3o6 



NA TURE 



[July 30, 1891 



however, a very different craft from Nelson's old flag-ship. She 

 and her sister-vessel the Grafton are each of 7350 tons dis- 

 placement, and have engines which will develop 12,000 indicated 

 horse-power. Saturday was devoted wholly to a single excur- 

 sion, the members travelling down toChatham by train, and going 

 over the Dockyard. Mr. Yarrow had kindly arranged to send 

 one of his first-class torpedo boats down to Chatham, so that 

 those who wished to return to London by water were enabled to 

 do so. The three great engineering firms, Penns, Maudslays, 

 and Humphrys, also threw open their works to the inspection 

 of members during the meeting. 



We will now proceed to deal briefly with the proceedings at 

 the two morning sittings of Thursday and Friday, during which 

 six papers were read and discussed, of which the following is a 

 list :— Ships of war, by Sir Nathaniel Barnaby, K.C.B. ; on 

 the alterations in the types and proportions of mercantile 

 vessels, together with recent improvements in their construction 

 and depth of loading, as affecting their safety at sea, by B. 

 Martell, Chief Surveyor of Lloyd's Register of Shipping; 

 centre and wing ballast tank suctions in double-bottom vessels, 

 by G. R. Brace ; some notes on the history, progress, and 

 recent practice in marine engineering, by A. J. Durston, 

 Engineer-in-Chief to the Royal Navy ; progress in engineering 

 in the mercantile marine, by A. E. Seaton ; on the weak points 

 of steamers carrying oil in bulk, and the type which experience 

 has shown most suitable for this purpose, by George Eldridge. 



On the meeting being opened. Lord Ravensworth, the Presi- 

 dent of the Institution, who occupied the chair, proceeded to 

 deliver a short address, and then presented the gold medal of the 

 Institution to Prof Lewes for his paper on "Boiler Deposits," 

 read at the last meeting. The gold medal is not given to 

 members of Council, so that some of the papers read at the 

 spring meeting were out of the competition. Sir Nathaniel 

 Barnaby's paper brought forward some of the most salient fea- 

 tures in the history of war-ship design during the thirty-one 

 years which have elapsed since the Institution was founded. An 

 interesting fact noticed was that our earliest armour-clad, the 

 Warrior, and our latest, the Kamillies, wereof exactly the same 

 length — 380 feet. There, however, the likeness ends, for the 

 modern ship is 14,150 tons displacement as compared with 

 9210 tons of the Warrior. Her horse-power is 13,000 in- 

 dicated, the Warrior's being 5270 ; her speed is seventeen and 

 a half knots against the Warrior s fourteen and a half knots ; 

 her armour is 18 inches thick, whilst the ^f^rriw'j was 4^ inches 

 thick ; her coal endurance is 5000 knots as against the Warrior's 

 1210 knots; her weight of broadside is 5500 pounds, as against 

 the Warrior s 1918 pounds. These figures well illustrate the 

 progress made in the science of war-ship construction, and the 

 advance also extends to less desirable elements ; for the cost of 

 the hull and engines alone of the eight first-class battle-ships of 

 the Ramillies class, now in course of completion, is ^875,000 

 apiece, whilst the Warrior cost ;^357,ooo. It may be of interest 

 to our readers if we add that the cost of a first-class battle-ship 

 at the beginning of the century was about /^"jOjOOO. The addi- 

 tion of machinery and other improvements brought the cost of 

 the I2i-gun screw three-deckers, which followed the Crimean 

 War, up to close upon a quarter of a million. The armour alone 

 of the Ramillies has cost exactly the same amount as the Natural 

 History Museum at South Kensington. Bearing these facts in 

 mind, it will be interesting to remember that Lord Brassey 

 has laid down, in the programme of shipbuilding he 

 would propose for the next five years, the number of first 

 class battle-ships as ten ; in addition to six armoured coast 

 defence vessels, six armoured rams, forty cruisers of the first 

 class, thirty look-out ships, and fifty torpedo gun-vessels. 

 Nothing is said about the smaller torpedo boats, although a 

 first-class torpedo beat costs nearly as much as a forty-gun 

 frigate of Nelson's day. Some of our best naval authorities 

 are, however, not so moderate as Lord Brassey ; and Admiral 

 Sir John Hay said, during the discussion on Sir Nathaniel 

 Barnaby's paper, that he would have fourteen line-of-battle 

 ships in place of Lord Brassey's ten. Vast as are the sums 

 involved in the carrying out of such a programme as this, they 

 are not so great, compared to the corresponding expenditure of 

 foreign Powers in terms of the value of the commerce which the 

 ships produced would have to protect. Admiral Sir Edward Free- 

 mantle, Lord Brassey, Sir John Hay, Mr. Wigham Richardson, 

 the Director of Naval Construction (Mr. W. H. White), Sir 

 Edward Reed, and others, spoke in the discussion, which was of 

 a long and interesting description. 



NO. II 35, VOL. 44] 



Mr. Martell's paper described the progress of that part of 

 naval architectural design which bears more particularly on the 

 construction of cargo steamers. The author traced the process 

 of evolution by which the early steamers, naturally modelled 

 after the sailing ships which they succeeded, gave place to later 

 types, which in their turn were displaced by others found to be 

 more suitable to the needs of the time. Mr. Martell dealt largely 

 with the well-decked type upon which so many of the modern 

 " ocean tramps" are modelled. The working of the Load-line 

 Act was also considered by the author. One of the most interest- 

 ing parts of the paper is the few paragraphs the author devotes 

 to sailing ship.s. A few years ago it was freely prophesied that 

 the days of masts and sails were past ; that, so soon as the 

 then existing vessels were worn out, wind-propelled craft would 

 be confined to the yachtsman's sport. From the number of 

 handsome sailing ships that were lying idle in nearly every port, 

 the prognostication seemed warranted. Even the fishing boats 

 seemed "doomed by the multiplication of steam trawlers. 

 Happily for the picturesque aspect of the mariner's craft, these 

 forecasts have not been fulfilled. " Notwithstanding the great 

 economy introduced by the triple-expansion engine," Mr. 

 Martell tells us, "the tonnage of sailing vessels built has yet 

 been well maintained in both 1889 and 1890." Vessels carrying 

 6000 tons of dead weight, with four masts, both ship and barque 

 rigged, have recently been built ; and arrangements have re- 

 cently been made for the construction of a sailing ship, with 

 five masts, to carry 7000 tons dead weight. This vessel is, how- 

 ever, to have a propelling engine fitted aft, but this engine is to be 

 strictly auxiliary, to be used only in case of calms, and to enable 

 the ship to dispense with the use of tugs. If such an arrangement 

 can be conveniently made, and we see no insuperable difficulties, 

 probably there will be a great future for vessels of this class 

 pending the development of coal supplies in various parts of the 

 world. Probably the boiler will take the form of some water 

 tube type yet to be perfected, as quickness in raising steam is a 

 great desideratum for such purposes. An elaborate table of 

 vessels lost during the last ten years is added as an appendix to 

 the paper. A short discussion followed the reading. 



Mr. Brace's paper dealt exclusively with the detail of ship con- 

 struction set forth in the title. As it took exception to Lloyd's 

 rales, Mr. Martell naturally criticized it with considerable 

 severity. 



The sitting of Friday, the 24th inst., commenced with 

 Mr. Durston's paper, which afforded a most interesting con- 

 tribution to the history of the marine engine. The author 

 takes the engine models in the Naval Exhibition for his text, 

 and on them founds a monograph on the evolution of the 

 marine engine as applied to war-ships from the days of the 

 Monkey, the first steam-propelled vessel in the Navy. The 

 Monkey was built at Roiherhithe in 1820, and was 210 tons. She 

 was engined in the same year by Boulton and Watt with paddle- 

 wheel engines of 80 nominal horse-power. It would take too 

 much space to follow Mr. Durston in his description of the sub- 

 sequent development of the branch of the naval service of which 

 he is now the chief ; and with which the names of Penn, Maudslay, 

 Rennie, Seaward, Napier, Elder, and others are so intimately 

 woven in the early, and most of them, happily, in later days. 

 There is added to the paper a table giving particulars of 52 ships 

 of the Royal Navy, commencing with the Acheron — having 

 beam, paddle-wheel engines, and flue boilers, pressed to 4*5 

 pounds per square inch, the machinery being by Seaward — and 

 coming down to the present day. The table is of the greatest 

 value, and we cannot refrain from giving some details from it, 

 even at the risk of extending this notice to undue length. The 

 Acheron, of 293 actual horse-power, gave 2*2 units of power ^ 

 per ton weight of machinery, the piston speed being 198 feet per 

 minute. It required 1074 cubic feet of boiler to give one indicated 

 horse-power. The heating surface per indicated horse-power was 

 5 "25 square feet, and the horse-power per square foot of grate was 

 3"i. The coal consumption is unknown. We will make a 

 jump of 31 years, because that brings us to the first ship in the 

 table of which the coal consumption is recorded. The ship we 

 select is the Hercules, built in 1869, and engined by Penn with 

 trunk engines of 8529 indicated horse-power, and,ofcourse, a screw 

 propeller. The boilers here were of the old rectangular or box 

 tubular type, pressed to 30 pounds per square inch. The piston 

 speed had then steadily risen in somewhat the same ratio as the 

 boiler pressure, so that with the Hercules it had reached to 

 the respectable figure 643 feet per minute. The indicated 

 ' Unit of power = i indicated horse power. 



