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1¢ BULKHEADS NO. 68~ LOOKING FORWARD. ~ HORIZONTAL STIFF XS = "VERTICAL, - ee 12.5" & 4 ! 4 : THE Marine REVIEW 116° OXBUEX 15" CHNNELS. 15° VERTICAL STIFENRS- LUGGED TO TANK. SSS == F Cs 'coeretreellds on | BY" XB" <== WATER FIG. channel to the floor part is over- lapped 18 in. long and connected to- gether with twelve 34-in. diameter rivets machine riveted of the pan head and snap point type. The first thing to be considered in making this lap butt connection is to consider the frame in one piece from the keel to the spar deck. It would be very cumbersome to bend a frame 57 ft. long of this sec- _tion and would not serve the purpose intended in marking same from molds. The principal object in using molds for building ships onthe lakes is to dispense with the one man monopoly and getting as many men as possible both skilled and unskilled on the work at one time. To facilitate the work on the frame channel it is cut in line with the fourth girder, this line being the end of the straight part in the bot- _tom of the ship or a point immediate- ly before the turn of the bilge which runs the whole length of the dead flat of vessel. This connection is simply consid- ered a joint or butt more often used BAX B772X Bh i j eed j i f it tL "64H 6 -10f- TIGHT Door. 9 Soo J iC SLUICE VALVEM t "0 t y \ a =~ 3. The in shipyard phraseology. un- avoidable weakest section governs all calculations of butt connections in a vessel, ; The unavoidable weakest section is the line of rivet holes on a frame 'WATER TIGHT BULKHEADS IN TANK-:° "BALLAST PIPES SEE TANK TOP PLAN. ||} extending from the keel to the Spar deck as shown by midship section | fig. I, : In order to know just what. to do in arranging rivets for, a butt con. nection the strength of the materials is necessary. In _ these calculations steel will be considered for all ma- terials. Tensile strength 28 tons per square inch for unpunched and 26 tons for punched at about 8 diameter pitch and 24 tons for punched at about 4 di- ameter pitch. The 'punching of plates weakens the plate so that accounts for the difference of 2 tons per square inch between punched and plates. The closer the pitch of rivets the greater the material is weakened. The shearing strength of rivets the same as punched material of 8 di- ameter pitch 26 tons per, square inch. To find the strength of material the unpunched j width of plate multiplied by the thick- i ness by strength per square inch gives result for unpunched 'material. Example: A plate 51" X ¥% thick = ol x A" XK 28 = 714 fe { punched plate 51" X 14" = 255 squagte inches. 25.5 -- 3.65 9 X 13-16 hae punched out in plate = 21.85 scfuare inches for punched plate. 21.85 i 26 = 568 tons for punched plate. Shearing strength of 34" digameter rivet = 344 X 3% X .7854 X 26 == 11.486 tons per rivet. ; There will be no rebates, Fin hither- to, on first or 'second clg ss return tickets by trans-Atlantic Fic and uniform saloon rates wil prevail throughout the year. } aR DBLE . | WE | ayy 3? sy! ] --~ Sacha! em -- fap: BeBe, = * ee ee 7 mm prniaggl Ot