IT

one.

LONDON, FEBRUARY 1, 1897.

T would appear, from the practical discussion, ensuing in the Shipmasters' Society on the able paper upon the legal duties of the shipmaster at home and abroad, which was the basis of an editorial note in our December issue (the said paper was contributed to the society by Benedict W. Ginsburg, LL.D.), that the practical state of affairs affecting the duties of ship-masters differs considerably from their theoretical legal position as is laid down. In the opinion of Capt. Chandler, the financial part of a shipmaster's duty is almost a thing of the past, but in many instances his present position is a humiliating He is made the butt and target for everyone's delinquencies. With regard to the cargo, the shipmaster has to satisfy three conflicting interests: that of the shipowner, the owner of the cargo, and the buyer, and apparently no amount of tact will enable him to satisfy all three. Hence we presume, like an arbitrator, he must consider he has most impartially done his duty when he has somewhat dissatisfied all. As Capt. Chandler says, this appears to be an unfortunate state of affairs, but we presume ship-masters get used to it. Capt. H. S. Thompson also feels very strongly that there is practically no way in which discipline can be legally and readily enforced in the Merchant Service, and that masters are very often obliged, where urgent and unexpected need arises for special and unusual services, to use means which have never been contemplated by statute, and which might even not seem legally reasonable. As a case in point, Capt. Thompson instanced one where a passenger had to be isolated in consequence of an outbreak of small-pox, on which it became necessary to isolate another man to look after him; no one would volunteer, so someone had to be forced to do it. This was apparently outside articles of agreement, or foreseen legal eventualities, but it had to be done. The stewards were pressed to provide a volunteer, they refused, and it was only after they had been claimed up all night and part of the next day that eventually one of them volunteered. Captain Froud points out that too often by a clause in charters arranged between owners and charterers, the master is compelled to be guilty of illegal acts, in the form of signing bills of lading, where if anything eventually turned out wrong, the action of the master might be characterised by the judges as fraud. This is a point that such a society as this might well agitate to have amended, since also such amendment that no goods should be signed for, that are still in the warehouse, but only when in possession of the steamer,

protection for bankers, whilst keeping the master on the right side of the hedge, and no inconvenience to anyone except to those who may be financially sailing too elose to the wind. As the newly-elected President, Sir Chas. Dilke, said in conclusion, "The ship-master comes more in contact with the law at any turn, than any other profession, with the possible exception of the mine manager." The valuable paper by Dr. Ginsburg had brought out some most interesting points as to the dilemmas of masters, and the moral of it was, that ship-masters should combine and discuss to raise their status, and define their responsibilities. ALTHOUGH the Bazin Roller boat has been what we should consider a long time building and completing for sea, we are not to be allowed to suppose that the undertaking is abandoned, or that the inventor and those interested in the novel undertaking have in any way lost faith in the coming success of their enterprise or in their hopes that the vessel will develop at least double the speed of an ordinary steamer of similar displacement and engine power. We had pleasure in hearing the latest details of the progress of this enterprise set forth by Mons. Emile Gautier, on behalf of the inventor, in a paper read on January 20th, before the Society of Arts, a society which has always given encouragement to the ventilation of all novel and scientific enterprises from whatever source they may come. The reader of the paper somewhat disarmed criticism by stating that he was neither a savant nor an engineer, but merely a journalist, who, however, has somewhat signalised himself and his journal by a speciality in the popularisation of scientific questions. Under this head we consider his paper to have been an undoubted success in giving a graphic and interesting account of the Roller boat, its progress, and the hopes that are based upon its completion. The boat now built and being equipped at Rouen,the Ernest Bazin by name, has a displacement of 280 tons, with length of 131 ft. 3 in., beam 38 ft. 8%, in., and is mounted upon 3 pair of roller discs of 32 ft. 10 in. diameter, with a thickness of 11 ft. 9 in. at the hub, hollow and divided into watertight compartments, and which, to give the necessary displacement, sink about one-third of their diameter into the water, that is, have a draught of 10 ft. 11 in. The engines, boilers, cargo, coalbunkers, cabins for passengers and crew are all placed upon or under a wide platform mounted upon the axles of these discs. Interesting particulars were given of the first experiments and deductions made. by the inventor that the method of progress over the surface of water with a given displacement was most effectually accomplished by the horizontal propulsion of a disc, partially immersed in water,

cannot be denied that the new Roller boat offers an entirely new problem to the naval architect and marine engineer, and that we shall thus be all extremely interested as to the results of her trials.

fore concludes that water friction in such a roller boat may be regarded as a "quantité négligéable." quantité négligéable." Were this the case and no other drawbacks consequent upon this form of construction, it would appear to be indubitable that an enormous speed could be attained with little propulsive effort, but we cannot go so far as to admit the elimination of water friction. The sides of the discs, though they have no forward movement relatively to the water over which they are rolling, must by their immersion have a descending movement at the forward portion of their side faces and an ascending movement at their rear faces, and, as the sum of the immersed volumes of the discs must be equal to the volume of the immersed portion of the hull of an ordinary vessel to give the same displacement, and by their division into six distinct hulls must have a greater surface immersed area than that of an ordinary hull, we doubt whether the skin water friction of the sides of the discs will not be as great as that of an ordinary hull, and will, of course, increase in proportion to the velocity of the rotation of the discs, which is a measure of the speed of the vessel. In fact, their action reminds us of that of a disc churn, in which the friction of the disc upon the cream is relied upon, and very successfully, to make the butter. Assuming, however, that the hopes of the inventor are realized, that the water skin friction of immersion is reduced to a very small amount as compared to the ordinary cleaving friction, it appears to us that no regard has been paid to the necessary introduction of solid axle friction, following the support of the whole burden of the ship upon 18 or more axle bearings upon the 8 in. shafts of the six discs. Such axle friction we know in the case of rolling stock of the most perfected design to represent about 9 lbs. tractive effort per ton of superior incumbent load, and as the Bazin is said to be of 280 tons displacement, some of which, however, is represented by the discs themselves, it would appear to us that there is a tractive effort to be obtained from the engines of some 1,800 lbs. to merely overcome the frictional resistance of the disc bearings, which at any rate is a new resistance in substitution of the ordinary skin water friction, which, it is hoped, has been eliminated. However, it

S.S. "CALAIS."

N our issue of August last we gave a full-page plate of Messrs. William Denny & Brothers, and engined by Mesars. Denny & Co., of Dumbarton, for the London, Chatham & Dover Railway Co., for their cross-channel service between Dover and Calais, and in this number we have pleasure in presenting to our readers an illustration of the engines as they appeared in the erecting shop of the builders. As will be seen from the illustration, they consist of one set of triple-expansion diagonal engines, which are supplied with steam by four tubular boilers, at a working pressure of 150 lbs. per square inch. The cylinders have cast-steel pistons and forged-steel piston rods. The high and intermediate pressure cylinders are fitted with piston valves, while the valve on the low-pressure cylinder is of the usual double-ported type, with an equilibrium ring on the back. The connecting rods, caps, and bolts are of ingot steel, and the crank pin brasses are lined with white metal. The valve-gear is of Mr. Brock's special design, with cast-steel rocking quadrant, arranged so as to keep the lead constant for all grades of expansion. All the shafting is of ingot steel. The engines are controlled by Brown's patent combined steam and hand-reversing gear, and the steam is regulated by a large double-beat valve, worked by screw and lever gear worked from the starting platform. The paddle-wheels are fitted with steel feathering floats, and are of great strength. Two independent centrifugal pumps are fitted for circulating purposes, and are capable of drawing water from the bilges if required. The feed pumps consist of a pair of Weir's direct-acting pumps, discharging through a feed filter. The boilers are of steel, with Fox's corrugated furnaces and iron tubes. They are worked by forced draught on the closed-stokehole principle, air being supplied by two fans. The base of the funnel is fitted with Denny & Brace's patent apparatus for catching the sparks and ashes, which are a source of annoyance and discomfort in most steamers having a forced draught.

"Clutha Composition."-Messrs. The Glasgow Patents Co., Limited, inform us that their Clutha Composition, which they supply for ships' holds, is absolutely safe to store in any part of a ship, there being no volatile spirit of any kind used in its manufacture.

Refrigerating Plant.-The trade in ice-making and refrigerating machinery continues to make rapid progress, and during the past year nearly 300 machines on the Linde system alone have been sold. This brings the total deliveries of these up to about 2,900 machines, representing a refrigerating power equal to that produced by the melting of about 24,000,000 tons of ice yearly. Of these installations, about 300 are afloat, all large liners, war ships, and yachts being fitted therewith as a necessary part of their equipment. On land their use constantly expands in every part of the world, and never before so rapidly as at present. Some of the plants now in course of erection are upon a very extensive scale, as, for instance, one for the Bristol Corporation, and another for the Scottish Cold Storage Co.

and the bearing may be said to have been flattened out into a plate. If the plate is laid upon the wheel and the micrometer adjusted, the hand will be observed to stand at a given mark. If oil is now put into the trough, so that it touches the wheel, it will be observed that the hand of the micrometer has moved, showing that the plate has risen. This means that between the surface of the wheel and the bearing there is a layer of oil on which the bearing is floating. If now we load the bearing we must either squeeze out this layer of oil or the oil must be subject to a pressure sufficient to support the extra load. By means of a hole through the bearing and a pressure gauge, this point can very readily be proved. As will be seen, as the hole is brought to the point of contact between the bearing and the shaft the pressure on the gauge rises to a point that corresponds to the load put upon the bearing. As explained in a paper by the author, printed in the proceedings of the Institute of Civil Engineers, the oil adheres to the surface of the wheel or shaft, and the force of this adhesion is multiplied by the incline formed by the bearing to the shaft. If the hole is put beyond the centre of the shaft the air in the hole adheres to the shaft and is carried round, leaving a vacuum, as shown by the gauge. Under favourable circumstances this vacuum has amounted to 30 in., being within a quarter of an inch of the barometer at the time. The conclusion to be drawn from this experiment is that bearing surfaces that are properly lubricated are separated by a film of oil at a pressure per square inch equal to the load that is upon

them.

The realization of this fact suggests the following rule, which can be easily committed to memory, and is applicable to all classes of bearing. Introduce the oil at the points of least pressure and do not provide a means of escape for it at the points of greatest pressure. It is very easy to find out these points of an ordinary bearing that are least subject to pressure, and the oil can generally be brought there with a little scheming. The means of escape most generally met with are oil holes and channels that frequently occur just at the crown of the bearing where the pressure is greatest.

When the pressure on such a bearing is intermittent, the oil goes in when the pressure is taken off and escapes out again when the pressure comes on, the effect being that the bearing is only able to support a proportion of the load that it could support if lubricated according to the rule. It is quite impossible to lubricate such a bearing at all if subjected to a continuous load. Not a drop of oil will run down the hole at the crown of the

• Paper read before the Institution of Marine Engineers.

bearing, and if the oil is put on the shaft elsewhere it runs out at the hole at the crown.

The diagrams, which we give, represent the principal bearings of the marine engine to which this rule has been applied. No. 1 is the big end of the connecting rod of a vertical inverted marine engine. In this case the two sides are the points of least pressure, and, as will be seen, the oil is led to chambers at the sides. From these chambers suitable inclined planes are provided, and the oil will arrive at the surfaces which have to bear the load at a pressure per square inch equal to the load. It will be noticed that in each case the means of lubrication are in duplicate. This, in the case of large bearings, is strongly recommended, as otherwise one-half of the bearing is only lubricated by the oil that has passed through the other half, and in very large bearings this is not always found to be sufficient, especially when the bearings are new. The double supply of oil is also a great safeguard against failure.

Diagram No. 2 represents the crank shaft bearings. The duty of these bearings is almost identical with that of the big end of the connecting rod. As will be seen, the lubrication is also the same. It seems to be very generally the custom to make these bearings hexagonal or square on the outside. Such a bearing is very difficult to get out to examine or scrape up. The bearing shown is circular, and is prevented from turning with the shaft by a square part on the top half. Such a bearing can be taken out very readily.

Diagram No. 3 represents the little end of the connecting rod. Here again the oil requires to be delivered to the sides the same as to the big end. The diagram shows the oil conducted through the pin. At the end there is a swivel joint. One of the pipes shown brings the oil for the little end and delivers it through the pin; the other pipe brings the oil for the big end and delivers it on the other side into a chamber from which it is conducted by two pipes to both sides of the big end.

Diagram No. 4 shows the general arrangement of these pipes from the lubricators to the bearings.

Diagram No. 5 shows the thrust block. It is strongly recommended that the cooling water should be kept away from the oil, as the mixture of water and oil is an inferior lubricant to pure oil. As will be seen, chambers are formed in the casting through which water can be circulated. There is a difficulty about this form of bearing, in that there is no point of least pressure at which to introduce the oil, so it is necessary to make one. To accomplish this the edges are sloped off as shown on diagram No. 6. With inclined planes such as are shown, it is possible to draw the oil in between the surfaces up to any pressure.

No 2

If once we accept the principle set out in this paper it follows of necessity that a hot bearing is due to a failure of lubrication. If the oil is supplied, as shown by the diagrams, this may be due to the fact that the shaft is not round, is not running true, or else, that it is not smooth enough. Shafts should be finished by clamps lined with emery cloth till they are well polished. Another cause may be that the bearings are not properly fitted. It is no light task to surface up a bearing so that the shaft beds thoroughly.

Having dealt with the subject of the means of lubrication, the next point is the oil. In these days of competition and lowest

tender, very inferior oils are sometimes used in very superior ships. Adulteration of oils is so general that the names by which they used to be known has no longer any real meaning. Whenever it is possible it is the safest way to have the samples of oil examined and reported upon by a chemist, who also has the means of testing the lubricating properties.

Another very important point is the material of which the bearing is composed. Marine engineers seem to be very generally agreed that the bearing should be lined with one of the alloys known as the white metals. These may be divided into three classes. The first contains anything up to 80 per cent. of tin, the second anything up to 80 per cent. of zinc, and the third anything up to 80 per cent. of lead. If we could make sure of always using perfectly neutral oil there would be very little to choose between these three classes, but in order to obtain a neutral oil, such as is prepared for clockmakere, the oil is agitated with zinc and lead shavings, a portion of each is converted into zinc or lead soap, which is afterwards separated from the oil. The principal impurity of lubricating oils is oleic acid, which rapidly corrodes lead and zinc. The plates shown are examples of this. The effect then of using an alloy that contains a large proportion of lead or zinc is that the impurities of the oil combine with the surface of the bearing. Of course this may be avoided by using a very pure oil, but those that are responsible for the lining of the bearing are not always responsible for the quality of oil used, and even if they are at the time they cannot make sure that they will always have it under their control. Tin is not affected by oleic acid or any of the impurities of oil, so the safest way is to use an alloy composed principally of tin, and only containing enough of the most suitable metals to harden it to the utmost. Many of the alloys at present used are too soft and yield with a load of even as little as & quarter of a ton to the inch. Such a metal is liable to squeeze 'out in use. An all-round iining metal ought to stand at least five tons to the square inch without any yield, the best alloys will stand eight tons.

It is a very general custom among marine engineers to hammer the alloy after the bearing is lined. If the alloy is as hard as is desirable it cannot be very ductile, and this hammering cracks it in all directions; if, on the other hand, the alloy is ductile enough to stand hammering, it is conclusive proof that it has too low a compression test to be suitable for lining marine bearings. The author feels considerable diffidence in appearing to lay down the law to those who have had so much more experience of marine bearings. It is, however, right to say that the points dealt with are no untried ideas, but are the result of many years of study on the subject, and a very long series of experiments. It would take too long to even outline these experiments, but they entirely confirm the facts laid before you in this paper.

In the course of a discussion which followed the reading of the paper,

Mr. Fortescue Flannery, M.P., said he was very sorry that owing to his inability to be present at the opening of the meeting he had not heard the whole of the paper, but so far as he had been able to follow it he understood that this machine, shown by the author, had for its object the demonstration of the wedging action of the oil when carried around by the surface of the shaftin other words, that there must necessarily be friction between the oil that was placed in the bearing and the skin of the shafting, so that as the shaft revolved it tended to carry round the oil with it, and that formed, as it were, a film of oil wedged

between the surface of the shaft and the bearing that was about it. Mr. Dewrance had demonstrated to them what might be shown by a model scientifically conceived and ingeniously constructed. It showed clearly to them, in common parlance, that the point of greatest pressure in a bearing was that point in line with the axis of the cylinder, because as the crank came upwards the bottom of the crank pin and the top of the bearing were necessarily subject to the greatest pressure, and similarly on the down stroke the top of the crank pin and the bottom of the bearing

N° 4

CYLINDER

were subject to the greatest pressure. Mr. Dewrance had shown very clearly that if he was right they had hitherto been all wrong. He (Mr. Flannery) was not prepared to say at the moment that there was not something that might be urged against the lecturer's view. He confessed it was a view that was entirely novel to him, and it was extremely interesting, but on the spur of the moment one was not willing to commit oneself to a new demonstration, however accurate and interesting it may appear to be. But Mr. Dewrance had made out a very strong case, and as far as he (Mr. Flannery) could judge at the moment it was a case that was quite unimpeachable. He had shown them that they should introduce the oil at the point of least pressure in a bearing. Hitherto they had always been in the habit of introducing the oil at the top of the bearing, and that was clearly demonstrated by this model, and by the arguments of the lecturer, to be the point of greatest pressure on the up stroke, as the bottom was the point of greatest pressure on the down stroke. He could not help thinking that the system which had been explained to them that evening was one that should be given a fair trial. Mr. Dewrance had not referred to any instance of a practical trial of his system in competition with the ordinary bearings, but personally he (Mr. Flannery) should be only too glad to give this system a fair trial in the hands of one of his people who would do justice to it. He thought the matter of sufficient importance to deserve being dealt with at the earliest possible date. Mr. Dewrance had referred to the difference between square bottom, or hexagonal, and round bottom bearings. In modern practice the system of making the bottom brasses round at the bottom, so that it might be lifted out without lifting the shaft, had become very general, and although that system had some disadvantages, he thought that on the whole the balance of advantages was in favour of the round bottom bearings. There was, for instance, the disadvantage of not being able to line up quite so quickly as in the case of square bottom bearings, but so far as his personal experience went he thought that round bottom bearings offered the greatest advantages, and, generally speaking, he was giving them the preference. With regard to the diagram showing the arrangement proposed by the author for leading the oil pipes from the lubricators to the ends of the connecting rod, it occurred to him that there might be some objection to those long series of pipes