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he, Mariae Resond.—Supplement. POWER REQUIRED TO PROPEL SHIPS. In making a comparison of the perform- ences of the Burgos and the Jewett in No, 13, Vol. 8, T reckoned the power required for different speeds of the same ship as the squares of the speeds, and I have been asked if I bad not made a mistake, and whether I dia not intend to reckon the difference of the power in the ratio of the cubes of the speeds. The two ships were being compared as to their fuel-cost per ton-mile, and the compu- tation was, right, whereas, if the tuel-cost per hour were in question it would be as the cubes of the speeds. It is probable that many have not thought out thoronghly the}matter of resistance to a vessel passing through the water, and we may as well consider the subject. It will come up again, in future, for the next gener- ation to straighten out for itself. When a vessel is forced through water, the particles of water are thrown aside from the path of the’ vessel.~ They are really thrown, and not pushed, as the particles of earth are pushed from the path of a plow going through a field. When the particles of water yield to the inclined surfaces of the advancing{bow, some of, them are tossed up above the original surtace at the sides, and some of them push away other particles, and these, others in {succession,“until the particles at the surface farther out from the sides are also tossed upward. ‘These tossed particles constitute a wave upon each side of the advancing bow. After the upward movement ofzany‘particle isf{accomplished, it presses by its weight upon the particles next below, and these yield in direction of least resistance (laterally), until the succes- sion of impulses-has éxtendéd outward be- yond the layer originally tossed, and then the direction of least resistance is upward again, and another series of .particles are tossed, to a less height than the first series. These movements are repeated almost in- finitely, and this repetition ot tossings cone stitutes running waves, or rether. waves of translation, to be precise. + _ ‘Phe water closes in behind the passing __ vessel in a manner one degree more complex, bat I think our friends will follow me __ through the rationale, fix the mode of opers tion in their minds, and be able to actually see the thing done when next they go out In still water. . - When the inclined side of the run of a vessel is passing a particle of water, the sup- port of that particle upon. one: side: is re- moved, and falls against thé surface, leaving ‘the next particles without support, so that a ‘succession of particles are falling downward. and toward the inclined and. moving surface. This generates inward ‘currents-of water upon each side of the run, and depresses the water surfaces for @ considerable’ dis-. tance out from the run; In fact, the water falls downward and inward, after the run. surfaces, inversely as it Was tossed upward | and outward by the bow, the result being two lateral currents meeting each other at the after end-of therun, and so meeting, they expend their energy upon -each other by tossing the particles upward, and géner- ating a wave similar to the two half-waves at first generated at the bow, but joined to- gether in one, ‘his wave separatesinto two waves ruaning outwardly, because the fall of each particle is outward and down- ward in the direction of least resistance; until the one following wave is divided into two waves rnuning outward. From this consideration of the matter we see that, in moving a vessel through the water we have not only to move the water aside to the extent of clearing and refilling the path, but we have to toss it up so far that it will run twice as far as it would to “merely escape from the path and to return, were the fluid compressible and perfectly elastic. Z Now, as to the force required to push a well-shaped vessel along at different rates of speed, through a given distance: Let us take one mile for the distance, and twelve minutes for the time required to get over it, and assume the effort to be (1) con- tinued during twelve minutes. In this case we will have tossed all the particles. in the path to a given height, and toa given dis- tance laterally. Now let us take another rate of speed; this: One mile for the distance and six min- utes for the time, and Sonar aan effort must be. There is the same atnunt of water to be removed from the path, which is one mile long. Any particle must be tossed out of the path in half the time allowed in the first supposition, which impels it at a double initial velocity, so that it will go four times as far before it comes to rest, hence, in this laet supposition the effort must be four. As the effortis continued through the same distance in each supposition the power re- quired to doa mile in six minutes willbe four times that required to doit intwelve minutes, The mile run in twelve minutes is equal toa speed of five miles per hour, and the wile run in six minutes is equal to a speed of ten miles per hour, and the powers required are as one to four. This ratio corresponds with the equares of the speeds, five and ten; thus: 6X5=256 :10X10=100::1:4. Hence we say that the power required to propel aship at different speeds over a given dis- tance varies as the squares of the speeds. But if we are considering the power re- quired to propel a ship during given times at given speeds, we say, the required power is as the cubes of the speeds, because: At double speed, in the given time of twelve minutes of the first supposition, the ship would go two miles, and we have already seen that one mile at double speed costs four times the power, so that for double distance at double speed the power required will be: 2X4=8 times that. required in the case of one milé in twelve minutes. Now the cube of any number, is one-eighth the cube of double the number, thus: 5xX5x6=125: 10X10%10=1000::1 :8. Heretofore we have considered the resist- ancé to displacement and replacement sim- ply. There is a separate sort of resistance called skin friction, or eddy resistance, which should be taken into account in estimating the comparative performauce of different ships, but which may be safely ignored io estimating upon the same ships at different speeds, Eddy resistance comes chiefly from rough- ness of the immersed surface. Imagine a single minute pin standing out from an otherwise. perfectly .emooth and repellant ‘surface moving through water. That point would strike particles of water and toss ‘|them out of: ite path, setting up a minute whirl -of water following it. The tossing would be in the same ratio for speeds as the tossing for displacement, and therefore the éddy resistance follows the same ratios as the displacement resistance. Now therough- ‘ness of surface is practically a multitude of pins stuading imaginary perfect surface, and, having determined the power required for one, speed, with a certain state of the ship’s bottom, tt is safe to assume that the whole resistance will be in the ratios above determined for other speeds, up to the speed which begins to break up into short lengths the waves generated by the tossings of dis- | placements; when that speed is exceeded the ratios of resistance increase rapidly. ‘Norman: We Wheeler, in Mechanical Engineer. THE N. W.'T. CO.’S NEW BOAT. ‘Though: the full details of the arrange- ments for the North West Transportation Co’s new boat have not been fully. perfected, yet sufficient progress has been made to justify the announcement that she. will be bulls in Canada; that wood Instead of steel has been selected as the material for the construction; and ‘that she will be in all essential points a sister craft to that pride -l ofthe lakes, the United Empire. She will not be contracted for, but will be built by the company themselyes. Mr. John Dyble having been appointed to prepare the plans and ‘superintend her construction. It 1s ‘the desire of the owners to have the ‘vessel. built in “Sarnia and there is a} ‘reasonably strong probability that this will be: done; though the decision depends to some degree upon the comparison between ‘the arrangements which can be made here and élsewhere for oak timber, some four hundred and fifty thousand feet of which wil) be needed in her construction. [f she is put on the stocks here, whip saws will be rigged and the timbers shaped on the ground; and plates for the boilers will also be cut and fitted on the ground, and the boilers put together in the vessel. Her engines will be of the most modern style, triple expansion compound, sad as large engines of this class have not yet been undertaken in Canada. The machinery will be contracted for either ‘ings. in Great Britain or the United States. As | . The above are some of the preparations for this pattern of engine involves high steam | work which were put into working order pressure, the boilers will be correspondingly | any too soon for the engagements the com- strong, the workin;; pressure which she is} pany already have on hand. They haveun- expected to carry being 150 pounds. The in-} der contract the building of five large triple tention isto begin work on the boat at once to have her ready to launch before the close ot navigation, to have her upper works pu, on and her outfit completed during the winter, and to put her in commission with the opening of navigation of 1889.—Sarnia Canadian. CLEVELAND SHIPBUILDING CO. The Cleveland Shipbuilding Company, has capital stock of one million dollars, and the plant is complete on the grounds lately oc- cupied by the old Cuyahoga Works, the Powell tool company, ete. The buildings occupied by these coneerngs have pot only been torn down, but excavations have been made, extensive retaining walls built, road- ways and railway tracks laid, piles driven to put the river front in good shape, all tomake room for the new enterprise. The following notes are taken of what might be called the four departments in the undertaking; the shipyard itself and its appliances, the boiler shop, the new foundry and the new machine shop. The yard room is obtained by excavating and building retaining wall against Detroit street hill. The latter is eight feet wide at the bottom, four feet wide at top, twenty feet high, and the whole length is 350 teet. The space thus obtained has a river front of 700 feet and an average depth back from the river of 125 feet. On this ground sufficient room is secured, for two berths for vessels, Between these berths and the wall above re: ferred to, are other appliances of the ship- yard. Plate and angle furnaces are both completed.’ Adjoining these are a 1634 foot plate planer, angle shear, largest size, and an angle punch. Here the company also have three. punches and shears built by them- selves and weighing twelve tons each, and capable of punching or shearing 144 inch steel. -Rolls are also soon to be placed into position measuring 163¢ feet between housings, + nd there is also to be a portable punch and shear. In the building above and covering these appliances is the mold loft, a building 40 by 180 feet, which is provided with a band saw for sawing out the molds for the ship. For the boiler shop the com- pany has a building 90 by 200 feet complete in every detail, and for the work to be done there they have provided another punch and shear of their own make same size as in the shipyard, angle punch and level shear, plate planer, 100 ton hydraulic flanger, 100. ton hydraulic riveter, two ton hydraulic crane for the flanger, a.25 ton hydraulhe crane for the riveter, anda plate furnace of size to heat an 8 by 16 plate all over at once. Con- nected with the boiler shop are seven large vaults under Detroit street for fuel, ete. The new foundry is located on Center street, bear the yard and boiler shop. It has a building 60 by 115 feet, with core rooms and ovens, stock house, boiler and engine rooms attached, the brick stack of the works reaching thirty feet above the viaduct, along which the whole building is located. This structure, which it is light and strong, makes a fine appearance. In putting in the floor of the foundry the company has given special thought to making loam and dry sana cast- ‘T'wo-thirds of floor. has a depth’ of 7 feet of molding sand underlaid with tren. beams and holding down bolts. ‘he ap- pliances for. work are three 20 ton steam cranes, two hand cranes of iron, Atcbinson & Little’s hoist in stock house, ete. The cylinder to the engine is 12 by 16 inches, and the boiler to the same a 76 horse power. The building tor the machine shop adjoin- ing)the foundry is 106 teet on Detroit street, 112 feet on the viaduct, is 60 feet wide and five stories high. The first and second floors: are to be used as finishing shops, the third floor for patterns and storage, fourth floor for drawing and pattern shop, and the fifth floor, fronting on the viaduet, for offices. ‘The building was put up by the Brooks building company, A viaduct arch lying between the foundry and machine shop is occupied as an erecting shop. For this purpose itis supplied with a fifteen ton traveling crane, driven by the machine shop engine. It has a span of 69 feet, lift 80 feet 6 inches, and a travel | neoted| of 75 feet. This erecting shop is con with the foundry by railway.” expansion engines, ten large Seotech bollers capable of carrying 150 pounds of steam, and three steel steamers. Two of the latter ‘are for the Lackawanna Transportation Co., of Luffalo, N. Y., and are to be completed dur- ing the spring and summer of 1888, Both steamships will be of the same size, as fol- lows: 280 feét over all, 260 feet keel, 88 feet beam, and 25 feet hold. The other is a ferry steamer, the contract for which, has just been closed, will occupy the berth to be made vacant by the launch of one of the Lacka- wanha steamers, which event will take place on Saturday. ——— CANADIAN CONTESTANTS FOR THE WASP CUP. ? Commodore Gardner, of the Cleveland Yachting Club, has received the following letter relative to the proposed yachting race for a $500 cup to be put up as the prize for the fleetest vessel in a thirty-six mile course. It is likely that all arrangements can be com- pleted, and that several Cinadian yachte will take part. The regatta will likely take place during the last week In June. The following is the letter: a s HaMILtTon, Ont, March, 22, 1888., Secretary Cleveland Yacht Club, Cleveland, O: Dear Sir: ‘The papers have been report- ing a movement on foot in your city.to hold an international regattaon Lake Erie. Oould you inform me what are the conditions pro- posed and class limits?, No doubt you are aware that the Lake Yacht Racing Assocla- tion has always held its cruise and series of races between July 28, and August 16, as this comprises some seven races: Hamilton (2,) Toronto, Charlotte, O:wege, Kingston, Belleville. I doubt if any Ontario yachts would leave this series for Cleveland ‘f your dates were arranged for this period, so I trust you will try and arrange a date not to conflict, as I know of several yachts who would go upto Cleyeland. I would be glad to bring my yacht, the White Wings,’ forty- three feet L, W. L., to compete, for one. What will be your rule of measurement the N. Y¥. Yacht Club rule or Seawanaka, rule? One of these [ suppose, as elther represents the most advanced system. Could .not,the “Verve,”? of Chicago, be got to compete? She is undoubtedly very fast. and having her in would make it very interesting... Last autumn I made an effort to meet the Alice Enright, of Toledo, but she went off toSt. ©lair instead. A sweepstake race between Verve, of Chicago; City of Straits, of De- troit; Alice Enright, of Toledo; Alarm, of Buffalo; Merle, of Oswego; White Wings, of Hamilton; Verve, of Toronto; Oygnet, of ‘Toronto; and your own craft of this size, for, say $100 apiece, would add greatly to the interest of the regatta. As boats under forty- five to fifty feet can’t expect to compete suc- cessfully for the championship against much larger vessels. I would suggest forty-five feet be the limit for a sweepstake race such. as I have depicted. [I believe the scheme lg. quite practicable if some one would only take the initiative, and as Cleveland is about as central a point as any, why not there? I would be glad to.enter, and: Tam sure many, others would also, Aghia Trusting you will exsuse me. for taking: up so much Cf your valuable time, andj tbat: my suggestions will .be.taken’as purely io’ the interest of yachting, and that they.will- meet with your approval, I am yours, ete, - caostig eat guise. So Approa Sanwsgere 36 King street, E. Hamilton, Ont, . +=" —_———_ ae oI . « ‘OFFERS have been made for wheat from Duluth to Buffalo for.4 cents bat the vessels will not accept this, preferring to wait, for- a problematic better rate. « -Furnace -men,are* not buying great quantities of ore as yet~ though considerable has been sold for Lake Michigan furnaces, The sales -have A made at'40 to 50 cen's per tan below last ser son’s rate. ‘here have but-fe cs tracts been made as yet, the largest’ being + Canadian | probably the 120,000 tone of't! Pacific railroad. Receipts at’ obeen*: iS