ON TESTED IRON AND SHIPS.*

By J. E. SCOTT, Esq., Member.

[Read at the Seventeenth Session of the Institution of Naval Architects, 6th April, 1876; JOHN SCOTT RUSSELL, Esq., F.R.S., Vice-President, in the Chair.]

THE amount of discussion which has taken place lately on this very important subject has induced me to bring this Paper under your notice. Besides being of opinion that a matter of such vital interest to the public generally, and to naval architects in particular, would be placed on its proper footing by being discussed by practical men, I think we may profit by the interchange of ideas which a discussion of the Paper may tend to elicit. There have been so many proposals of late as to the testing of iron, that one is not at all sure of the ground he stands on.

In order that every one may follow me, I have here the Admiralty's latest tests, from which you will see at once the various modes they have of testing their iron. I also give you in Tables a list of some tests we have lately made on the Clyde of the kind of iron called common ship iron, as well as of some of the pieces actually tested, from which you will see the quality of the iron used, and which has been taken promiscuously from the common ship iron of vessels now building in my yard at Greenock. But even after undergoing all these uncommonly severe tests, I should have no more confidence in it than if it had never been put under a hammer, because, if you put a sharp man who knows his business at the testing, he will put almost any bar or plate through. For instance, take a bar of angle iron, and if you want to test its ductility, you have only to take the part for testing out of the centre of the bar, and this part, I can assure you, will pass almost any test you can put it to. The cause of this is obvious to any one who knows anything about the making of iron. When a bar is put through the rolls, of course it comes out red hot, and the cooling begins first at the end and gradually comes towards the centre; thus the iron in the centre of a bar is much softer than at the ends, because it retains the heat so much longer, and is on that account the most ductile.

* Received 2nd April, 1876.

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Again, if you want to test the tensile strain, you have only to take the testing piece from the end of the bar, where it first began to cool. This will, of course, be the hardest; and you will find the very same results in testing the very greatest tensile strength. The same course holds good in any iron plates-bulb, tee, or channel iron. For this reason I have no faith in tested iron in the sense of the word: in fact, I hold this mode of testing iron to be a mere farce, and nothing more or less than an annoyance to every one in any way connected with shipbuilding, and to be in the long run productive of no better results than could be brought about in the absence of these so-called tests. In this opinion I am borne out by a gentleman who is generally considered to be an authority as to iron testing. I mean Mr. David Kirkcaldy, from whose letter to the Board of Trade on the subject of testing iron, of date 14th May, 1875, No. 188, p. 102 of the Blue Book issued by the Board of Trade, I have extracted the following:"The Admiralty mode of testing, by bending to various angles hot and cold I consider "unsatisfactory, as so very much depends upon the mode of treatment and the skill of "the workman; and besides adding very materially to the cost of testing, it is in reality quite superfluous."

The proper tests, in my opinion, are those that every pound in any properly built ship has withstood, viz., the working of each piece. Any one who is an advocate for tested iron according to the Admiralty schedule has only to spend a few weeks about the construction of any vessel, he will then see the torture that every part has to undergo. Where the trouble lies is, that those parts that turn out bad are not always rejected, but patched up and passed off. We hear of iron being rejected because of the test piece having turned out laminated, while ten chances to one it is the fag-end of a bar that has been taken to the test. What I mean by the fag-end of a bar is that part that has passed through the rolls last, and by the time it has got through is not in perhaps the highest welding heat-therefore it becomes laminated, or inclined to separate into different layers. Then we have another lot rejected because of having too much crystal, and you will see some men looking very wise when examining a fracture, and will give you an opinion that it is very good or bad as they think, without regard to the circumstances under which the fracture took place; while every one knows that a bar broken with a heavy blow will appear quite short and crystallised, while the same bar broken slowly or with several blows will show very reedy, or one part drawn away from the other and with no crystal whatever. Another difficulty in taking tensile tests is, that one man will put through a lot of iron while another man will reject the same, for the following reason.

The sketch shows a piece of iron to be tested for tensile strain. Of course to test this fairly, the centre of the holes A and B must be in the exact centre C of where the fracture is to take place; if this is not the case, or if the centre line drawn between

A and B happen to be placed in the very slightest on one side of the section at C, then we shall find that the iron will fracture with several tons less strain per square inch; because the centre of strain being nearer one edge than the other brings an unequal strain on the piece, or an increased strain on the edge it is farthest from, and thus brings, instead of a fair tensile strain, a racking or twisting strain, which it would be almost impossible to detect, and thereby the iron is condemned.

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Tested iron has been used in many cases in the Royal Navy-with what better result no one has ever heard, only that it helps to enhance the cost of the vessels to an enormous extent; and if this tested iron clause becomes law it will only help to make ships thoroughly unseaworthy from a mercantile point of view, and instead of being, as we now are, the first mercantile navy in the world, we should be gradually forced from that proud position by the vessels of other nations, whose builders and owners had fewer restrictions. Now the first question that arises is, What is to be gained from this tested iron? In reply, all I can say is, more rust and corrosion-a ten times quicker deterioration; because it is a well-known fact that the finer the quality of iron the more readily does it corrode. This finer quality of iron will be sure to be used by makers to insure their iron always going through, and thereby insuring them against an unfair test, as the first cost of this fine quality will not be equal to the greater price they get for tested iron. In cast iron we have little or no diminution from oxidization, even when exposed alternately to wet and dry.

But from what does all this excitement on the subject of tested iron arise? Have we found the ships now afloat built of common iron, as it is called, to be bad? I think not. There is not a single case on record where a vessel came to grief through the iron used in her construction being bad. If this were the case, what should we have to say to Lloyd's and the other Registries, who know all and everything that can be known about iron ships? What are we to do with all their experience from 1838-9, the year in which the Sirius and Ironsides were built and classed, down to the present time, if they had found the quality of the iron used defective? Could they possibly have gulled the public so long by allowing bad iron, and do so still? I think the gentlemen connected with these Registries will bear me out in this, and also that when bad iron ships do turn up it is from corrosion and neglect, when they get beyond the reach of those Registries and are too good to be classed.

The decay and neglect that goes on in some vessels of this kind is beyond conception, which you may see for yourselves from specimens I have here, taken from vessels of one of the first lines that carry our mails and commerce. I have also been told by a gentleman of the highest standing in classification matters that a large vessel at Liverpool

cost over £1,000 the other day to have her scaled or chipped; this, of course, was occasioned by the neglect and carelessness of those in charge. On hearing of this case from my friend I asked how was such a thing allowed to go on in large vessels like this. He then informed me that this was by no means a single case; and that a very great number of the large ocean steamers were allowed to go to ruin in the same way, simply from being run so hard, and no time being allowed to have the vessels properly cleaned and painted.

Some will say that this corrosion will go on even under circumstances in which the greatest care is taken. But such is not the case, as I could point out very many cases of box keelsons, and box waterways, and other parts little used, being opened after a lapse of from ten to fifteen years, and the paint inside being as perfect as the first day, and no decay whatever. This at once shows that the cause of all this decay is not from the quality of the iron, but from downright neglect. And are we, then, going needlessly to increase the cost of our mercantile navy 15 to 30 per cent. as an experiment, simply because some ships are neglected after the Registration Committees and builders have done everything in their power to make good ships? Is it not very common to hear shipowners say there is no fear of dry-rot in iron ships, and that therefore they will not need half the attention of wood ships? But I have simply to warn them that if an iron ship is not thoroughly looked after-and this is more apt to be the case every day, now that we are getting them introduced into almost all the rougher trade—the repairs to put her straight will cost far more than those of a wooden ship which has undergone the same amount of deterioration.

The other cause of bad iron ships, and one which I think the most serious of all— and in that I am sure you will all agree with me-is bad workmanship. This is a very grave point to touch upon, but to keep it in the background is impossible. Everyone in the slightest degree acquainted with ships knows at once the differences that exist between vessels holding the same certificates of classification; it is the exception when we find a vessel with a second-class certificate; in fact, we may safely say that there is not a single sailing ship at present building or that has been built during the last few years that has not the very highest place in the classification books. (The second class is principally held by steamers for a particular trade and of extreme dimensions, for if put into the first-class they would have to be made extremely heavy, and their dead-weight capacity would be considerably decreased.) But what do we find? That they are really as unlike one another as possible. The difference is not apparent when the vessel is finished, fitted out, and ready for sea; it is after the end of a first, second, or third long voyage that we find the cloven foot beginning to peep out. After the strain and pressure of storm and dead weight through that period has been sustained, we find a very little

slackness here; a little showing of butts at the sheer strake, bilge keel and stringers; deck seams, which we find on examination to have little or no oakum in them, and which of course allow the water to get at the stringer-plates, beams, &c., and at once decay sets in. Again, we find ceilings only half bolted, with seams you could put your fingers through, but for the accumulation of dirt that prevents it; cement that has only been half put on at first; we find a mass of sand and mud choking the limbers; and that which was to have preserved the ship is the first thing to advance her ruination by the rolling from side to side of the débris. Then in the ends of the vessel what have we? Scarcely a landing or a breasthook that has a sound rivet in it. It has often been necessary to almost re-rivet and fit from the main deck to keel, and have extra fastenings put in, to make up for their apparent weakness, which in nine cases out of ten is caused by bad workmanship.

There are vessels at this moment on the Atlantic service doing the same work, carrying the same cargoes, and of identical dimensions-the one what is most properly called a weak vessel, and the other strong and staunch. Let us look for a moment at their construction. What is found to be the weak vessel has inch in some parts, and

inch in others more plating, inch more frame, and reverse inch on floors, and keelsons proportionately stronger; in all about 10 per cent. more iron, nearly equal to 100 tons and yet there is found the greatest possible difference. The light ship has never shown a weeping rivet, or marked a butt, while the other is constantly being caulked up and fixed off, and undergoing some repairs or other; and her sister ship has not had a rivet taken out or caulking tool applied in the ten years they have now been at work. All this weakness is from defective workmanship. In the light ship every rivet was as sound as a bell, not a single jar could be felt. This can only be had when the plates are properly fitted, and not thrown on-this is the only term I can apply to the fitting, so-called, of some vessels. In the bad vessel there never was that amount of slackness that would enable you to condemn the riveting, fitting, &c., thereby enabling the vessel to be handed over; but still the weakness was there, and could be at once appreciated by a man who knew what work is.

We hear every day people say they think vessels are far too light now to what they once were in the classification books. This is not the case, I can assure you; it is. a perfectly false impression, as will be seen from the Paper read here last year by Mr. John. Since then I have worked out many cases, and have found them coincide with his estimate; and I believe this diminution of weights might still go on if we were to get correspondingly greater care of our ships from decay and conscientious workmanship. Now, from all that has been said in public and private on this matter of testing iron, it is quite clear that there is a screw loose, or rather there is one