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gives the plating number. is receiving favorable recognition by owners, builders, insurance companies and classification societies. The construction of wall-sided, bluff-ended freight boats is no doubt partly influenced by considerations of tonnage, partly by facility of construction, as to use a _colloquialism ‘‘they can be built by the mile and cut off as they are wanted”’ and also through the method of taking the classification number, by which the scant- lings of their component parts are regulated. English Lloyds rule for doing this is as follows: Depth, plus half breadth, plus half girth gives theframing number, and the sum of these quantities, multiplied by thelength These two numbers respect- ively determine the sizes of the various plates, bars and ‘beams which go to make up a ship, irrespective of her : displacement or form; so that within the same extreme dimensions two vessels might be built, one of which could have twice the displacement of the other, yet each requiring the same sizes of materials to construct. _ This does not appear to be reasonable because the midship strains to which they would be subject, taking the ships as girders, would be as 3 tol. _ For instance, let A and B represent the two steamers. _If half the displacement of A—1, then half the displace- -ment of B must equal .5, and the strains would be pro- portional to the half displacement multiplied by the dis- tance of centres of buoyancy from amidships thus: A=1 X .5==.5 B=.5 & .33=.166 that is, the strains on A are 3 times as much as those on B Again, suppose we take a block to represent a cargo steamer as A, B, C, D. ~~ -_ Then in order to preserve the same diaplacement and obtain a fine form, let uscut off the four corners E, F,G, -Hand place them amidships butt.end to butt end, we _ have now in the dotted lines.a vessel of the same dis- placement but with enlarged midship section and fine ends. In this case, A==1X .5=.5 B=1 X .33—.33 and the strains are yet greater in A than B, in the pro- ‘portion of .5 to .33, or as 114 to 1, while the classification numbers are much larger in B, owing to the enlarged midship section, and consequently call for heavier scantlings. ‘It is quite evident that the fine ship could be built of considerably lighter scantlings and still have equal strength to the full ship. ' Beam, ‘‘ per se,’’ is no bar to speed, and it must be admitted that the fine ship would be faster with the _ Same power, easier and cheaper to drive, and a better sea boat than the full ship. Her saving in coal would very soon compensate for the slight difference in first cost of shell. Modern battleships and armored cruisers, as built by our own and foreign governments, have tocarry power- -fulmachinery, fuel, armor, armament and equipment as equivalent to the cargo of a freight boat, but their . designers being unrestricted by the conditions referred ;to above, and governed solely by utility, have produced models that are quite different to the orthodox cargo = steamer. If the latter were loaded with propelling ma- chinery to the entire exclusion of cargo altogether, it is » doubtful if she would attain the speed of the'war vessel. These ideas are not new; they have been advocated before by men like Froude, Reed, Denny, Jenkins, Laird and others. (CONCLUDED.) En — MODERN CARGO CARRIERS. Even men familiar with the new records made during 1896, in carrying large cargoes, have little idea of the scope covered by a modern grain cargo. In October of 1896, the Queen City, of Duluth, carried in one cargo from Duluth to Buffalo, 176,000 bushels of wheat. On the average production of 15 bushels per acre it would require 11,200 acres to produce this wheat, or 70 quarter sections, each of which would support for a year in comfort, a family of five, making 350 people at the farm. To transport itto market would require a THE MARINE RECORD. train twomiles long, and when ground int) flour it will feed 35,000 people for one year. To grind it into flour, the ordinary country mill of 150 barrels daily capacity, would have to work night and day for a year, Sundays excepted; and even the big Imperial of Duluth, the largest mill in the world would use up nearly a week in grinding. The value of the cargo in money at Buffalo, the port of destination, was $132,000 and it cost to carry it there $2,640. The entire charges to the farmer at Duluth, wereabout $880, making total charges for the farmer, Duluth to Buffalo of $3,520 or about 3% per cent. of its value. Only a few years back these charges averaged from 12 to 15 per cent. of the grain’s value. —_—— D2 0— a TRAFFIC THROUGH ST. MARY’S FALLS CANAL. REPORT OF FREIGHT AND PASSENGER TRAFFIC TO AND From LAKE SUPERIOR FOR THE MONTH OF OCTOBER, 1896, INCLUDING Sraristics oF THE UNITED STATES AND CANADIAN CANALS aT SAULT STR. MARIE, MICHI- GAN AND ONTARIO: SE ES De Glo ahi sey EAST BOUND. i ISIS SSE SACS, OES Sie SIR SN PS ec le A Ie U.S. Canadian spelen Canal. Canai. Total. --oo——— Copper; met tons. ere 9,447 3,320 12,767 Grain, bushels4. .<s25°37) i 3,320,923 1,441,725 4,762,648 Building stone, net tons.. TOG Seek eh eats 755 Flour, barrels......0......5 831,330 431,290 1,262,620 Tron ore. Net, Conse: is cus erect 490,180 157,319 647,499 ALON PIS. MOL CONG Amos ee 565 2,200 2,765 umber) Mi ft. Bs’ Moss ess sis oe atl Foxe 93,182 1,229 94,411 RUPVEMORC NOU NOUS: nuns; seus ct cstee rct ee he Ine a Wheat, bushels........... 005... 6,824,075 2,730,753 9,554,828 Unclassified freight, net tons 11,641 3,927 15,568 Passengers, number................. 275 257 532 WEST BOUND. ; U: 8. Canadian ITEMS Canal. Canal. | Total. Coal Heras Net¢toOnss pA isc Se 39,197 13,150 52,347 Coal [soft], net tons.................. 193,407 76,290 269,697 RilourL,: barrels} Avis ecko HES BOO EPRRAE Se 150 Grain; DUS GIS iris rn pom a or Ae yee eat Manufactured iron. net tons........ 9,819 2,775 12,594 Salt, barfeles-:s2i sees) hes tes bheis 33 718 80 33,798 Unclassified freight, net tons....... 46,923 5,123 52,046 Passengers, number.......... 0... .. 311 97 408 East bound freight, net’ tons.....6.. 062). 0.6. c cece eccceesecees 1,355,109 West bound freight, nét tons.:..............000-0000050000e, 391418 i; Lotal freight; net-tons; i... wasrtacaotm ta ssnnh Basse: 1,746,527 Total craft, United States, .....:......cscee0s.0000-n 1,425 Total:eraft, Catiadian: :7).0..21.. 26). Se BE ESE 478 RO tuice wr hata Matinee Ee ee er ee 1,903 Total registered tonnage, United States,.................. 1,407,748 Total registered tonnage, Canadian....................... 382,104 Jeu I Detar Sy harem sein & wa mere nic 2 PRP Nee ge a Regan 1,789,852 oor TO CENTRAL AMERICA VIA CHICAGO. The small sea-going steamer Elsa (33 tons) from San- dusky, Ohio, has just made a successful trip up the lakes _ to the Marine Iron Works’ dock, Chicago, where that company will remove her present machinery and put in one of their steeple compound condensing engines; a Worthington surface condenser with combined air and circulating pump, Lunkenheimer fittings, etc., and otherwise fit out the boat for her trip via the Mississippi River to Central America for service on the Gulf of Mexico. Her owners are practical men and understand the value of having machinery and fittings suited to the waters and the work. ll are COPPER SHEATHING OF CRUISERS. Experience is gradually demonstrating, says the Naval and Military Record, the value of copper sheath- ing the underwater structure of cruisers. The latest convert to this process is the United States, whose naval authorities have been collecting information as to the adyantages of sheathing their cruisers with wood and then covering them with copper, to obviate the neces- sity of frequent docking for cleaning the hull. Withan ordinary steel hull it is found that after five or six months afloat about one-fifth more power is required to maintain ordinary cruising speed than when the bottom was clean. In considering the relative advantages of copper and wood sheathing, the fact must not be over- looked that the former process is the more costly. The Naval Defence steel ships of the Latona type cost £171,000, while the wood-sheathed ships cost £ 182,000; but this is soon saved on the coal bill and in docking charges. Indeed, the experience of the British Admir- alty, it is understood, will result in the Secretary of the United States Navy, in his next report, urging that all future cruisers in the navy should be wood-sheathed ‘may further add that Chief Constructor Hichborn, U 7 and copper-bottomed. ‘Two small gunboats now build- ing for the United States government, are to be sheathed in this way, to demonstrate the efficiency. We S..N., has long and strenuously advocated the sheathing of naval vessels; : a MARINE PATENTS. (ILLUSTRATED.) 570,839. Towing Apparatus, Armand DeBovet, Paris, France. Filed April 5, 1894. Serials number 506,451. Patented in France, May 25, 1892, No. 211,852, Claim.—In a towing ‘appara- tus, the combination of an elas- tically-supported -electric ‘mo- f tor, a magnetized friction-pul- Heal’: Jey connected with and adapted to be actuated from said motor, a fly-wheel with which said pulley is in elastic contact, a towing-wheel,.and gearing in- termediate,said towing-wheel and fly-wheel shaft. 570,613. Boat-Propelling Attachment, Samuel N. Smith, Minneapolis, Minn. Filed Nov. 16, 1895. Serial No. 569,151. 3 Claim.—The combination, with an pivotally secured to the boat, of an upright tube adjustably secured to said arm or bracket, i a driving-shaft arranged with- in said tube, a propeller and propeller-shaft supported by said tube, said propeller-shaft being connected by suitable gearing to said driving-shaft, a motor also supported upon said tube and. means connect- ing said motor and said driving-shaft. “ 570,489. Floating Dry-Dock and Ship-Cleaning De- vice, Mark W. Marsden, Philadelphia, Pa. Filed Dec. 6; 1895. Serial No#571,322. nay 570,839 arm or bracket, Claim.—A dry-dock and — vessel cleaner, comprising a hull, water-compartments in said hull, casings along ‘each side of hull forming -a U- shaped space, trans- verse form-sections at one or both ends of said U-shaped space between said casings, substantially as described. 570,680. Steam Steering Apparatus, Chauncey B. Perley, Port Huron, Mich., assignor to the Jenks Ship Building Co., same place. Filed June 12, 1896. Serial No. 595,310. Claim.—In a steam steering apparatus, the combina- tion of a suitably-supported worm-wheel shaft, a wheel held revoluble upon said worm-wheel - ies shaft, said wheel having an eccentric or cam groove, a pilot-wheel, connec- tions whereby the conditions’ of rest or motion of said pilot-wheel may be - |} imposed upon said grooved wheel, a block fashioned totravel said eccentric |\% groove, a bell-crank lever having a’ | fulcrum attached to said shaft and adopted to be revolved therewith, devices pivotally joining said block ’and bell-crank lever, “a revers- ing-valve, pivotal and revoluble connections be- . tween said bell-crank lever and reversing:valve, steam engines arranged to rotate said worm-wheel’ shaft, steam and exhaust ports governed by said reversing valve, said steam ports arranged to serve steam’ to said engines causing them to rotate said ‘worm-wheel shaft in .a direction similar to that imposed upon said grooved wheel by said pilot-wheel. A CONTEMPORARY with more or less truth remarks that the sun is 92,500,000 miles from. the earth, and that the -earth receives only one two-billionth of the solar heat. Furthermore, the nearest fixed star is sixteen-billion miles distant, and takes three years for light, to reach the earth., Well! . Let us trust that. a. few; handfuls of millions of miles don’t count much, even; if, the. figures are a little off. Who’s to.teil, anyway? |