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108 | ae £38' Flanged Washers | or O-6 a THe Marine REVIEW A Dees eo 7 Plate 26-14 Pers lk Holes Td WER 28 A Pen IT MOG , : ae © 0 olg OO ot 1 d) & = oz oi 7 | ; . ' ¥ ; 09°00 : "| b 0000000000 000 fo tavones oo 10 oo00 0000000000 9T 990 mich Dee Ys ' Fic. 2--Front ELEvATION .AND Cross-SEcTION ZTHROUGH COMBUSTION CHAMBER OF Borter ror Tuc Lorne. is a wooden, sea going tug 151 ft. in length, 26, ft, 'beam and,.13.2. ft. .in depth fitted with a single triple ex- pansion engine of 1,100 indicated horsepower. The engine cylinders are 18, 24 and 48 inches in diameter by 36-inch stroke. : As is seen from the accompanying drawing, Fig. 1, the boiler is of the single ended, internal furnace, shell type. It is built to fulfill the require- ments of the British Columbia Marine Inspection. The boiler will carry 170 pounds per sq. in. steam pressure. It ig 11 ft, 7 3/16 in,in length and? 16 ft. diameter. The total water-heating sutface is 2,985 sq. ft.. In comsut'ng the water heating surface one-half the area of each turnace shtell--is tak-n,. together with the tube area and the net area of the combustion chambers. The shell is of open-hearth boi'er steel with a tensile strength of froni 56,000 to 64,000 pounds, with otber physical properties in proportion. The - sl 2 ees @ AE Pras? PA asa { % g _[ealetetetel wreretetate® #6 fee "Se [Teo 6 6 64 6 6 6.6 @ @ GRLN : i ae #,¢ eR) ¥ ol oy Butt Straps/&' Thick, /3PPivers. /&'Drilled Holes Fic. 3--Suowine Pircy or Rivers. ¢ shell is made of two plites eazh 25 ft. long, 11 ft. wide and 13 in. thick. This gives a boiler of a maximum and uniform strength. There are no ring seams and only two longitud:nal seams in the shell. The latter are butt joint, double strap riveted seams with threerows of staggered rivets in each plate. The rivets are 134 in. in diameter, riveted in 1 7/16-in. drilled Holes, As. in' shown: in. Fig. 3, the pitch of the rivets in the two outer rows in each plate is 4% in.; the pitch in the inner tow is 814 in. The butt straps dre 13% in. in thickness. The stayed portion of the head is 13/16 in. thick and the tube sheet is Fic. 4--Britisn Tuc LorNeE For Wuicr main. stays and %4-in. are expanded and beaded into both 13/16 in. thick. The-head is riveted to the shell by a.double staggereq of 13-in. rivets, pitched 454 There are two combustion chambers stayed on the back and sides with 1%4-in. iron screw stays spaced 6 in. center to. center. » The top of the combustion chamber is stayed with. seven crown stays, cach carrying four 13g-in. steel crown bolts. The are. 3. in. in diameter spaced 17% in. horizontally and 19 Tow an: vertically. There are 222 plain tubes, each 3yu in. in outside diameter. and 0.148 in, thick (No. 9, B. W..G), and 114 stay tubes, each 314 in. in diameter thick. °The. stay tubes tube. sheets. There are 336 tubes in -all' with a total water-heating sur- face of 2,488 sq. ft. The stay, tubes are marked "S" on the drawing, Fig. 2, The four internal furnaces are made of %-in. corrugated plate. The fur- naces are 40 in. in internal diameter. The four grates are each 6 ft, 6 in, in length by 41 in. in width, p'aced with a slope of Y%-in. per ft. toward the combustion chamber. There are two furnaces to each combustion chamber. The total grate surface is 88.20 sq. ft, and there are 33.6, 6q, ft;--of. water heating surface per sq. ft..of grate area. The fittings, except the safety valve and the main stop valve, are all mounted on the back head o: the boiler which opens into the engine room of the tug. The safety valve is a 3%4-in. twin valve manufactured by T. McAvity..& Sons. Although the Commercial Boiler - Works will have to pay a duty of 27% per cent ad valorem on this boiler,, the contract was obtained by the American firm in competiton with several boiler makers who would be exempt from this charge. THE Borter 1s BernG BUILT.