=;2o 



NA TV RE 



[March 30, 1893 



problems connected with the propulsion of ships, by Captain 

 E. E. Goulaeff, Imperial Russian Navy. Some experiments on 

 the transmission of heat through tube-plates, by A. J. 

 Durston, Engineer-in-Chief of the Navy. Some notes on the 

 testing of boilers, by J. T. Milton, Chief Engineer Surveyor, 

 Lloyd's Registry of Shipping. On an apparatus for measuring 

 and registering the vibrations of steamers, by Herr E. Otto 

 Schlick. On the repairs of injuries to the hulls of vessels by 

 collisions, stranding, and explosions, by Captain J. Kiddle, 

 R.N. On approximate curves of stability, by W. Hok. Some 

 experiments with the engines of the s.s. Iveagh, by John Inglis. 

 On the cyclogram, or clock-face diagram, of the sequence of 

 pressures in multi-cylinder engines, by F. Edwards. 



Admiral Long's paper was the first taken, and was a useful 

 contribution to a subject which is more of a military than an 

 engineering or constructive interest. Lord Brassey's paper, on 

 the other hand, is chiefly of interest to the shipowner from a 

 commercial point of view, although a very wide imperial matter 

 is encompassed within the scope of the paper. Lord Brassey 

 maintains that this country cannot maintain her supremacy in 

 first-class ocean liners of high speed, and carrying small 

 quantities of cargo, in face of the foreign competition sup- 

 ported by state subsidies. Our own po^t-office contribution 

 for carrying mails is insufficient for the purpose of enabling 

 British shipowners to compete with those of foreign states. In 

 the humbler class of ocean cargo steamers we can hold our own, 

 as proved by the figures quoted. The matter is well worthy of 

 the attention of statesmen. Admiral Long's and Lord Brassey's 

 papers were discussed together, and occupied the whole of the 

 Wednesday morning sitting. 



On the Thursday, the second day of the meeting, a paper 

 by Dr. Elgar was the first on the list, and is the outcome 

 of some remarks made by the author in a speech during the 

 discussion of Mr. Martell's paper of last year upon a similar 

 subject. Dr. Elgar refers to the report of the Board of Trade 

 Committee upon the spacing and construction of water-tight 

 bulkheads in ships, saying that this report raises broadly and 

 pointedly the question of how the strength of a large area of 

 perfectly flat thin steel plating, which is supported at the edges 

 and subjected to normal pressure, may be determined by calcu- 

 lation. This, the author says, is the simplest form of the ques- 

 tion tlius raised. In applying it to the case of a ship's bulkhead 

 we require to deal with a continuous area of plating whose 

 thickness is uniform, but with an area made of separate plates 

 of varying thickness, and connected with riveted joints, which 

 has stiffening bars riveted across in parallel lines at equal dis- 

 tances apart. Dr. Elgar pointed out that what is required is 

 further experimental data upon which to base a theory of use to 

 ship-designers in determining these points. In the discussion 

 which followed Dr. W. H. White, the Director of Naval Con- 

 struction, and assistant controller, supported the author's con- 

 tention, as also did Mr. Martell, the chief surveyor of Lloyd's, 

 and Mr. Bryan, of Cambridge. The two former, who, it is 

 needless to state, are influential members of council, advo- 

 cated that a research committee should be formed for the pur- 

 pose of investigating the matter and accumulating experimental 

 data. Sir Edward Harland, who was chairman of the Board of 

 Trade Committee before referred to, opposed this suggestion 

 on the ground that the Board of Trade Committee had 

 made experiments sufficient for the purpose, and until those 

 experiments had been proved to be defective he thought that 

 any further sums spent would be largely wasted. We do not 

 think the meeting was in accordance with Sir Edward's views. 

 As Dr. White pointed out, the experiments made under the 

 supervision of Sir Edward Harland were more of the nature of 

 experiments on individual girders, rather than on plated sur- 

 faces, supported by stiffeners, the stifTeners being treated as 

 the girders. As Mr. Bryan said, what ship-builders really 

 want is a rule based on scientific investigation by which they 

 can be guided in cases where there is not absolute experimental 

 data. We quite agree with Mr. Bryan that this subject wants 

 to be lifted out of the region of empiricism which has always 

 surrounded it. There is, however, not much prospect of the 

 committee of the Institution being formed, not on account of its 

 being unnecessary, but because there are not sufficient funds at 

 the disposal of the Institution. Dr. White was anxious that 

 the members should be asked to express formal approval of the 

 step to be taken in carrying out this investigation, in order to 

 strengthen the hands of the council. We think, however, that 

 no strengthening of this nature is requisite, for, if we mistake 



NO. 122 2, VOL. 47] 



not, such work as this is directly within the scope of the 

 Institution, as set forth by the original design upon which it is 

 based. 



Lord Brassey, who occupied the chair, advised that the 

 council should memorialise the Board of Trade in order that 

 the Government might take the matter up. No doubt if such a 

 step be taken, a committee will be formed, and those members 

 who have taken a prominent position in the discussion of these . 

 matters would no doubt be willing to act — in fact they could not 

 very well refuse. It is to be hoped also that Mr. Bryan, 

 although not a member of the Institution, will be included 

 in the list. It is very desirable that practical consideration 

 should be kept strictly in view in such a matter as this, but in 

 order to be practical, the investigation should be based on a 

 scientific foundation. There are several naval architects who are 

 mathematicians in the best sense of the word. Mr. Bryan is, 

 however, a mathematician first, and that of a very high order, 

 having distinguished himself at Cambridge. His grasp of me- 

 chanical subjects has also proved considerable, as evidenced by 

 the original work done at the Cambridge Philosophical and 

 his contributions to the British Association, His paper on 

 the buckling of the thin plate will be remembered in this con- 

 nection, and since then he has turned his attention to a study of 

 the buckling of plates. His inclusion in the committee would be 

 a guarantee that any experiments made would include the whole 

 subject and not be simply girder tests. 



Mr. Calvert has take up a very interesting subject for inves- 

 tigation. The measurement of a steamer's wake is a problem 

 that has been looked on by many as practically insoluble, but 

 Mr. Calvert has attacked it in a practical and philosophical 

 manner. He has lowed a large vessel, 260 feet in length, 

 measuring the velocity of the wake by means of towing logs. 

 This vessel was towed from Holyhead to Liverpool. Unfortu- 

 nately the experiment was not so successful as might have been 

 hoped. The speed of the vessel varied during the voyage and 

 the logs only showed the average. The action of the rudder 

 also affected the stream-lines. There were other sources of 

 error. The author therefore was reduced to model experiments, 

 the vessel he used was 28^ feet long, and 3 '66 feet draught. 

 Across the stern was fitted a framework upon which several fine 

 vertical wires were stretched, extending from the deck to some 

 distance below the keel, each of these wires, and the apparatus 

 connected with it, being exactly similar to its neighbours. Upon 

 the wires at the level at which the weight measurement was 

 required a horizontal tube, \ inch internal diameter, was carried 

 by a universal joint near its forward open end. The end of 

 this tube was in communication with another tube, closed at its 

 upper and lower ends, and hung by trunnions to one end of a 

 weighted lever. One of the trunnions being hollow formed a 

 connection through the rubber tube to the under side of a gauge 

 glass inside the model, so that through this system of jointed 

 tubes there was free communication between the gauge glass and 

 the water outside. On the after end of the tube four thin radial 

 feathers were fixed, and as the weight of that end of the 

 system of tubes was accurately balanced by a lever, the hori- 

 zontal tube necessarily assumed a position parallel to the direc- 

 tion of any current in which it might be placed, and its open 

 forward end was consequently always presented normally to the 

 current. 



In order that the attitude of the submerged tube might be 

 noted by the observers in the boat, the vertical tube carried a 

 light rod, the top of which indicated the inclination in any 

 direction of the tube ; four or five of such horizontal tubes were 

 fitted at one time, each on its vertical wire, and having its con- 

 nections as described, and another such tube with similar con- 

 nections was carried by an outrigger reaching out into 

 water that was practically undisturbed. Records were taken by 

 means of a photographic camera. If the water into which these 

 horizontal tubes advanced were at rest, or if its velocity through- 

 out were uniform, then the water in the gauge glasses, rising 

 higher and higher as the speed increased, would still stand at the 

 same level in all the glasses. Assuming that the tube carried by 

 the outrigger was always advancing into undisturbed water, then 

 the water in the gauge glass connected with that tube would 

 serve as a datum line from which, at that instant, the relative 

 elevation or depression of the water in any other gauge glass could 

 be measured, indicating to its corresponding horizontal tube 

 that the water through which it was passing was either following 

 or meeting the boat. The wave of the boat was a disturbing 

 element which had to be allowed for. The data being appraised 



