided by the framing system. Yet pitting in shell plating may penetrate to a depth of more than 20 per cent of the original thickness. Frames, floors, reverse bars, and longitudinals may corrode away if not constantly watched and cared for, and their value as supports for the shell plating will be almost completely destroyed. Of what value is the “elastic membrane” in such cases, and what support for it is there, when the framing system is thus deteriorated?
Another concept of a ship, used in design and strength calculations, is that of a beam or box girder. The top flange is the main or strength deck, whose strength may be supplemented by that of the other decks or platforms; the web is the side plating, principally the heavy shear strake and the side stringers and longitudinals; and the bottom flange is the bottom plating and keel. Usually these important strength members are quite heavy, but any serious wasting away of the flat keel plates or the adjacent garboard strakes should be guarded against. Deterioration of the main deck definitely affects the longitudinal strength. Even an intermediate deck contributes somewhat to the strength of the ship as a whole so that care should be taken to prevent its rusting or being otherwise weakened.
I do not wish to be misunderstood. Ships are designed with a liberal factor of safety, and this is counted upon to compensate somewhat for the more or less inevitable wasting and corrosion that takes place during the many years which constitute the life of the average naval vessel. Nevertheless, all corrosion should be combated as actively and constantly as if it were an enemy of our nation.
The most common form of deterioration is the corrosion of steel. It is obvious that, given the same corrosion producing conditions, the thinner the steel, the more serious will be the reduction of strength in the same period of time. It is for this reason, among others, that the corrosion on lighter vessels, particularly destroyers, should be guarded against even more actively than on vessels of heavier construction.
It is now 1933, fifteen years since the end of the hostilities of the World War. Roughly speaking it is about twelve years since the United States stopped building naval vessels except cruisers and a few submarines. By treaty, the life of a battleship has been set at twenty years, and the life of a destroyer at twelve years. These arbitrary treaty figures are only slightly less, in my opinion, than the actual useful life of such vessels, assuming average conditions and giving a reasonable weight to obsolescence. At the present time practically all the destroyers of the United States Navy are at least twelve years old. The age of our battleships is such that more than half their allotted span of life has already expired. The probability of replacement is, in my opinion, very small. Notwithstanding the war clouds which gather from time to time, the fact cannot be ignored that the nations of the world are still engaged in efforts to reduce navies, including ours. Recently a most potent foe has entered our national life to block the construction of additional ships for the navy—the depression. I firmly believe our over-age ships should be promptly replaced—we are already years behind in that program. I also believe we should live up in every other way to our treaty ratio of 5-5-3, and I hold that every naval officer should at every opportunity point out the grave danger if our nation fails to do so. Economic conditions are such just now that there will be little if any naval shipbuilding in this country for the next few years—and it takes a long, long time to commission a ship after Congress authorizes it.
All of this is for the purpose of emphasizing the fact that it is more necessary now than ever before to keep our ships in the best possible condition. With little or no prospects of obtaining new vessels, the effectiveness of our navy from a material endurance point of view, depends in no small measure upon the care we bestow upon the ships we now have. Unquestionably any repairs now needed should be made at once, but such repairs cost money, and future repairs to portions of the hulls which may corrode to a point where repairs are necessary will cost more money. The funds to pay for these repairs come from the maintenance appropriations for the navy. Owing to the hard times and the necessity for public economy, these appropriations have been reduced nearly every year for some time past. The current newspapers state that a further cut is to be expected next year.
The operating requirements of our ships may be such as to make it impossible to devote either the men or the time to scaling, painting, and repairing to the extent desired. Any deteriorated condition, whether local and relatively unimportant, or whether more general and of serious import, can indicate only one thing neglect. Decks do not rust through in a day. If, when rust first appears, it is scraped off and new paint properly applied, and if this procedure is repeated as often as the first signs of rust are apparent, practically no appreciable diminution of strength would take place.
Care and preservation work is largely the prevention of corrosion or its arrest in the early stages. The remedy is usually scaling and painting. Working conditions are generally exceedingly unpleasant and difficult. Inspection of work performed is arduous. Nevertheless, a gang will soon learn that scraping and painting, when properly done, will probably last for at least two years, while such work if improperly done may require repetition, in some cases, as often as every six weeks.
The value of a trained permanent group of men for hull care and preservation cannot be too strongly emphasized. A comparatively small force of men under the first lieutenant, if both he and his men can devote full time to the job, could work wonders in keeping the ship well preserved. It would be well worth the trial, if personnel can be found for this important work, to see what a few hull artificers, supplemented by not more than twenty-five men of lower ratings, could accomplish in maintaining and preserving the hull structure of a battleship. This gang must be permanent, to achieve the desired results.
One aspect of the problem confronting the first lieutenant, particularly the young officer without much experience in such work is: where to look; how to look; what to look for.
In the following paragraphs will be found some answers to these questions.
Inspections.—The commanding officer usually inspects his vessel once a week, except that in the case of very large vessels only one-half or one-third is inspected at one time. The time available for such inspections is comparatively short, and it is not surprising that they may fail to reveal certain deterioration or other defects. It is not intended to criticize or belittle the captain’s inspection; it is admittedly necessary and desirable. Such inspections promote familiarity with ship arrangement and conditions, are necessary to maintain the desired standard of order and cleanliness, and have a distinct value on the personnel side. A very slight modification of the usual routine would, however, tend to insure the maintenance of the hull structure in that state of preservation which is so greatly to be desired.
It is recommended that the commanding officer allot one hour of the time he usually gives to his weekly inspection for the detailed inspection of at least one area or compartment. A very great deal can be accomplished in one hour.
This should be a surprise inspection—that is, the particular compartment to be inspected should not be announced until the moment of inspection. Such inspection should be made in dungarees, with either the captain himself in dungarees, or one or two of his subordinate officers in dungarees, to make the detailed examination of the compartment selected, in the presence of the commanding officer.
The inspection, to be of value, must be thorough. Look at and test everything. Take nothing for granted. Accept no statement that is not confirmed on the spot. Climb on boxes or ladders if necessary to reach high places; lie flat on deck to look under lockers and foundations. Don’t be afraid of getting dirty. If you get too dirty it is evidence that the compartment is not properly clean. If the captain is too rotund or too dignified to indulge in such gymnastics, the officers accompanying him in dungarees should do the work in accordance with his directions and in his presence. A yeoman should be at hand to take notes. When trouble is found in unlikely places, or when parts of the vessel or her fittings that have heretofore been taken for granted are examined and tested during such an inspection, it is practically certain that the word will be passed by “grapevine,” so that on subsequent inspections of other compartments, any previously existing deficiencies will have been remedied, or at least brought to light.
Such a detailed inspection of the selected compartment should include (1) a general examination for cleanliness and order, (2) observation and discussion of the space to determine whether its size, shape, and location are suitable for the purpose for which used. This should include lighting, heating, ventilation, access (doors, hatches, manholes, ladders), arrangement of bins, rack, stores, furniture, piping, handling arrangements, and their accessibility.
Next comes the investigation of the physical condition of the compartment and its contents. In this, nothing should be taken for granted. Test all paint with a chipping or a testing hammer. Strike it hard, because thick paint and some kinds of scale require a sharp blow to dislodge and to expose the good metal beneath. Pay particular attention to the parts that are easy to forget, the undersides of longitudinals, the tops of members that run overhead, the undersides of reverse bars, the areas under lockers and furniture. In general, select those localities that are not easily visible nor accessible, and which a lazy man would neglect. Look for blistered paint or rust streaks and endeavor to locate the cause.
Do not be afraid to rip up linoleum, to empty lockers, to knock off paint, to disarrange stores. Reluctance to spoilt the appearance of a compartment has often resulted in the progress of corrosion to a serious degree.
Sound the deck with a hammer in areas where corrosion exists or may be expected. The sound will indicate whether the deck is worn thin. In suspicious spots make drill tests to determine the remaining thickness of the metal. On steel weather decks particularly, and to a lesser degree on flat tank tops in machinery spaces, look at seam edges and rivet points. Rivet points should not be low, they should be well rounded (not necessarily high) and the edges should be solid metal. Pitting or wasting away of the rivet points appreciably reduces the strength of the riveted connection. Plate edges should not be wavy. A wavy condition usually indicates scale or corrosion between the faying surfaces. Ordinarily a number of heavy blows of the testing hammer is required to start or dislodge the rust and scale under the plate edge.
Pitting of weather deck plating occurs frequently on the steel weather decks of destroyers and auxiliary vessels. Scaling and cleaning of such surfaces, to be effective, must remove the scale and rust at the extreme bottom of each little pit, and unless the whole surface, particularly the bottoms of the pits, is cleaned to bare metal, and the surface absolutely dry, the new paint applied will not prove an effective protection. Ordinary scaling and wire brushing is usually not sufficient. A narrow bladed chisel, or a rotary wire brush, electrically driven, has been found of value in some cases.
Use a knife blade to test the seams of caulked wood decks, and to prove the existence of dry rot, which is usually first evident at butts of planking, around steel foundations or bounding angles, and in hot areas. If the knife blade sinks easily through the seam composition and the oakum, the caulking is not good, and the deck should be hardened down or recaulked and repaid. The existence of white spots along the seams where the marine glue or putty is missing will frequently mean a leaky deck, and the underside of the wood, or the steel on which the wood is laid should be examined for leaks or rust streaks. Look for scale between the stringer plates and the wood laid on them. Bulging down of stringer plates, or bulging up of the wood, are often reliable signs of scale that cannot otherwise be detected.
Sound tile and cement with the testing hammer. Use light blows and let the hammer “bounce.” A hollow sound or a marked variation in sound over different areas will indicate the probability that there is not a good bond between the tile or cement and the steel beneath. Examine the edges of cement and tile. Rust stains or the pulling away of the cement or tile from the steel boundaries almost invariably means leaks. Broken or stained tiling by no means indicates the necessity for renewal. Although the appearance may not be good, it is a waste of money to renew unless leaks exist that will cause deterioration of the structure beneath.
Note the corners, especially the outboard and low corners. If stores are in the way, have them removed. If linoleum is laid on deck, remove small pieces in such corners. Under wash basins, deck ventilators, and airports the leaking water will quickly corrode the deck under linoleum.
If linoleum is carefully cut to fit closely around pipes, deck brackets, stapling, etc., have it cut away for about six inches, and do not replace it. Keep linoleum away from all boundaries as far as practicable, and especially keep it away from steam and other hot pipes. Heat combined with moisture accelerates corrosion, and almost invariably such locations under linoleum are the first to corrode.
Remove sufficient floor plates or floor boards so that all of the structure beneath can be inspected. Usually when one section of floor boards is taken up, a brief examination will show that somewhere at the ends or sides of the compartment there will be a small wedge-shaped space, difficult of access. That is the place to examine, especially if heavy stores, of a type not frequently moved, are stored over it. The chances are that the space will need scaling and painting.
Naval paints are of excellent quality and will give good results, if used properly. It is realized that it is inherently difficult properly to clean the metal and have a dry, clean surface upon which to apply the paint. More efforts to obtain these conditions, and some ingenuity in choosing times and seasons, in proper ventilation, in the use of electric heaters, in the use of solvents to remove grease, in using electric rotary steel wire brushes, and in bringing both sides of the steel to the same temperature will materially improve the results obtained. Give the paint plenty of time to dry—until it cannot be easily dented with the finger nail. Use it thin, which sailors seem to hate to do. Stir it well, at least as long and as thoroughly as prescribed in the painting manual. The attention paid to these points at navy yards is one reason for the prevalent opinion that painting by navy yard painters is better than that done by the ship’s force.
Portland cement in bilges, unless removed once every two years or so, will tend to separate from the metal and admit moisture which in turn will cause corrosion. If unattended this may be serious. Generally speaking, tolerate only the absolute minimum of cement. In any event, remove it for examination at least once every three years. Under the cement in the “vee”-shaped pockets at the forefoot of destroyers the structure may be found seriously corroded.
Remove one or more sections of sheathing. Metal sheathing under air ports corrodes rapidly. Strike each little drain well or pocket under the air ports. If thin or corroded through, investigate further. Endeavor permanently to remove sheathing, whether wood or metal, to a height of about 14 inches from the deck, so as to keep exposed the deck at the side, the bottom of the frames, and the deck bounding angle. At least once every three years metal or wood sheathing should be removed in random locations to examine the plating and framing behind it. This is particularly desirable on Isherwood built ships where longitudinal members exist behind sheathing, because moisture will collect from leaks and condensation and stand on the tops of the stringers, which causes corrosion. Sheathing also harbors rats and vermin, and it should not be used except where absolutely necessary.
Look into all lockers, cupboards, and bins, and under and behind racks and stowage places. If such containers are fitted with backs or false bottoms that conceal portions of the ship’s structure, see that they are portable, and remove them to examine the condition of the structure.
Look overhead. When the deck above is unduly hot, paint will flake off. Note any evidence of rust, particularly around rivets, deck bolts, and seams. Comparatively small pimples in the paint with rust showing at the apex may indicate serious corrosion. Under washrooms, lavatories, and laundries look for light scattered rust spots overhead. A group of these, each not much larger than the head of a pin, is cause for suspicion. Thrust at them with a pricker or a screw driver about 10 inches long ground to a point like an ice pick. Not infrequently such a pick will pass completely through the steel of the deck above, although the surface of the paint gives no indication of trouble other than these small rust cones. Look for blistered Paint and corrosion around all pipes piercing the deck above, especially deck drains, soil pipes from toilets, and other flushing leads. Rust around deck bolts is a warning that a section of the caulked wood deck above should be removed to examine the Progress of corrosion from above. In many distances, however, these leaks are minor and are due to water leaking through the deck plugs and past the grommets at the neck of the deck bolts. The remedy is obvious.
Look at the piping. Ask what each pipe is. Note whether the piping is properly striped in colors to indicate its purpose. If not familiar with the different colors, ask about them. It is astonishing to find how many men in charge of compartments do not know the right answers. When the piping has been identified, note whether all of it that should be lagged is actually so covered. Feel the bottom of the lagging to see it if is wet. If it is, it has lost much of its insulating value and should be replaced. Look for leaks at joints and flanges. Rust at the threads of screwed piping may indicate serious corrosion of the interior. Generally speaking, however, the condition of piping can only be determined by subjecting it to a pressure test of one and one-half times normal working pressure, or better, by removing sections at random and examining the interior. At times, particularly with steel pipe, the appearance of rust cones on the outside under the paint will give a clue to the interior conditions. Such cones should be explored with a pricker, and do not be surprised if the pipe can be pierced with it.
Examine all doors, hatches, and manholes. See that doors and hinged hatches operate freely, but not loosely, and that hinges are not worn. Try the dogs and see that they are properly packed, and that they take up properly on the wedges. Look at the gaskets and see that the knife- edge impression is uniform in depth all around, and that the indentation is not too deep. Gaskets should be free from paint or other material and feel properly soft and elastic to the finger nail. Graphite and oil, automobile top dressing, or other similar preparations cause deterioration of gasket rubber. Notwithstanding the prevalent opinion regarding them, they are harmful and not beneficial. They should not be used. Test doors and hatches for warping, which can be done by closing and setting up on all dogs. If one or more dogs are unduly loose or unduly hard to set up, the hatch or door may be warped. Note the knife edges of the openings. They should be clean and smooth. Continued use of emery on them should not be permitted, as eventual wearing down in an irregular manner will occur, which will tend to destroy water-tightness. Look for scale under the wide flat rubber gaskets of flat manhole plates. See that the studs o such manholes are tight and free from rust, and that there are plenty of threads to permit setting up the nuts tightly.
Strike all vent ducts and pipes with the testing hammer, especially the horizontal leads. A clattering noise will indicate that loose scale has been dislodged. Open up several hand cleaning holes and feel the interior for dust, dirt, and oily deposit. Dirty screens, or the use of cheesecloth over terminals on discharge openings will often reveal the fact that the ducts are dirty inside. If sufficient cleaning holes are not provided, additional openings should be cut. Sound all low points in supply vent pipes. Moisture collects here, and when corrosion once starts its progress is rapid. On destroyers, although there is a large drain hole at the bottom of the intake elbow of the forward vent set alongside the officers’ ladder to the wardroom, this part of the vent piping is occasionally nothing but a mass of rust and scale. The magazine vents on the port side of the main deck on destroyers, just under the port wing of the bridge, are frequently almost completely corroded away owing to the fact that they receive considerable spray and salt water when at sea. Examine all ventilation valves, dampers, and closing devices through water-tight bulkheads or decks, and in magazines. See that they are easily accessible and in working order and that their use in battle or in case of disaster is thoroughly understood. Remove inspection plates from the motors and fans. See that the fans are clean and free from erosion, scale, and dirt. Any one of these may cause lack of balance with consequent vibration and noise. Feel the commutators and see that they are smooth, with the mica well below the bars and that they are not worn in ridges. Test the tension of the brush rigging. Operate the motor to see that there is no undue sparking, vibration, or noise.
Strike bulkheads, lockers, and bins in living and food containing spaces to dislodge roaches. A sizable roach can conceal itself effectively on what appears to be a perfectly smooth surface, but the shock of a sharp blow with a testing hammer will cause it to run and thus reveal its presence. The elimination of rats and roaches requires unremitting care and a knowledge of the habits of the beasts. Instructions along these lines are available.
During the inspection, work everything that can conveniently be worked. Open and close doors and air ports, lead out, hose, operate vent sets, open and close valves. Often appliances that look all right. will reveal defects or inconveniences in operation.
Inquire about the purpose and condition of all fittings, appliances, pipes, leads, bolts, patches, and peculiarities of structure. Such inquiries will not only familiarize the inspecting officer with the purpose of many items regarding which he may be ignorant, but more to the point, will insure that the head of department and the men in charge of the compartment know all they should know about the space and its contents.
When doubt arises as to whether any defect discovered is serious, do not hesitate to consult the staff of the force commander. That is, at least in part, what the staff is for.
A large proportion of the defects discovered can be easily and quickly remedied by the ship’s force. The tender or the navy yard may have to be called upon to remedy others. Still again, the employment schedule of the vessel may be such that postponement is necessary. Make a record of all items that have to be postponed, whatever the reason. Even if remedial action cannot be promptly taken, the record of conditions is of great value.
It is hoped that in these recommendations and suggestions there may be found enough of merit to assist all concerned in the vital task of keeping our ships, as long as they last, in such a state of material readiness and well-being that when needed they may indeed be relied upon as our “first line of defense.”